EEVblog Electronics Community Forum

Products => Test Equipment => Topic started by: plexus on January 09, 2018, 11:16:53 am

Title: EEVBlog 121GW Discussion thread
Post by: plexus on January 09, 2018, 11:16:53 am
I searched the forum and coulnd't find an appropriate general purpose 121GW thread. So here it is!

Question: what are the various straps in the case to be used for? I can't figure them out.

Here is an unboxing video I made today when mine arrived:

https://www.youtube.com/watch?v=ttpuPpfQqRI&t=14s&ab_channel=plexuss (https://www.youtube.com/watch?v=ttpuPpfQqRI&t=14s&ab_channel=plexuss)

I'll be RTFM now that I have played around with it a bit. It's a very nice meter so far. Feels well built!

Title: Re: EEVBlog 121GW Discussion thread
Post by: Mr.B on January 09, 2018, 12:56:33 pm
I don't have mine yet.
I will be in wave 2 of the shipping (March?).

My question:
The manual specifically says: Battery Type: 4 x 1.5 V AA alkaline battery (ANSI/NEDA 15 A or IEC LR6)

Can anyone (Dave) confirm if it is safe to use the slightly higher voltage Energizer L91 Ultimate Lithium
http://data.energizer.com/pdfs/l91.pdf (http://data.energizer.com/pdfs/l91.pdf)

Many thanks
Title: Re: EEVBlog 121GW Discussion thread
Post by: beanflying on January 09, 2018, 01:46:50 pm
Quick Capacitance check on mine against my HP box. Does that very close 😎
Title: Re: EEVBlog 121GW Discussion thread
Post by: beanflying on January 09, 2018, 02:48:27 pm
Quick resistance check against my 0.02% (1ohm 0.03%) Resistance box. Temp is 25-26 degrees btw.

It does ok below 1 ohm but that territory isn't fair on two wire so just 1 ohm and up was all I have included.

Also tested against some Vishay 0.005% (some pairs) I have 'laying' around  ::)

10k      9.999k
10k      10.000k
500R    0.5000k
500R    0.5000k
100R    100.05
5k        5.000k
Title: Re: EEVBlog 121GW Discussion thread
Post by: knapik on January 09, 2018, 03:43:23 pm
I just got mine earlier today. I'm pretty happy with it so far, but I haven't really gave it any purposeful use yet.

In regards to the question about the straps, I'm pretty sure they're for securing the multimeter and leads like this. I also see that there's another strap on the back, Dave must have liked that multimeter strap patent so much, that he wanted one too ;)
Title: Re: EEVBlog 121GW Discussion thread
Post by: beanflying on January 09, 2018, 03:54:29 pm
Quick DC low Voltage DC tests against an AD584M (closest Reference to hand) as per my Agilent 34401A % deviation to the 34401A of 0.02% or better.

2.49905   2.4989
5.00021   5.0000
7.49955   7.498
10.00028   9.999

AC Voltage and Frequency Referenced to Agilent 34401a.

Mains Testing
Agilent                 121GW
248.07 49.98       249.90 49.95 Hz

Feeltech Sig Gen (don't mention the war) :horse:
5V P-P (indicated) SINE used (1.7677 V rms)
5V P-P (indicated) Square wave used which is fairly clean and sharp under 1MHz
121GW 'Frequency Range' is shown not the dual scale value!
Rough test on Triangle showed reliable Frequency to 1Mhz and consistent Voltage to 100KhZ.

Indicated    Agilent SINE            121GW SINE            121GW Square
50Hz          1.7992    50.002      1.8040   49.997        2.5513   49.997
100Hz        1.7996   100.004     1.8054   99.995         2.5518   99.995
500Hz        1.7998   500.022     1.8049   499.98         2.5461  499.98
1KHz          1.7994    1.0000      1.8109  999.96         2.5521  999.95
10KHz        1.7953   10.0005     1.8408   9.9996        2.6186   9.9995
50KHz        1.7920   50.0022     1.8394   49.998        2.6634   49.998
100Khz      1.7914   100.005      1.8590   99.996        2.6617   99.995
500Khz       1.7745  500.023      .6801    499.98         0.8457   499.98
1MHz          1.8453  1.00005      0.0000  999.95         0.0000   999.96

These tests are really done for me so I have an idea when to break out the Agilent over the 121GW.

First impressions are good, Auto Range is a little slower than I would like but  :-+ :-+ so far.
Title: Re: EEVBlog 121GW Discussion thread
Post by: beanflying on January 09, 2018, 06:13:52 pm
Doing some 'advanced' testing of my reference cabinet. Seems to much 'testing' happening and insufficient drinking the beer is nearly at pommie temp  :-DD

Reference 4 wire RTD against the supplied K thermocouple is within spec at this sort of temp.
Title: Re: EEVBlog 121GW Discussion thread
Post by: fanOfeeDIY on January 09, 2018, 11:07:41 pm
I also made unboxing video. :)

First time to upload a video on youtube.

EEVblog Multimeter Unboxing, Continuity Voltage review
https://youtu.be/tqFaSVsl-R4
Title: Re: EEVBlog 121GW Discussion thread
Post by: lowimpedance on January 10, 2018, 03:13:23 pm
Gotta say the weight of it was a bit of a surprise! but it gives that solid built feel  :-+. Nice addition to my already to large a collection of DMMs  :D.

Pic of my 'Blog' related tools
(yes I have taken its blue jacket of for a closer inspection!)
Title: Re: EEVBlog 121GW Discussion thread
Post by: beanflying on January 11, 2018, 11:30:56 am
Temperature logging commenced. 10s intervals. Nearly time to head to the beach or crack a beer while it logs  8)

edit - topped 30 before midday Beach time (sorry Northerners  >:D )
Title: Re: EEVBlog 121GW Discussion thread
Post by: Terry01 on January 11, 2018, 11:59:31 am
I also made unboxing video. :)

First time to upload a video on youtube.

EEVblog Multimeter Unboxing, Continuity Voltage review
https://youtu.be/tqFaSVsl-R4

Nice 1st video buddy.

The EEV meter looked very slow auto ranging? It was quick showing continuity and never missed a beat. You made a very good point too though that not 1 meter does everything the best. Having a couple (3 or 4) is a good idea as you cover all bases.
Look forward to your next video.
I hope you enjoy your new meter and it's all you hope for. Thanks for sharing  :-+
Title: Re: EEVBlog 121GW Discussion thread
Post by: beanflying on January 11, 2018, 03:33:18 pm
Dropped onto David's Droid software app while the meter was logging Temperature to the card. Hooked up fine and displayed the data in graph form and mirrored the display  :-+

Hit the save button and it allowed me to save the raw captured data from the start of the sync period till then. Would be nice to have maybe a screen capture option as well.

Raw data captured via bluetooth below. Full log to follow off the SD card which is about 1500 records at 10 seconds.

The Time Stamp I haven't tried to figure out? Perhaps David might chime in?

time (s), Temp (°C)
1.734916, 36
3.002225, 36
5.636383, 36
8.999986, 35.9
9.731009, 36
10.41355, 36
10.6082, 35.9
12.41178, 35.8
13.72841, 35.8
14.41105, 36
Title: Re: EEVBlog 121GW Discussion thread
Post by: beanflying on January 11, 2018, 05:09:00 pm
SD card logs follows. Over 1500 records without a glitch (except record 1 being way low?). It is CSV formatted and as the site doesn't allow that format included as Libre Calc and Excel below if anyone is interested.

Couple of observations on the logged data and the format. After the very last record the maximum and the minimum values are stored and will need to be either excluded from the list or moved elsewhere in the data for any post processing. I gather the meter appends them both after each write to the log file? If not can they be moved to the top of the log file with the other headers? If not just something to be aware of.

For a meter that has an internal RTC and Calendar not having an actual time against the recorded data is a PITA.
Basics of it however is it logs data easily and reliably. As you will see from the data there is plenty of other unused columns already.

The sample logs below are a Small log of a VRef last night. Big log of the Temps today (over 36C)  :popcorn:

Title: Re: EEVBlog 121GW Discussion thread
Post by: BravoV on January 11, 2018, 05:12:05 pm
It is CSV formatted and as the site doesn't allow that format ....

Compressed file ZIP is allowed, also usually CSV has high compression rate.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Seppy on January 12, 2018, 12:55:07 pm
Dropped onto David's Droid software app while the meter was logging Temperature to the card. Hooked up fine and displayed the data in graph form and mirrored the display  :-+

Hit the save button and it allowed me to save the raw captured data from the start of the sync period till then. Would be nice to have maybe a screen capture option as well.

Raw data captured via bluetooth below. Full log to follow off the SD card which is about 1500 records at 10 seconds.

The Time Stamp I haven't tried to figure out? Perhaps David might chime in?

time (s), Temp (°C)
1.734916, 36
3.002225, 36
5.636383, 36
8.999986, 35.9
9.731009, 36
10.41355, 36
10.6082, 35.9
12.41178, 35.8
13.72841, 35.8
14.41105, 36

Yeah, so SD card records the samples in a sort of indexed form.
As Bluetooth LE is sensitive to interference and the packet sent doesn't contain the sample index the app records the time that the packet was received successfully.
Title: Re: EEVBlog 121GW Discussion thread
Post by: flano on January 12, 2018, 07:55:24 pm
Is there a link for the firmware download?

I have 1.01, however I see some videos show 1.02?

Thanks Mike
Title: Re: EEVBlog 121GW Discussion thread
Post by: FrankBuss on January 13, 2018, 02:55:10 am
I thought about buying one, because I really like the low burden voltage, logging, and bluetooth connectivity. But this thread (https://www.eevblog.com/forum/testgear/eevblog-121gw-multimeter-issues/) suggests that it might be better to wait for the next revision, especially the reported contact problems of the rotary switch worries me. Can someone confirm this? The other problems, like unusable 7 seconds for ohms autorange, hopefully can be fixed by firmware updates.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Iagash on January 13, 2018, 07:18:53 am
I thought about buying one, because I really like the low burden voltage, logging, and bluetooth connectivity. But this thread (https://www.eevblog.com/forum/testgear/eevblog-121gw-multimeter-issues/) suggests that it might be better to wait for the next revision, especially the reported contact problems of the rotary switch worries me. Can someone confirm this? The other problems, like unusable 7 seconds for ohms autorange, hopefully can be fixed by firmware updates.

Well I had two days fun with the meter and tried a lot of things. I think the switch is fine. Over the time I had a lot "malfunctions" of the switch and think it is firmware related.
One time when I switched the meter on from the right side off-position to the mA range it dropped me into LowZ mode, which is on the other side of the switch next to the left off-Position.
This clearly makes it look like firmware problems.

The build quality of the meter is great and I like the size and I don't care about the slow autoranging, it's still faster than me twiddling the range switch on my manual meter.

The 15V diode test is great and the low burden voltage is also very nice.

But the firmware seems to stem from the shadiest corners of the shenzhen market. No matter in which of the "advanced" software features of the meter I look, it's broken or messed up.

So the future will tell if this becomes a good meter or not. The hardware seems great but until there is a firmware that deserves the name it's hard to tell.

If you want something to play with, get one. If you want a "tool" you can trust I'd rather recommend you wait if UEI will either publish enough of the firmware sources that someone who can writes one or they cobble up a firmware that works. Adding up the issues I found, my guess would be that it rather needs to get rewritten than fixed, since some of the bugs point more in the direction of software design errors (look at the bluetooth protocol thread) than just bugs, but I might be totally wrong on that since I have way too little background information.

At the moment it's not an advanced meter but a well built prototype with basic features and hardware working.

That doesn't mean I regretted it one second to get one. It's just to adjust the expectations on a meter that received very limited testing upto now.

If you want something working, you never buy the first revision.
Title: Re: EEVBlog 121GW Discussion thread
Post by: beanflying on January 13, 2018, 08:32:30 pm
Without knowing the actual code used for the autoranging I would suspect bloated and lazy code may be part of the issue. It is also possible looking at the bar graph that it is running a loop more than necessary to set a range. I think Dave needs a bit of time to get back from his break and do some to and fro with UEI and nothing really can be gained until that happens.

Apart from the bluetooth data issue above I haven't found an issue but I will set up some more logging tests over the next couple of days as my schedule is a bit lighter.

On the rotary switch I like the general feel of it and it works on the stand with two fingers to turn it. Once again no issues with it.

Very unlikely UEI will publish their firmware and I think that has been made more than clear. The original kickstarter without checking only talked about open source on the bluetooth communications protocol? My meter is still on 1.01 btw but perhaps when future updates are made Dave can put up a changelog along with them?

Title: Re: EEVBlog 121GW Discussion thread
Post by: dcac on January 14, 2018, 02:48:15 am
Without knowing the actual code used for the autoranging I would suspect bloated and lazy code may be part of the issue. It is also possible looking at the bar graph that it is running a loop more than necessary to set a range. I think Dave needs a bit of time to get back from his break and do some to and fro with UEI and nothing really can be gained until that happens.

Decent speed on Auto-ranging is such a basic function that you’d think Dave made sure of this during the early stages developing the 121GW. And I can’t really see a reason they needed to change anything, and possibly introduce bugs, in those routines. But I agree that the display behaviour during auto-range seems to do some (weird) extra steps or delays, but still I’m not too optimistic an easy fix is going to speed things up enough.

And also the eevblog “VIP" members who had more insight in the early development doesn’t seem a least bit surprised over this issue - even though it’s been established that the 121GW is twice as slow as the U1282A - a DMM Dave even have >warned< about having “Very slow” auto-ranging.

Title: Re: EEVBlog 121GW Discussion thread
Post by: FrankBuss on January 14, 2018, 02:59:17 am
Decent speed on Auto-ranging is such a basic function that you’d think Dave made sure of this during the early stages developing the 121GW.

Right, that's odd. Usually Dave is not biased and says that some aspect sucks if it sucks, even if he gets money from something. Maybe it is difficult with the high precision? But I guess they could show a few most significant digits fast, then the final result after some seconds if you need it.
Title: Re: EEVBlog 121GW Discussion thread
Post by: 1anX on January 14, 2018, 09:05:59 am
At the moment it's not an advanced meter but a well built prototype with basic features and hardware working.
If you want something working, you never buy the first revision.

From what I've been reading, Iagash has it summed up with his above quote!

The meter I bought from Dave's kickstarter campaign is in the second production run, so I have my fingers crossed the early firmware bugs are sorted. Buying a version 1.0 is always an act of blind faith but I'm sure Dave will get it sorted out once he is back from his break.

I'm tipping it has not been a relaxing time for Dave with a fake campaign running his product and reading of the teething problems with the nicely made and manufactured EEVBlog 121 GW meter. He could not have picked a worse time to be on "holiday" than with the release of a best selling new product. Hurry home Dave we miss you, and your ability to fix complex electronic things, and to make us smile while you do it!

One of the reasons I waited for this meter to become available was that I believed Dave had some great ideas put into its design. Also Dave's character came into play as he comes across a straight talking no BS engineer. The hardware looks good, lets see if the bugs can be fixed quickly as more owners test the meters and more insights become known. 
Title: Re: EEVBlog 121GW Discussion thread
Post by: mattselectronics on January 14, 2018, 12:02:21 pm
I made a short video about it:
https://youtu.be/Ao2Is4LeQIY (https://youtu.be/Ao2Is4LeQIY)

I like it, but the slow auto rangeing is a bit annoying. I hope they can do something about that in software.
Title: Re: EEVBlog 121GW Discussion thread
Post by: 1anX on January 14, 2018, 12:48:12 pm
Matt, I liked the video you made!

You commented on the hassle of getting the SD card out from the meter to have access to the csv file for processing. Maybe Seppy, (Dave 2) can comment, but cant you have access to the csv file from the BLE app? I'm assuming the app on android can use dropbox, etc, or maybe the app is also available for your PC?

I would like to know if this is possible with the app?

The accuracy of the meter looks really good from what I have seen so far, just the slow autoranging holding back its full potential.

Title: Re: EEVBlog 121GW Discussion thread
Post by: beanflying on January 14, 2018, 04:12:36 pm
Dropping the card out is a bit of a PITA. In general use for me I may only log data with this meter occasionally. Even then being able to check Min/Max figures would do me a lot of the time.

On the other hand my two Victor 86B's are strapped to my coffee roaster and get used 10-30 times a week every week. I also have a couple of Agilent DAQ units I am playing with. Plus a heap of independent Temperature logging gear.

Below is some sample data from the shack on why I have a UPS arriving on Monday. On AC the 121GW logs Voltage and Frequency btw. Approximately 40m cable run from the main switchboard over 1kW of commercial refrigeration, 3.3kW of coffee machine or 3.6kW of Roaster plus the electronics gear.  :o

The Voltage troughs in the graph are the elements of the Coffee machine kicking in and out. 10 Seconds per log point.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on January 14, 2018, 05:53:44 pm
Dropping the card out is a bit of a PITA.

It takes me 18 seconds to remove the boot, undo the screws, take off the cover remove the SD card and insert into the PC.
It takes often longer to dick around with a Bluetooth connection.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on January 14, 2018, 05:55:16 pm
You commented on the hassle of getting the SD card out from the meter to have access to the csv file for processing. Maybe Seppy, (Dave 2) can comment, but cant you have access to the csv file from the BLE app? I'm assuming the app on android can use dropbox, etc, or maybe the app is also available for your PC?
I would like to know if this is possible with the app?

It is not possible with the app, the meter firmware does not support this.
This was discussed at the time but UEi said it would not be particularly easy, and with all the other stuff on the list it was decided not to add it Because:
a) The bluetooth app does data logging anyway
b) It fairly trivial to remove the SD card if you are doing long term standlone logging. e.g. <20 seconds to remove the card vs all day logging or whatever, it didn't seem like a big deal.
c) If you are doing a lot of serious data logging then you should have a dedicated and more versatile data logger to begin with.
Title: Re: EEVBlog 121GW Discussion thread
Post by: mattselectronics on January 14, 2018, 10:05:08 pm
Dropping the card out is a bit of a PITA.

It takes me 18 seconds to remove the boot, undo the screws, take off the cover remove the SD card and insert into the PC.
It takes often longer to dick around with a Bluetooth connection.

That is very true, Bluetooth can also be a big PITA.  8)
As soon as there is PC support, I'll probably use that instead anyway.
Title: Re: EEVBlog 121GW Discussion thread
Post by: dcac on January 15, 2018, 08:43:47 am
https://www.youtube.com/watch?v=Zele19jm1MQ (https://www.youtube.com/watch?v=Zele19jm1MQ)

Skip to 16:30 - Dave comments on the auto-ranging speed - infinity to zero ohms, for reference i measured it to 1.6 sec.

Title: Re: EEVBlog 121GW Discussion thread
Post by: dcac on January 15, 2018, 08:50:37 am
https://www.youtube.com/watch?v=9LjWtdgJhkg (https://www.youtube.com/watch?v=9LjWtdgJhkg)

Skip to 12:00 - joe smith comments on the auto-ranging speed - infinity to zero ohms, for reference I measured the Gossen to 4.1 sec and the Brymen to 1.6 sec.

And the 121GW has been measured to 7.4 sec - so in this comparison its really nothing but a toy. Though this was ohms measurements and possibly just an 'annoying' issue - if you instead were measuring potentially dangerous voltages - you really want the meter to show the result as fast as possible so you don‘t have to change focus too long from where/how you’re holding the probes. A good practice is of course to put the meter in its highest manual range if you are expecting high voltages, but if you happen to forget that, or if high voltages happen to be present where they really should not be, then a fast auto-ranging DMM is much safer than a slow one.

The same goes for low voltage measurements - the faster you get the result the less chance it is of slipping with the probes possibly shorting something out causing damage to the circuit.

 
Title: Re: EEVBlog 121GW Discussion thread
Post by: scopeman on January 15, 2018, 12:57:30 pm
Hi Dave,

Nice Job on the 121GW. I was wondering why you did not have the DC volt range go to 1kV. I think that is the only think that holds me back on this meter at the moment.

Maybe in GEN II?

Sam
W3OHM
Title: Re: EEVBlog 121GW Discussion thread
Post by: beanflying on January 15, 2018, 01:40:50 pm
Dropping the card out is a bit of a PITA.

It takes me 18 seconds to remove the boot, undo the screws, take off the cover remove the SD card and insert into the PC.
It takes often longer to dick around with a Bluetooth connection.


That is very true, Bluetooth can also be a big PITA.  8)
As soon as there is PC support, I'll probably use that instead anyway.

True :) If I was likely to use the SD card for remote logging a lot hacking a slot in the side and putting a remote SD reader. Providing the opening was under the boot somewhere would do the job or even a secondary silicone plug for the opening.

About to set up a very boring bluetooth logging session and video it  :=\
Title: Re: EEVBlog 121GW Discussion thread
Post by: amspire on January 15, 2018, 04:47:26 pm
Just noticed that the 1.01 firmware file is on my SD card -

EEVBlog.bin - 117840 bytes - 21st Dec 2017.

i guess the people with firmware 1.02 may have the 1.02 firmware file. Can anyone with 1.02 confirm this? Not sure I actually want to do the update until I get an official update file from Dave. We do not know the difference between the 1.01 and 1.02 firmwares. Could even be a fix for a particular batch of production units that didn't work properly with 1.01.
Title: Re: EEVBlog 121GW Discussion thread
Post by: beanflying on January 15, 2018, 05:08:04 pm
Seems most of the Aussie meters might be 1.01? Not in a rush to try and upgrade at this stage.

Boring as Bat Guano video  :=\ Sorry should have had the 121GW backlight on from the beginning. Switched on about 5 minutes in. Bluetooth hiccuped with the first attempt at connecting but hooked up second time around. The Coffee indecently was delicious  ;D

Log below is what I got from the phone app after the entire session. Seems from looking at the video an expected lag but also plenty of either not sent or dropped points? Also the Frequency doesn't seem to have gone into the log but given the stage of the Apps development and data dropping not a big concern.

https://youtu.be/Pm52dcpq2Ac
Title: Re: EEVBlog 121GW Discussion thread
Post by: amspire on January 15, 2018, 05:14:58 pm
You will definitely get dropped readings on the Bluetooth. The meter is meant to read at 5 times a second I think, but the Bluetooth sends reading only about once per second. It might then take a second or so for the reading to appear on the 121GW App.
Title: Re: EEVBlog 121GW Discussion thread
Post by: FrankBuss on January 15, 2018, 11:22:38 pm
Skip to 16:30 - Dave comments on the auto-ranging speed - infinity to zero ohms, for reference i measured it to 1.6 sec.

Dave was 8 years younger in this video. When you get older, you are not that impatient anymore  ;D
Title: Re: EEVBlog 121GW Discussion thread
Post by: hyvamiesh on January 16, 2018, 03:11:42 am
Anyone know what kind of magnetic strap will fit the meter?
Title: Re: EEVBlog 121GW Discussion thread
Post by: iainwhite on January 16, 2018, 03:40:56 am
The Fluke magnetic hanger that came with my 179 will fit but it has 1/4 inch of play and is not ideal as it is designed for a semi-circular opening (see picture)
However it does hold the 121GW.

Edit:   The Klein tools Model #69190 sold by Home Depot looks like it might fit as it has a square clip.  I will take a closer look next time I visit HD...


Title: Re: EEVBlog 121GW Discussion thread
Post by: dcac on January 16, 2018, 08:20:06 am
Skip to 16:30 - Dave comments on the auto-ranging speed - infinity to zero ohms, for reference i measured it to 1.6 sec.

Dave was 8 years younger in this video. When you get older, you are not that impatient anymore  ;D

Yes but the DMM Dave is reviewing is then also an 8 year old design. And i.e. MCU performance has increased quite noticeably since then - so 121GW should reasonably be expected to be equal or better in auto-range performance.

To me it’s totally unbelievably Dave would use high quality components - like a good reference and a modern MCU - and then severely limit the 121GW’s practical usability with a ridiculously - possibly even dangerously - slow auto-range speed.

Title: Re: EEVBlog 121GW Discussion thread
Post by: IanB on January 16, 2018, 08:42:04 am
To me it’s totally unbelievably Dave would use high quality components - like a good reference and a modern MCU - and then severely limit the 121GW’s practical usability with a ridiculously - possibly even dangerously - slow auto-range speed.

It's not like someone would have said, "let's make it slow", and then did it deliberately. One day you have to ship product. You can't hold back forever, fixing every last detail before letting something out the door. If you do that you won't be in business.
Title: Re: EEVBlog 121GW Discussion thread
Post by: FrankBuss on January 16, 2018, 09:11:48 am
It's not like someone would have said, "let's make it slow", and then did it deliberately. One day you have to ship product. You can't hold back forever, fixing every last detail before letting something out the door. If you do that you won't be in business.

For me 7 seconds autoranging is not a detail, and of course he didn't show this in his Kickstarter video, I guess otherwise it wouldn't have sold that much. But it would be the first thing he would show in one of his EEVblog review videos for other multimeters.

I hope they can fix it in the firmware, then it would be really useful for me. I don't think there are any other meters in this price range and precision, and with all these features, like the VA mode, displaying the burden voltage for current measurement, bluetooth, logging etc.
Title: Re: EEVBlog 121GW Discussion thread
Post by: dcac on January 16, 2018, 09:51:15 am
To me it’s totally unbelievably Dave would use high quality components - like a good reference and a modern MCU - and then severely limit the 121GW’s practical usability with a ridiculously - possibly even dangerously - slow auto-range speed.

It's not like someone would have said, "let's make it slow", and then did it deliberately.

Thanks for pointing that out - I didn't mean to imply it was a deliberate act to make it slow.

This DMM been 2 years under development and I just can't understand how on earth a basic thing like this issue was missed - or supposed to be good enough - you use auto-ranging most of the time you use a DMM - if it has that feature.

Title: Re: EEVBlog 121GW Discussion thread
Post by: IanB on January 16, 2018, 09:59:11 am
This DMM been 2 years under development and I just can't understand how on earth a basic thing like this issue was missed - or supposed to be good enough - you use auto-ranging most of the time you use a DMM - if it has that feature.

Sometimes the reality of working with a distant development team is that you cannot always get what you want out of them. For instance, if they don't know how to make auto-ranging faster, you might ask them again and again to make it faster, and it will be to no avail. If they don't know how to do it, they don't know how to do it. And if you don't own the team, what can you do about that?

I'm not saying this is what happened here, but this is the real world of product development, and things like this do happen. Just read all the complaints from Simon about the sub-contractors he works with...
Title: Re: EEVBlog 121GW Discussion thread
Post by: dcac on January 16, 2018, 10:53:04 am
This DMM been 2 years under development and I just can't understand how on earth a basic thing like this issue was missed - or supposed to be good enough - you use auto-ranging most of the time you use a DMM - if it has that feature.

Sometimes the reality of working with a distant development team is that you cannot always get what you want out of them. For instance, if they don't know how to make auto-ranging faster, you might ask them again and again to make it faster, and it will be to no avail. If they don't know how to do it, they don't know how to do it. And if you don't own the team, what can you do about that?

I'm not saying this is what happened here, but this is the real world of product development, and things like this do happen. Just read all the complaints from Simon about the sub-contractors he works with...

If that was the case - I think it would be very important to provide that information - that the manufacture had failed to meet - what I would call a very basic functionality.

With the secrecy surrounding this project especially in its early stage , perhaps some information might have been missed or messed up i.e. when Dave got somewhat annoyed when he thought joe smith perhaps went too far in his 121GW prototype testing ,several videos was taken down in that event. But what do I know - for sure though I do not think Dave ever was trying to ‘scam’ anyone.

When Dave gets back he can address this the way he feels appropriate. Can the 121GW be speeded up? what auto-range speed would the current HW allow?

Title: Re: EEVBlog 121GW Discussion thread
Post by: beanflying on January 16, 2018, 11:59:11 am


This DMM been 2 years under
....
I'm not saying this is what happened here, but this is the real world of product development, and things like this do happen. Just read all the complaints from Simon about the sub-contractors he works with...

And it is a meter you DON'T have one of and have spent the last 20 of your posts posts beating the drum on one point  :horse:

You have added what to the constructive debate and or knowledge on the product?  ???
Title: Re: EEVBlog 121GW Discussion thread
Post by: dcac on January 16, 2018, 01:50:02 pm
I think re-posting them would add little value at this point.

The only value I can see in those prototype videos would be if they somehow showed (significantly) faster auto-ranging than what's now been determined in the production model.

Title: Re: EEVBlog 121GW Discussion thread
Post by: nidlaX on January 16, 2018, 02:53:36 pm
Not meaning to beat a dead :horse:, but here's another example of slow autoranging on a high end handheld DMM:

https://www.youtube.com/watch?v=goj8HomoKJY&t=3m11s (https://www.youtube.com/watch?v=goj8HomoKJY&t=3m11s)
Title: Re: EEVBlog 121GW Discussion thread
Post by: dcac on January 16, 2018, 07:44:16 pm
@nidlaX - Thanks for your input - and very useful review!

From infinity to zero ohms I measured the Yokogawa to 3.4 sec and the Fluke to 1.9 sec - interesting with the Fluke that the display doesn’t seem to react at first but then it shows the value quickly. Also should be pointed out those DMM only went down to 10milliohms resolution - where the 121GW goes down to milliohms - but I’d give that up anytime for faster speed.

Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on January 16, 2018, 09:45:25 pm
When Dave gets back he can address this the way he feels appropriate. Can the 121GW be speeded up?

Almost certainly.
It is being worked on as the first priority, but do not ask for an update, I do not have one.

Quote
what auto-range speed would the current HW allow?

That's a much harder question to answer. Look at the Keysight 1282A perhaps, that uses the exact same front end chipset.
Title: Re: EEVBlog 121GW Discussion thread
Post by: dcac on January 17, 2018, 07:24:32 am
I think re-posting them would add little value at this point.

The only value I can see in those prototype videos would be if they somehow showed (significantly) faster auto-ranging than what's now been determined in the production model.
So you basically just want to know if anything has changed.  This makes sense.  I setup a very simple test where I placed both the preproduction 121GW and Gossen M248B next to one another with a stop watch.   I then drove the two meters using a common source between there min and max ranges.  So both meters are triggered at the same time for all practical purposes. 

https://youtu.be/Gj9GrW2hi1c

Thanks for showing this!               

And here’s the major WTF moment - infinity to zero ohms - the Gossen is 4.1 sec just like I measured before - but the prototype 121GW is 3.8 sec!! compared to 7.4 sec on the production model I measured in Robert Culver's video - who showed how slow it was compared to his U1253 - a DMM Dave had ridiculed for being slow long time ago.

I wouldn't be surprised if joe got a cleaner more consistent contact is his test and possibly Robert Culver (unknowingly) had a bad probe or lead.
 
Also much of the ‘commotion’ with this issue being people’s different perspective of a fast/slow DMM - and not really prepared for what to expect with the 121GW - which was why I started to measure the time as accurate as possible in the video clips.

The U1282A was 3.5 and about 3.0 sec in 9fps mode - still kinda slooowish but more acceptable and hopefully 121GW can beat that.

Title: Re: EEVBlog 121GW Discussion thread
Post by: kcbrown on January 17, 2018, 07:54:34 am
I think people are ignoring what is perhaps the most important question about this meter:  can it handle a 1.21GW burst of electricity?    ;D

Sadly, nobody has performed such a test, perhaps because it's difficult to put together.  Even Joe might not be able to do that.  Sounds like it might be a good opportunity for him to expand his pulse test equipment lineup.    :-DD

We're rooting for you, Joe!
Title: Re: EEVBlog 121GW Discussion thread
Post by: 1anX on January 17, 2018, 08:35:13 am
When Dave gets back he can address this the way he feels appropriate. Can the 121GW be speeded up?

Almost certainly.
It is being worked on as the first priority, but do not ask for an update, I do not have one.

Quote
what auto-range speed would the current HW allow?

That's a much harder question to answer. Look at the Keysight 1282A perhaps, that uses the exact same front end chipset.

Looks to me like Dave has answered the most asked question in all the numerous discussions on this meter on this forum! Maybe just maybe, we can move on for a moment to some other areas of discussion?

Personally I'm annoyed by this issue just like everyone else, but "for the love of god", (quoted ya Dave) can we give them a little time to bring out the new firmware fix!
Title: Re: EEVBlog 121GW Discussion thread
Post by: joeqsmith on January 17, 2018, 10:03:07 am
I think people are ignoring what is perhaps the most important question about this meter:  can it handle a 1.21GW burst of electricity?    ;D

Sadly, nobody has performed such a test, perhaps because it's difficult to put together.  Even Joe might not be able to do that.  Sounds like it might be a good opportunity for him to expand his pulse test equipment lineup.    :-DD

We're rooting for you, Joe!
Maybe someone will send one to photonicinduction to put across his large cap.   :-DD

Thanks for showing this!               

And here’s the major WTF moment - infinity to zero ohms - the Gossen is 4.1 sec just like I measured before - but the prototype 121GW is 3.8 sec!! compared to 7.4 sec on the production model I measured in Robert Culver's video - who showed how slow it was compared to his U1253 - a DMM Dave had ridiculed for being slow long time ago.

I wouldn't be surprised if joe got a cleaner more consistent contact is his test and possibly Robert Culver (unknowingly) had a bad probe or lead.
 
Also much of the ‘commotion’ with this issue being people’s different perspective of a fast/slow DMM - and not really prepared for what to expect with the 121GW - which was why I started to measure the time as accurate as possible in the video clips.

The U1282A was 3.5 and about 3.0 sec in 9fps mode - still kinda slooowish but more acceptable and hopefully 121GW can beat that.
 

No problem.  Keep in mind both meters change states at the same time.  You can't tell when this happens in the video, only that the meters do eventually start to respond.   You can however tell which meter is faster by which settles first.  There is a fair amount of variance.  Again, I am not mechanically switching the signals for these tests.  As far as the response of the meter, consider the switching errors in the setup negligible.

For those of you that have an obsessive compulsive disorder, I setup another test.  This time using the a frequency counter and Arb to count 1ms events.  Events are sent to the counter at the same time the signals are sent to both the Gossen and prototype UEI meter.    After 10 seconds, I remove reset each meter to their over range state. 

I made four short to open cycles.  Sorry but the high frame rate of the camera limits recording to 4 seconds and the meters are just too slow to capture the entire event.   So I stretched the start and stop of each event to help provide a better estimate.   

For the true OCD people out there, this is not going to be enough.  So I set the camera to manual trigger at 1000fps.  I then captured the last few seconds where the meters settle.  I then repeat this a second time.  Just in these two cycles, we can see the UEI meter change by roughly 40ms and the Gossen by 80ms.   

Again, I can't stress enough that this is NOT the released camera meter.  :-DD  It was an early prototype that Dave provided.  The data shown may not be representative of the released product.

https://youtu.be/13nv-NsQXDs



Title: Re: EEVBlog 121GW Discussion thread
Post by: ez24 on January 17, 2018, 01:08:18 pm
I think people are ignoring what is perhaps the most important question about this meter:  can it handle a 1.21GW burst of electricity?    ;D
Since that is enough to power 1,000,000 homes it might require a shunt. 
Title: Re: EEVBlog 121GW Discussion thread
Post by: VK5RC on January 17, 2018, 09:31:20 pm
I have done a rough-as-guts comparison of my handheld DMM collection in terms of resistance Auto-ranging time.
The winner ( - chicken dinner) is a 3458 (not fair I know) but then a Gossen. The 121GW is quite close to the Keysight U1282A - as Dave states above -the same chip.

https://www.youtube.com/watch?v=9KY8001f8rk (https://www.youtube.com/watch?v=9KY8001f8rk)

Edit, Grammar
PS If I recall, Dave's criticism of the U1253 was mainly the timing of 'continuity' not the standard resistance range. The U1253B is slow in continuity but does give a reading of ohms - presumably for short finding.
Title: Re: EEVBlog 121GW Discussion thread
Post by: ez24 on January 18, 2018, 05:49:52 am
I have done a rough-as-guts comparison of my handheld DMM collection ....

If you turned on everything, you would need a 1.21 GW meter to measure the kW used.   :-DD
Title: Re: EEVBlog 121GW Discussion thread
Post by: Terry01 on January 18, 2018, 06:45:02 am
Holy Smokes!

Is all that equipment for home/hobby use?
Title: Re: EEVBlog 121GW Discussion thread
Post by: VK5RC on January 18, 2018, 12:15:13 pm
Don't tell my wife! HiHi
It is about 20yrs of selective purchases.
No,  she knows, I don't look at her shoes / handbags / lululemon running gear!

I wanted to post the big variations in hand dmm autoranging time.
Title: Re: EEVBlog 121GW Discussion thread
Post by: dcac on January 18, 2018, 02:34:46 pm
@VK5RC - Thanks for testing your 121GW again and provide even more comparisons with your other DMMs - indeed an impressive collection you have there.

I also thought I mention this as it might help tracking down a possible bug. Even though the probes seems to be closed firmly - the bargraph flicker a couple of times just as if there was intermittent connection. I thought I saw the same flicker in the first video and that’s why I made that comment earlier about the probes possibly being bad. But from what I can tell now - the flicker seems to happen in more or less the same place in the auto-ranging sequence - most noticeably when going from Mohms to Kohms.

The bargraph on Joe’s prototype 121GW did not seem to flicker at all.

Title: Re: EEVBlog 121GW Discussion thread
Post by: dcac on January 18, 2018, 03:12:35 pm
The bargraph on Joe’s prototype 121GW did not seem to flicker at all.

No but in that last attempt you can clearly see the fade in vs the half and half, or should I say half + 1 segment.   :-DD   

I could run a side by side of the meters that have survived all my abuse along with the counter to time it.  Seems like an easier way to measure them anyway.  My old analog meter settles pretty fast but does not have auto ranging.  :-DD

Just to clarify - in my previous post I meant the two times Robert Culver tested his 121GW I saw the bargraph flicker in more or less the same place - as if the connection between his probes was intermittent. Compared to your prototype where the bargraph did not seem to flicker at all. Possibly this could be the indication of a bug the auto-ranging routine in Robet’s 121GW that causes bargraph flicker and overall slow auto-ranging speed.

Title: Re: EEVBlog 121GW Discussion thread
Post by: beanflying on January 18, 2018, 03:15:29 pm
Seems either the meter and or the reference has drifted 2 LSD.  Decided not to try and figure out which as Yep that is 42+ degrees C on the bench  :phew:
Title: Re: EEVBlog 121GW Discussion thread
Post by: beanflying on January 18, 2018, 03:19:37 pm

Just to clarify - in my previous post I meant the two times Robert Culver tested his 121GW I saw the bargraph flicker in more or less the same place - as if the connection between his probes was intermittent. Compared to your prototype where the bargraph did not seem to flicker at all. Possibly this could be the indication of a bug the auto-ranging routine in Robet’s 121GW that causes bargraph flicker and overall slow auto-ranging speed.

Just to clarify you are relying on the videos of others for the content of your last 25 posts to search for any perceived (by you) flaws in a product you haven't used in the flesh?  :palm:
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on January 18, 2018, 10:39:59 pm
Seems either the meter and or the reference has drifted 2 LSD.  Decided not to try and figure out which as Yep that is 42+ degrees C on the bench  :phew:

Reminds me of the old garage EEVblog lab. In old videos you can see the sweat running down my forehead.
Title: Re: EEVBlog 121GW Discussion thread
Post by: iainwhite on January 19, 2018, 12:55:52 am
Has anyone in the USA received theirs?

Joe, I received mine on Jan 8th.   I think there were at least a couple of other US guys that have too.
Title: Re: EEVBlog 121GW Discussion thread
Post by: dcac on January 19, 2018, 01:10:44 am
Just to clarify you are relying on the videos of others for the content of your last 25 posts to search for any perceived (by you) flaws in a product you haven't used in the flesh?  :palm:

Interesting comment on a Video blog related forum. For me videos are very useful to evaluate a product’s performance or apparent flaws, sorry if you can’t do that, please feel free to ignore my posts.

Title: Re: EEVBlog 121GW Discussion thread
Post by: idpromnut on January 19, 2018, 05:56:22 am
Probably off topic (a bit), but I am ashamed to say that the significance of this evaded me (as I was busy exploring the meter functionality, and not the serial number on the back):
Title: Re: EEVBlog 121GW Discussion thread
Post by: logictom on January 19, 2018, 08:23:20 am
Just to clarify you are relying on the videos of others for the content of your last 25 posts to search for any perceived (by you) flaws in a product you haven't used in the flesh?  :palm:

Interesting comment on a Video blog related forum. For me videos are very useful to evaluate a product’s performance or apparent flaws, sorry if you can’t do that, please feel free to ignore my posts.

I don't see the issue with this. I think some people are getting a little bit too fanboy, don't get me wrong, I bought one aswell with the explicit need, it's always good to have more meters and to support Dave. How is critiquing this from video any different to us all saying how dumb apple was to remove the 3.5mm jack on the latest iPhone without most of us owning one.

Banging on the same issue in multiple posts without adding anything to the discussion is another thing, but evaluating a product via video and without owning it - how else would we decide on what to buy from all these online only retailers.
Title: Re: EEVBlog 121GW Discussion thread
Post by: maukka on January 20, 2018, 03:06:21 am
Did a 10 hour logging of temperature simultaneously with a Uni-T UT181A at 60 second sampling interval. Also another one for voltage for a couple of hours at 1 second interval while discharging a battery. Was very happy to find that they're perfectly in sync. While a Mooshimeter for example drifts compared to them.
Title: Re: EEVBlog 121GW Discussion thread
Post by: 1anX on January 20, 2018, 02:32:10 pm
I wrote the following on another thread in this forum after Dave made clear that the wobbly switch issue had been confirmed. I think its more appropriate that its posted on the "Discussion" thread!

It doesn't matter to me about what the details were of the past prototypes!

I'm concerned about the current production models and what I'm going to receive come March 2018. Its not so much about the existence of the problems encountered with the production model, but about how it will be fixed.

There are two items of concern and they are the current meters now delivered may have a hardware issue and how will this be addressed?

The Kickstarter way of buying a new meter is certainly a new experience for me, as it is without certainty or guarantee. I would not have engaged in the campaign if not for finding Dave and his blog to be 100% genuine. I'm certain the existing owners will be looked after and the next batch of meters will be fixed before being shipped.

Dave we need you to communicate a reassurance that hardware and firmware will be fixed. We are all reasonable people and understand this may take some time. Give us one of your EEVBlogs on how the Kickstarter project meters have some issues and whats needed to fix them. Give us some of your trademark sarcasm and humour and include us, (the backers) in how you progress from here. 
Title: Re: EEVBlog 121GW Discussion thread
Post by: tpw_rules on January 21, 2018, 06:40:51 am
Is the fully open schematic available yet? I'd like to get a peek to answer some questions.

Relatedly, I've cooked up a firmware with a tweak to autoranging that should improve the speed significantly. Trouble is, I've not yet received my meter. Anybody want to PM me and give it a go?
Title: Re: EEVBlog 121GW Discussion thread
Post by: bicycleguy on January 21, 2018, 01:07:39 pm
Asked that on the kickstarter page and received this from Dave on January 15th:

They are being neatened up by UEI soon to be released, it will be posted in an update.
Title: Re: EEVBlog 121GW Discussion thread
Post by: mikeselectricstuff on January 21, 2018, 08:34:26 pm
Asked that on the kickstarter page and received this from Dave on January 15th:

They are being neatened up by UEI soon to be released, it will be posted in an update.
Any word on publishing the format of the cal data and firmware files - these would be prerequisites for alternative firmware - probably possible to reverse-engineer, though it would be a bit of a pain.
BTW is a full end-user recalibration possible ( this would make reversing the cal data easier if nothing else)?
Title: Re: EEVBlog 121GW Discussion thread
Post by: dcac on January 21, 2018, 11:10:31 pm
BTW is a full end-user recalibration possible ( this would make reversing the cal data easier if nothing else)?

Seems to be, have a look at page 58 in the manual:

http://www.eevblog.com/files/EEVblog-121GW-Manual.pdf (http://www.eevblog.com/files/EEVblog-121GW-Manual.pdf)
Title: Re: EEVBlog 121GW Discussion thread
Post by: mikeselectricstuff on January 21, 2018, 11:18:38 pm
BTW is a full end-user recalibration possible ( this would make reversing the cal data easier if nothing else)?

Seems to be, have a look at page 58 in the manual:

http://www.eevblog.com/files/EEVblog-121GW-Manual.pdf (http://www.eevblog.com/files/EEVblog-121GW-Manual.pdf)
Quote
4. Hold your breath, cross your fingers, and don't make any sudden
movements that could frighten the meter. Beard stroking is allowed.
What, no tongue angle specification ?

Title: Re: EEVBlog 121GW Discussion thread
Post by: tpw_rules on January 22, 2018, 03:08:07 am
Any word on publishing the format of the cal data and firmware files - these would be prerequisites for alternative firmware - probably possible to reverse-engineer, though it would be a bit of a pain.
BTW is a full end-user recalibration possible ( this would make reversing the cal data easier if nothing else)?

So, IDA and I have been having a bit of fun over the past week and I now have a perhaps 80% complete IDA database of the 1.02 firmware. I'm hesitant to release it because a) it's not done and b) I don't know what UEI would think. I also can't test a lot of theories because my own meter is not here yet.

Anyway, regarding the format of the firmware file. The CPU is an STM32L152 family Cortex-M3 ARMv7-M processor. I don't know what exact chip it is. If anyone could send me a photo of the exact chip in the meter, I would be grateful. The EEVBlog.bin file is burned into ROM starting at 0x08006000. It has a standard Cortex-M3 vector table at the start, where the first 32 bits are the initial SP and the second are the reset vector (+ 1 because the processor always operates in Thumb-2 mode). This is enough to get it disassembling correctly in IDA, or to start your own firmware once the exact chip is known.

Regarding calibration data, it actually seems possible to load and save the calibration area of the EEPROM to the SD card. As before, I can't test it cause I don't have a meter. There is a non-zero chance you could lose all your cal data or start a fire.  If you want to try, here is the procedure:
The cal.bin file is a copy of the first 1200 bytes of EEPROM. The first 48 bytes are used for settings, the rest of the 1200 bytes is calibration factors, and the rest of the EEPROM is involved with logging.

A lot of the ranges share factors and there are some I'm not too sure about. The official manual is pretty light on details, and it seems there are other things such as a bonus 50Mohm range calibration and some frequency calibration factors for the AC ranges which are not mentioned. (And what's with 10% for the AC ranges? Is that 10% of full scale as opposed to a dead short?) Fortunately, for most modes and ranges, it is indeed a simple 0 offset and a full-scale gain and I know which ones use which factors. Sadly, I'm not a metrologist, and these areas are heavy on algorithms I don't understand, so I'm having trouble. But I intend on communicating whatever I learn when I do learn it.

And Dave, could you give me an OK/over my dead body on releasing the work?
Title: Re: EEVBlog 121GW Discussion thread
Post by: fanOfeeDIY on January 22, 2018, 03:38:50 am
I just uploaded a video reviewing current measurements of 121GW, Fluke 87-V, Keysight U1241B.

I did not spend much time for rendering, and my camera is not good at auto focusing so
at least I tried to have the voice quality reasonable.

Please enjoy. :)

https://youtu.be/EfV_u2MFOPU
 
Title: Re: EEVBlog 121GW Discussion thread
Post by: mikeselectricstuff on January 22, 2018, 03:44:39 am
Any word on publishing the format of the cal data and firmware files - these would be prerequisites for alternative firmware - probably possible to reverse-engineer, though it would be a bit of a pain.
BTW is a full end-user recalibration possible ( this would make reversing the cal data easier if nothing else)?

So, IDA and I have been having a bit of fun over the past week and I now have a perhaps 80% complete IDA database of the 1.02 firmware. I'm hesitant to release it because a) it's not done and b) I don't know what UEI would think. I also can't test a lot of theories because my own meter is not here yet.

Anyway, regarding the format of the firmware file. The CPU is an STM32L152 family Cortex-M3 ARMv7-M processor. I don't know what exact chip it is. If anyone could send me a photo of the exact chip in the meter, I would be grateful. The EEVBlog.bin file is burned into ROM starting at 0x08006000. It has a standard Cortex-M3 vector table at the start, where the first 32 bits are the initial SP and the second are the reset vector (+ 1 because the processor always operates in Thumb-2 mode). This is enough to get it disassembling correctly in IDA, or to start your own firmware once the exact chip is known.

Regarding calibration data, it actually seems possible to load and save the calibration area of the EEPROM to the SD card. As before, I can't test it cause I don't have a meter. There is a non-zero chance you could lose all your cal data or start a fire.  If you want to try, here is the procedure:
  • Boot holding the MEM key, or maybe boot the meter with no keys and quickly press MEM. (I'm not entirely sure) Screen will show SdCAL if you did it.
  • Press PEAK to load calibration data from SD card (screen shows SdSEt) or REL to save data to card (screen shows SdSAv).
  • Press MODE to do it. If successful, screen shows SAvEd. Else, screen shows -Err-.
  • Turn off the meter. The data is now in cal.bin on the SD card.
The cal.bin file is a copy of the first 1200 bytes of EEPROM. The first 48 bytes are used for settings, the rest of the 1200 bytes is calibration factors, and the rest of the EEPROM is involved with logging.

A lot of the ranges share factors and there are some I'm not too sure about. The official manual is pretty light on details, and it seems there are other things such as a bonus 50Mohm range calibration and some frequency calibration factors for the AC ranges which are not mentioned. (And what's with 10% for the AC ranges? Is that 10% of full scale as opposed to a dead short?) Fortunately, for most modes and ranges, it is indeed a simple 0 offset and a full-scale gain and I know which ones use which factors. Sadly, I'm not a metrologist, and these areas are heavy on algorithms I don't understand, so I'm having trouble. But I intend on communicating whatever I learn when I do learn it.

And Dave, could you give me an OK/over my dead body on releasing the work?
Maybe start a new  hacking thread?
Title: Re: EEVBlog 121GW Discussion thread
Post by: bicycleguy on January 22, 2018, 05:13:36 am
I just uploaded a video...

Surprised you didn't mention the burden voltage on the 121's secondary display.  I see you didn't hook it up in the video, but would have been nice to compare it's value with the other meters.

thanks
Title: Re: EEVBlog 121GW Discussion thread
Post by: Iagash on January 22, 2018, 06:22:10 am
Maybe start a new  hacking thread?

There is already one: https://www.eevblog.com/forum/testgear/eevblog-121gw-multimeter-firmware-details/ (https://www.eevblog.com/forum/testgear/eevblog-121gw-multimeter-firmware-details/)
Title: Re: EEVBlog 121GW Discussion thread
Post by: ez24 on January 22, 2018, 08:06:51 am
Maybe start a new  hacking thread?

There is already one: https://www.eevblog.com/forum/testgear/eevblog-121gw-multimeter-firmware-details/ (https://www.eevblog.com/forum/testgear/eevblog-121gw-multimeter-firmware-details/)

Thanks 

Now that there is talk of firmware hack, I am starting to get interested because I think someone is going to come up with something to make me want to buy one.  I am sure UEI does not understand this.

Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on January 22, 2018, 09:01:03 am
Any word on publishing the format of the cal data and firmware files - these would be prerequisites for alternative firmware - probably possible to reverse-engineer, though it would be a bit of a pain.
BTW is a full end-user recalibration possible ( this would make reversing the cal data easier if nothing else)?

So, IDA and I have been having a bit of fun over the past week and I now have a perhaps 80% complete IDA database of the 1.02 firmware. I'm hesitant to release it because a) it's not done and b) I don't know what UEI would think. I also can't test a lot of theories because my own meter is not here yet.

Anyway, regarding the format of the firmware file. The CPU is an STM32L152 family Cortex-M3 ARMv7-M processor. I don't know what exact chip it is. If anyone could send me a photo of the exact chip in the meter, I would be grateful. The EEVBlog.bin file is burned into ROM starting at 0x08006000. It has a standard Cortex-M3 vector table at the start, where the first 32 bits are the initial SP and the second are the reset vector (+ 1 because the processor always operates in Thumb-2 mode). This is enough to get it disassembling correctly in IDA, or to start your own firmware once the exact chip is known.

Regarding calibration data, it actually seems possible to load and save the calibration area of the EEPROM to the SD card. As before, I can't test it cause I don't have a meter. There is a non-zero chance you could lose all your cal data or start a fire.  If you want to try, here is the procedure:
  • Boot holding the MEM key, or maybe boot the meter with no keys and quickly press MEM. (I'm not entirely sure) Screen will show SdCAL if you did it.
  • Press PEAK to load calibration data from SD card (screen shows SdSEt) or REL to save data to card (screen shows SdSAv).
  • Press MODE to do it. If successful, screen shows SAvEd. Else, screen shows -Err-.
  • Turn off the meter. The data is now in cal.bin on the SD card.
The cal.bin file is a copy of the first 1200 bytes of EEPROM. The first 48 bytes are used for settings, the rest of the 1200 bytes is calibration factors, and the rest of the EEPROM is involved with logging.

A lot of the ranges share factors and there are some I'm not too sure about. The official manual is pretty light on details, and it seems there are other things such as a bonus 50Mohm range calibration and some frequency calibration factors for the AC ranges which are not mentioned. (And what's with 10% for the AC ranges? Is that 10% of full scale as opposed to a dead short?) Fortunately, for most modes and ranges, it is indeed a simple 0 offset and a full-scale gain and I know which ones use which factors. Sadly, I'm not a metrologist, and these areas are heavy on algorithms I don't understand, so I'm having trouble. But I intend on communicating whatever I learn when I do learn it.

And Dave, could you give me an OK/over my dead body on releasing the work?

No problem.
I'm not going to stop hacking, it is encouraged.
And you are right, there is a boot key press mode that saves the CAL data to SD card. v1.01 firmware has a bug in this routine that was fixed in v1.02 (no other changes). Haven't added this to the manual yet.
Title: Re: EEVBlog 121GW Discussion thread
Post by: dcac on January 22, 2018, 09:17:50 am
Maybe start a new  hacking thread?

There is already one: https://www.eevblog.com/forum/testgear/eevblog-121gw-multimeter-firmware-details/ (https://www.eevblog.com/forum/testgear/eevblog-121gw-multimeter-firmware-details/)

Perhaps it's best to keep that one for official firmware details. And start a new thread dedicated to firmware Hacking.

Title: Re: EEVBlog 121GW Discussion thread
Post by: benst on January 22, 2018, 11:21:19 am
Is there anything known about when (if?) we can expect the iOS app? Looking forward to that!

Thanks,
Ben
Title: EEVBlog 121GW Discussion thread
Post by: fanOfeeDIY on January 22, 2018, 02:40:05 pm

Surprised you didn't mention the burden voltage on the 121's secondary display.  I see you didn't hook it up in the video, but would have been nice to compare it's value with the other meters.

thanks

I thought the same, I spent too much time in the first half of explaining USB-UART converter part and wanted to save time with just swapping the meter.
I would like to included it in the future review.
Title: Re: EEVBlog 121GW Discussion thread
Post by: MatthewEveritt on January 23, 2018, 03:07:16 am
Anyway, regarding the format of the firmware file. The CPU is an STM32L152 family Cortex-M3 ARMv7-M processor. I don't know what exact chip it is. If anyone could send me a photo of the exact chip in the meter, I would be grateful.
See here https://www.eevblog.com/forum/testgear/eevblog-121gw-multimeter-issues/msg1406994/#msg1406994] [url]https://www.eevblog.com/forum/testgear/eevblog-121gw-multimeter-issues/msg1406994/#msg1406994 (http://[url)[/url]
Title: Re: EEVBlog 121GW Discussion thread
Post by: jordanp123 on January 23, 2018, 07:23:29 am
Any news on the US meters?
Title: Re: EEVBlog 121GW Discussion thread
Post by: logictom on January 23, 2018, 11:13:31 am
I am having trouble using the Bluetooth, I've got the BT icon on the meter, I have detected the meter on my phone, Google Pixel, and connected, now showing in my paired list, but I see nothing in the app.

Actually just got it to show in the app by forgetting the connection in android settings. But now I've closed the app I cannot get it to reappear.

I've tried the alternative app but that always responds Ble device not found.

Is there a particular sequence on must follow to get it to appear in the app?

When it was connected there appears to be an issue with the fonts in the upper left, auto DC
Title: Re: EEVBlog 121GW Discussion thread
Post by: ez24 on January 23, 2018, 11:21:14 am
I am having ....

Can I ask a stupid question - how did you get that screen shot ?

thanks
Title: Re: EEVBlog 121GW Discussion thread
Post by: Cliff Matthews on January 23, 2018, 11:41:31 am
I am having ....

Can I ask a stupid question - how did you get that screen shot ?

thanks
Roger, this should help. *edit (but you'll have to pull the jpg from the phones DCIM folder and copy or send it to a PC - YMMV)
https://www.greenbot.com/article/2825064/android/how-to-take-a-screenshot-on-your-android-phone.html (https://www.greenbot.com/article/2825064/android/how-to-take-a-screenshot-on-your-android-phone.html)
Title: Re: EEVBlog 121GW Discussion thread
Post by: MagFlux on January 23, 2018, 05:14:32 pm
The iOS App has been available in Canada for a week. You may need to search the App Store daily as it could be released where you are very soon.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Halcyon on January 23, 2018, 05:24:18 pm
Feature request

Could you include an option in the setup to disable the beeper? It's fine for power-on events and continuity testing etc... but it becomes more of an annoyance every time you turn the knob or press a button. I understand the reasoning behind it, but for me, I'd prefer to have the option to turn it off for key presses/mode changes (or at least select a lower volume).

OFF-LOW-MED-HI options would be fantastic.
Title: Re: EEVBlog 121GW Discussion thread
Post by: mtdoc on January 23, 2018, 05:42:52 pm
Feature request

Could you include an option in the setup to disable the beeper? It's fine for power-on events and continuity testing etc... but it becomes more of an annoyance every time you turn the knob or press a button. I understand the reasoning behind it, but for me, I'd prefer to have the option to turn it off for key presses/mode changes (or at least select a lower volume).

OFF-LOW-MED-HI options would be fantastic.

Yes, please.  My wife just asked how often that was going to be beeping. Never had her ask that with another meter.  When I said I wasn't sure, she went in another room and closed the door. ::)

Add - now she just yelled at me through 2 sets of closed doors "make the beeping stop!  :rant:" 
Title: Re: EEVBlog 121GW Discussion thread
Post by: IanB on January 23, 2018, 05:50:12 pm
Can probably reprogram the beep with a pair of wire cutters  >:D
Title: Re: EEVBlog 121GW Discussion thread
Post by: mtdoc on January 23, 2018, 05:55:07 pm
Can probably reprogram the beep with a pair of wire cutters  >:D

Yes, I may have to resort to that. Otherwise my wife may reprogram it "up the side of my head"....
Title: Re: EEVBlog 121GW Discussion thread
Post by: Halcyon on January 23, 2018, 05:59:20 pm
Can probably reprogram the beep with a pair of wire cutters  >:D

Yes, I may have to resort to that. Otherwise my wife may reprogram it "up the side of my head"....

I just want to clarify, I want the beep on power-up and continuity, just no other time.
Title: Re: EEVBlog 121GW Discussion thread
Post by: mtdoc on January 23, 2018, 06:07:09 pm
Can probably reprogram the beep with a pair of wire cutters  >:D

Yes, I may have to resort to that. Otherwise my wife may reprogram it "up the side of my head"....

I just want to clarify, I want the beep on power-up and continuity, just no other time.

Yes, loss of continuity beep would be tragic - so the wire cutters will be held at bay for now.  I could tolerate the power on beep but I really don't want any of the other beeps though.   Volume control would also be good as you say.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on January 23, 2018, 06:26:02 pm
I have v1.04
Negative VA issue supposed to be fixed (haven't checked)
Beep is now off by default.
Ohms autoranging has been improved down to just under 4.5sec or so. They claim any faster and the meters would require recalibration. I don't know why they can't at least partially use the bargraph ADC for this.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Towger on January 23, 2018, 07:11:19 pm
I have v1.04
I don't know why they can't at least partially use the bargraph ADC for this.

Might be worth while getting David to have a good look at the code.  If it can be 'deciphered', with his strong maths background I am sure the algorithm can be improved/rewritten more.

Or just publish the code...

Is there going to be a solution to the wobbly knobs? [For those who already have a meter. ]
Title: Re: EEVBlog 121GW Discussion thread
Post by: hayatepilot on January 23, 2018, 08:34:30 pm
Ohms autoranging has been improved down to just under 4.5sec or so. They claim any faster and the meters would require recalibration. I don't know why they can't at least partially use the bargraph ADC for this.
Great news.  8)
Will it be further reduced for the 2nd batch? Calibration will not be a problem since it would be from the factory.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Halcyon on January 23, 2018, 08:53:54 pm
I have v1.04
Negative VA issue supposed to be fixed (haven't checked)
Beep is now off by default.
Ohms autoranging has been improved down to just under 4.5sec or so. They claim any faster and the meters would require recalibration. I don't know why they can't at least partially use the bargraph ADC for this.

Thanks Dave, is there an official support page for the 121GW where we can download vetted firmware and manuals etc... (past and latest versions)? I think a lot of us would be keen on updating as I think most (all?) were shipped with v1.01 to-date?
Title: Re: EEVBlog 121GW Discussion thread
Post by: GameProgrammer79 on January 23, 2018, 10:45:19 pm
Ohms autoranging has been improved down to just under 4.5sec or so. They claim any faster and the meters would require recalibration. I don't know why they can't at least partially use the bargraph ADC for this.
Great news.  8)
Will it be further reduced for the 2nd batch? Calibration will not be a problem since it would be from the factory.

The speed is basically based on algorithm used, a binary tree search would result in log(n) base2 where as linear (n). For example if linear search was taking 7 sec to reach extreme end (lowest range), then after binary search you can basically reduce time to 2.8 sec (log base 2 of 7 is 2.807355)

Now Dave is saying it is 4.5 sec, with a improved algorithm it can reduce to 2.16 sec. There are many ways to improve firmware speed, essentially they need to profile the code, reduce string copies if any, use all constant time data structures, remove unwanted calls to memory allocator (rather use object pools), check for cache hit analysis .. use simple array structures when possible and so on.

If they can install valgrind under quemu (if thats ported to STM32) you can do a much detailed profiling of the code. That way you can optimize the portions that are slowing down the meter. Not only it will make it run faster, it will also increase battery :)
Title: Re: EEVBlog 121GW Discussion thread
Post by: mikeselectricstuff on January 23, 2018, 10:48:34 pm
Ohms autoranging has been improved down to just under 4.5sec or so. They claim any faster and the meters would require recalibration. I don't know why they can't at least partially use the bargraph ADC for this.
Great news.  8)
Will it be further reduced for the 2nd batch? Calibration will not be a problem since it would be from the factory.

The speed is basically based on algorithm used, a binary tree search would result in log(n) base2 where as linear (n). For example if linear search was taking 7 sec to reach extreme end (lowest range), then after binary search you can basically reduce time to 2.8 sec (log base 2 of 7 is 2.807355)

Now Dave is saying it is 4.5 sec, with a improved algorithm it can reduce to 2.16 sec. There are many ways to improve firmware speed, essentially they need to profile the code, reduce string copies if any, use all constant time data structures, remove unwanted calls to memory allocator (rather use object pools), check for cache hit analysis .. use simple array structures when possible and so on.

If they can install valgrind under quemu (if thats ported to STM32) you can do a much detailed profiling of the code. That way you can optimize the portions that are slowing down the meter. Not only it will make it run faster, it will also increase battery :)
I suspect the limiting factor may be the time it takes to settle after re-ranging, rather than actual acquisition rate or any code speed limitations, though it may also be doing stupid things like excessive screen redraws
Title: Re: EEVBlog 121GW Discussion thread
Post by: HKJ on January 23, 2018, 11:15:40 pm
The speed is basically based on algorithm used, a binary tree search would result in log(n) base2 where as linear (n). For example if linear search was taking 7 sec to reach extreme end (lowest range), then after binary search you can basically reduce time to 2.8 sec (log base 2 of 7 is 2.807355)

You do not do a binary search on a multimeter.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Fungus on January 23, 2018, 11:43:51 pm
The speed is basically based on algorithm used, a binary tree search would result in log(n) base2 where as linear (n). For example if linear search was taking 7 sec to reach extreme end (lowest range), then after binary search you can basically reduce time to 2.8 sec (log base 2 of 7 is 2.807355)

It may not be possible to leap around randomly if there's much internal capacitance, etc.

The trick will be to short-circuit the A->D conversions and switch range as soon as possible when you see the range is obviously wrong (eg. look at the initial slope of the ADC charge curve?)

It may never be super-fast no matter what the firmware. It's easy to imagine clever tricks from the comfort of an armchair but the hardware is already built and you have to work with what you've got. eg. Looking at slopes sounds good but there may be too much variation between individual meters to make it reliable, or the ADC might not be suitable.

OTOH 4.5 seconds is a loooong time. I'd bet they're erring on the side of caution in the current firmware.

There are many ways to improve firmware speed, essentially they need to profile the code, reduce string copies if any, use all constant time data structures, remove unwanted calls to memory allocator (rather use object pools), check for cache hit analysis .. use simple array structures when possible and so on.

If they can install valgrind under quemu (if thats ported to STM32) you can do a much detailed profiling of the code. That way you can optimize the portions that are slowing down the meter. Not only it will make it run faster, it will also increase battery :)

None of that will be applicable here. It will be down to the hardware design, knowledge of the hardware, etc.
Title: Re: EEVBlog 121GW Discussion thread
Post by: glarsson on January 24, 2018, 12:02:00 am
The front end chip has a slow and a fast ADC. No need to figure out how to trick the slow if the fast is available. Is the fast ADC used for the bargraph?
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on January 24, 2018, 12:05:04 am
I suspect the limiting factor may be the time it takes to settle after re-ranging, rather than actual acquisition rate or any code speed limitations, though it may also be doing stupid things like excessive screen redraws

Yes, there will be some sort of chipset limit based on range switching and settling time. I don't know what that is.
I do know that Hycon recommended switching between constant voltage and constant current modes at the 500k range, so that may impact things.
I'm hoping that further tweaks are possible, and I've asked them to try some more, but it's almost certain we won't be able to magically get it to down to say 1 second.
There is likely a good reason why the Keysight U1282A isn't hugely faster using the same chipset.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on January 24, 2018, 12:06:44 am
The front end chip has a slow and a fast ADC. No need to figure out how to trick the slow if the fast is available. Is the fast ADC used for the bargraph?

Yes, and I have asked them to consider that.
Title: Re: EEVBlog 121GW Discussion thread
Post by: mikeselectricstuff on January 24, 2018, 12:09:32 am
Another data point : I have a meter here using the same chip that ranges from open to 0R in 2 seconds.
Title: Re: EEVBlog 121GW Discussion thread
Post by: HKJ on January 24, 2018, 12:12:50 am
The trick will be to short-circuit the A->D conversions and switch range as soon as possible when you see the range is obviously wrong (eg. look at the initial slope of the ADC charge curve?)

In ohm mode I can see two strategies:
1) Du a full measurement and select range depending on the result, this allows you to go down 3-4 decades at once.
2) Use the bargraph converter to change range, that is only on decade at a time.

Each range shift requires some settling time and I have no idea if 1) or 2) would be fastest.
Title: Re: EEVBlog 121GW Discussion thread
Post by: dr.diesel on January 24, 2018, 12:36:36 am
I'd like the option of recal to even further reduce the auto ranging time.   :-+
Title: Re: EEVBlog 121GW Discussion thread
Post by: dcac on January 24, 2018, 01:13:04 am
Another data point : I have a meter here using the same chip that ranges from open to 0R in 2 seconds.

Very interesting!

http://www.hycontek.com/wp-content/uploads/DS-HY3131_EN.pdf (http://www.hycontek.com/wp-content/uploads/DS-HY3131_EN.pdf)

I wonder what clock rate the HY3131 in 121GW is running? - typical is 4.9152MHz but max is 8.0MHz according to the datasheet. If higher clock rate would mean faster auto-ranging (my guess is that it would) but then also less battery life - I would really go for faster auto-range as long as the 121GW has a auto-power off function.

Title: Re: EEVBlog 121GW Discussion thread
Post by: glarsson on January 24, 2018, 02:18:26 am
One aspect of autoranging with a faster but lower precision ADC is that the meter might select a range that is not optimal. If for example the fast ADC measures 4.9999 as 5.04 it will select a range to high. More problematic is if the difference is the other way, then a low range is selected with overflow. The fast ADC could be tweaked to always read slightly too high.

This could be a user selected feature. Reasonable fast autoranging with precise range selection or very fast autoranging with imprecise range selection?
Title: Re: EEVBlog 121GW Discussion thread
Post by: Fungus on January 24, 2018, 02:34:39 am
One aspect of autoranging with a faster but lower precision ADC is that the meter might select a range that is not optimal.

You could always detect that and change range...  :popcorn:
Title: Re: EEVBlog 121GW Discussion thread
Post by: glarsson on January 24, 2018, 05:34:38 am
You could always detect that and change range...  :popcorn:
Yes, there are several options.
1. SLOW: Use the slow high precision ADC for ranging.
2. FAST: Use the fast low precision ADC for ranging, then switch to the high precision ADC and eventually make an additional step up or down.
3. EXTRA FAST: Use the fast low precision ADC for ranging. Use a slight offset to avoid over range.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on January 24, 2018, 09:41:55 am
I wonder what clock rate the HY3131 in 121GW is running? - typical is 4.9152MHz but max is 8.0MHz according to the datasheet. If higher clock rate would mean faster auto-ranging (my guess is that it would) but then also less battery life - I would really go for faster auto-range as long as the 121GW has a auto-power off function.

It's 4.9152MHz
And I don't think that's how it work, it doubt it would magically make the autoranging faster. The micro controls the autoranging, not the HY3131.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on January 24, 2018, 09:43:56 am
I'd like the option of recal to even further reduce the auto ranging time.   :-+

There are production meters in the field now, so we can't release firmware that would break the calibration, that would be very foolish.
Title: Re: EEVBlog 121GW Discussion thread
Post by: nidlaX on January 24, 2018, 09:44:55 am
How is the range switch modification going to be implemented? Who is doing the replacement for the US meters, and will you send replacement parts to customers who've already received theirs?
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on January 24, 2018, 09:51:16 am
Any news on the US meters?

Yes, sorry but the US meters will be delayed, they want to make some small tolerance changes to the range switch. We'd rather have them delayed a bit than to have any more potential range switch issues.
Title: Re: EEVBlog 121GW Discussion thread
Post by: dr.diesel on January 24, 2018, 10:02:39 am
I'd like the option of recal to even further reduce the auto ranging time.   :-+

There are production meters in the field now, so we can't release firmware that would break the calibration, that would be very foolish.

One would of-course put this FW behind a warning of such.  If the improvement is negligible then who cares, but if significant it would be a shame to censor it for those of us capable of a full cal, which could be quite a few as we now pass cal standards around.

All depends on how much improvement is hiding behind the recal FW, which might be ~2sec as Mike suggested, making it very worthwhile.
Title: Re: EEVBlog 121GW Discussion thread
Post by: mikeselectricstuff on January 24, 2018, 10:23:53 am
Any news on the US meters?

Yes, sorry but the US meters will be delayed, they want to make some small tolerance changes to the range switch. We'd rather have them delayed a bit than to have any more potential range switch issues.
Does the US batch include the EU ones that didn't pre-pay VAT? - ISTR you said some other countries were being fulfilled via US.
Title: Re: EEVBlog 121GW Discussion thread
Post by: dcac on January 24, 2018, 10:26:49 am
I wonder what clock rate the HY3131 in 121GW is running? - typical is 4.9152MHz but max is 8.0MHz according to the datasheet. If higher clock rate would mean faster auto-ranging (my guess is that it would) but then also less battery life - I would really go for faster auto-range as long as the 121GW has a auto-power off function.

It's 4.9152MHz
And I don't think that's how it work, it doubt it would magically make the autoranging faster. The micro controls the autoranging, not the HY3131.

Yeah you’re probably right, I notice now from the datasheet that range selection seems to be fully under software control by the MCU. So possibly only the actual ADC conversion would speed up with higher clock rate.

Great to see UEi responded so quickly and if  FW ver 1.04 achieved auto-ranging in 4.5 sec it’s a significant improvement over the 7.4 sec we saw before. More useful now for sure but still annoyingly slow. The prototype 121GW was 3.8 sec and U1282A about 3.0 sec in its fastmode, so there’s still room for improvement with a tweaked/hacked FW which I'm sure the programming wizards here at EEVblog eventually will provide.


Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on January 24, 2018, 11:02:05 am
Does the US batch include the EU ones that didn't pre-pay VAT? - ISTR you said some other countries were being fulfilled via US.

No, we shipped those from here.
Title: Re: EEVBlog 121GW Discussion thread
Post by: benst on January 24, 2018, 11:03:12 am
I see an app in the iOS App store called "EEVBlog 121GW" by Cheon Myoung-kun. That doesn't sound legit, does it?

And it looks bloody awfull.  :wtf:

Ben
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on January 24, 2018, 11:04:12 am
I'd like the option of recal to even further reduce the auto ranging time.   :-+

There are production meters in the field now, so we can't release firmware that would break the calibration, that would be very foolish.
One would of-course put this FW behind a warning of such.  If the improvement is negligible then who cares, but if significant it would be a shame to censor it for those of us capable of a full cal, which could be quite a few as we now pass cal standards around.

Almost all users do not have the ability to calibrate the meter themselves, and you would be effectively forcing those users to do that if they wanted to upgrade their firmware in the future. That would be very poor form.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on January 24, 2018, 11:05:13 am
I see an app in the iOS App store called "EEVBlog 121GW" by Cheon Myoung-kun. That doesn't sound legit, does it?
And it looks bloody awfull.  :wtf:

It is bloody awful which is why we wrote our own. But yes it is "legit". UEi got that person to write it.
Title: Re: EEVBlog 121GW Discussion thread
Post by: dr.diesel on January 24, 2018, 11:08:35 am
Almost all users do not have the ability to calibrate the meter themselves, and you would be effectively forcing those users to do that if they wanted to upgrade their firmware in the future. That would be very poor form.

I'm apparently communicating poorly, no worries.
Title: Re: EEVBlog 121GW Discussion thread
Post by: benst on January 24, 2018, 11:12:59 am
I see an app in the iOS App store called "EEVBlog 121GW" by Cheon Myoung-kun. That doesn't sound legit, does it?
And it looks bloody awfull.  :wtf:

It is bloody awful which is why we wrote our own. But yes it is "legit". UEi got that person to write it.

Ok, good to know, thanks! Any idea when your app will be ready for iOS?

Thanks,
Ben
Title: Re: EEVBlog 121GW Discussion thread
Post by: Kohanbash on January 24, 2018, 11:18:11 am
Any news on the US meters?

Yes, sorry but the US meters will be delayed, they want to make some small tolerance changes to the range switch. We'd rather have them delayed a bit than to have any more potential range switch issues.

Just to verify the Great Scott meters for the USA are getting the updated switch. Were they already manufactured (I thought they were sitting in a dock somewhere)?

(I am not rushing this, I am just curious)
Title: Re: EEVBlog 121GW Discussion thread
Post by: Scottjd on January 24, 2018, 11:21:30 am
Any news on the US meters?

Yes, sorry but the US meters will be delayed, they want to make some small tolerance changes to the range switch. We'd rather have them delayed a bit than to have any more potential range switch issues.

Ok, so your saying the meters are now in the US, and UEI is taking them to fix the range switches. Will UEI be shipping them, or will they get shipped again to the reshipper in the US and then make it to the customers. Or did you can the reshipper and UEI will be shipping the US meter now?

I have an idea, it’s not uncommon to have 2 different firmwares for different hardware releases.
As a “Thank you for being patient” can the US customers request maybe UEI can update the auto range speed on the US meters and mark them hardware version 1.1. Since it will be at the manufacturer I’m sure they can calibrate for the faster update ranging. Going forward for new batches can also all be marked as HW1.1 with the faster range update.
It will only make it a better product with future sales of the meters. And I’m sure someone will review it with the faster update range showing the meter with all the bugs fixed as well. And this way you get some of the faster update meters in people’s hands to work out any bug that might inadvertently happen from the faster update range improvements for hands on testing.

And for those that have the ability to calibrate the meter they can also load hardware version 1.1 firmware and do the calibration themselves.

If an open source firmware does happen, then who ever is working on the firmware will need to be aware of the different hardware versions.  This is a common thing when hardware changes happen anyway.


Title: Re: EEVBlog 121GW Discussion thread
Post by: mikeselectricstuff on January 24, 2018, 11:47:03 am
Presumably the cal issue is that they need to do measurement differently, so different cal data is needed.

This could be handled by the firmware looking to see if the new format data is present, and only using the newer ranging method if so. A user could choose to recal to enable this if they have the facility.

Another approach for a user to recal would be simply to use old FW to set a multiturn trimmer to the required cal value, update the FW, then use the trimmer to recal.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Halcyon on January 24, 2018, 11:47:20 am
How is the range switch modification going to be implemented? Who is doing the replacement for the US meters, and will you send replacement parts to customers who've already received theirs?

Dave has answered this in the "Issues" thread, see below...

The switch on my meter (#000499) is also wobbly and has the problem described here.
I took it apart, and contacts and pcb looked ok. After I put it back together it worked allright for a while, but now it's back and I have to fiddle with the switch again to get it to display correct readings. :-BROKE
Dave, once UEi figures out a fix, will you send out a replacement part?

Yes we'll have to do that for those existing shipments who have problems.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Scottjd on January 24, 2018, 12:22:01 pm
Presumably the cal issue is that they need to do measurement differently, so different cal data is needed.

This could be handled by the firmware looking to see if the new format data is present, and only using the newer ranging method if so. A user could choose to recal to enable this if they have the facility.

Another approach for a user to recal would be simply to use old FW to set a multiturn trimmer to the required cal value, update the FW, then use the trimmer to recal.

True, but just because a meter is calibrated again doesn’t mean the format of the cal data stored in the eeprom is going to be in a different format. Assuming it will be the same formate, just different numbers to the firmware to read I not sure the firmware could determine what is an old cal data vs re-cal for the faster  update rate. And then theirs the issue of space, adding extra code if timcoild determine the difference between new and old cal data woild take up more space. And we don’t know how much is available as it currently is.
Besides, my thought behind it was technical the updated switch is a hardware change also. They would need someway to mark what meters have the updated switch bs the older one. This way if the issue comes up again they will know if it was an older meter first batch, or a fixed one that the problem re-surfaced on.
I guess when others get the parts to fix it themselves thenpart bag might want to include a self repair sticker unless UEI plans to stamp the under side of the switch with s different code or add a code to the mold?
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on January 24, 2018, 12:24:28 pm
Ok, so your saying the meters are now in the US, and UEI is taking them to fix the range switches. Will UEI be shipping them, or will they get shipped again to the reshipper in the US and then make it to the customers. Or did you can the reshipper and UEI will be shipping the US meter now?

They will now ship direct from Kane Test (UEi) in the US.

Quote
I have an idea, it’s not uncommon to have 2 different firmwares for different hardware releases.
As a “Thank you for being patient” can the US customers request maybe UEI can update the auto range speed on the US meters and mark them hardware version 1.1. Since it will be at the manufacturer I’m sure they can calibrate for the faster update ranging. Going forward for new batches can also all be marked as HW1.1 with the faster range update.

There is no change in actual PCB hardware, it's a small mod to the tolerance range switch parts.

Quote
And for those that have the ability to calibrate the meter they can also load hardware version 1.1 firmware and do the calibration themselves.

I've said this before, we will not release firmware that requires a recal. Most people are NOT  in a position to calibrate their own meters.
To do so would require screwing existing customers, or maintaining two version of the firmware. Either solution is not acceptable.
Title: Re: EEVBlog 121GW Discussion thread
Post by: dcac on January 24, 2018, 12:44:28 pm
Another approach for a user to recal would be simply to use old FW to set a multiturn trimmer to the required cal value, update the FW, then use the trimmer to recal.

That would also make a great video for Dave to show this procedure.

But I can see Dave’s problem - from the manual: “Factory calibration will be VOID if this function is used”

So that warranty will be lost on the already delivered units. So I guess then the only way is to issue a recall and who's going to cover that cost? If spread out over all backers (who bought a 121GW) what money are we talking about?

Title: Re: EEVBlog 121GW Discussion thread
Post by: hwti on January 24, 2018, 12:49:57 pm
Dave posted the schematic in the firmware thread, but I reply here since my questions would be off-topic there :
Here is the schematic which may help
David2 is working on seeing what we can provide in terms of documentation to help people who want to write their own firmware.
http://www.eevblog.com/files/121GW%20EEVBlog%20Circuit%20diagram.pdf (http://www.eevblog.com/files/121GW%20EEVBlog%20Circuit%20diagram.pdf)
Why are Q13/Q16 (and Q14/Q15 if they were populated) used ?
To set the power-on (floating GPIO ?) state, a pull-up resistor would be enough.
The invert could have been done in software.

What would the B/Y channel of U14 would do if it was connected ?
It would connect TP11 to TP13 if DCmV_CTL (not used elsewhere) is high :-//

Is it safe to let 4053 logic input pins floating (C pin of U11, A pin of U14 if it was populated) ?
Usually it's not recommended, so unless the 4053 is special it's strange.
Title: Re: EEVBlog 121GW Discussion thread
Post by: logictom on January 24, 2018, 01:21:24 pm
Regarding the specs of the meter, in the manual it lists the ranges:

(https://www.eevblog.com/forum/testgear/eevblog-121gw-discussion-thread/?action=dlattach;attach=389136)

So what is the resolution and accuracy for 501uA to 4999uA?
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on January 24, 2018, 01:40:00 pm
Regarding the specs of the meter, in the manual it lists the ranges:

(https://www.eevblog.com/forum/testgear/eevblog-121gw-discussion-thread/?action=dlattach;attach=389136)

So what is the resolution and accuracy for 501uA to 4999uA?

They use the 5mA range.
Title: Re: EEVBlog 121GW Discussion thread
Post by: IanB on January 24, 2018, 02:06:13 pm
In other words, the table is like this: (?)

Range    Resolution, Accuracy  Burden Voltage
50 µA    1 nA, ±1.5%+15  100 µV/µA
500 µA    10 nA, ±1.5%+15  100 µV/µA
5 mA    0.1 µA, ±0.25%+5  2 mV/mA
50 mA    1 µA, ±0.25%+5  2 mV/mA
0.5 A    10 µA, ±0.75%+15  0.03 V/A
10 A    1 mA, ±0.75%+15  0.03 V/A
Title: Re: EEVBlog 121GW Discussion thread
Post by: hwti on January 24, 2018, 02:36:49 pm
Dave, http://www.eevblog.com/files/121GW%20EEVBlog%20Circuit%20diagram.pdf (http://www.eevblog.com/files/121GW%20EEVBlog%20Circuit%20diagram.pdf) is rev 1752, and my actual meter is rev 1745 on the PCB.
Are there any différences ?

The rev 1705 and 1720 from your "121GW Final Test Unit Inspection" video had U14 for example.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Scottjd on January 24, 2018, 04:10:54 pm
The rev 1705 and 1720 from your "121GW Final Test Unit Inspection" video had U14 for example.
Are you referring to the video with them all on the table, and the close up shots? I saw that one as 1745 with u14 missing also. Or are you referring to another video?
Title: Re: EEVBlog 121GW Discussion thread
Post by: logictom on January 24, 2018, 04:45:00 pm
Regarding the specs of the meter, in the manual it lists the ranges:

(https://www.eevblog.com/forum/testgear/eevblog-121gw-discussion-thread/?action=dlattach;attach=389136)

So what is the resolution and accuracy for 501uA to 4999uA?

They use the 5mA range.

If that is the case, why is it listed as 5 to 50 mA instead of that actual range of 0.5 to 50mA? Am I missing something simple here? ???
Title: Re: EEVBlog 121GW Discussion thread
Post by: amspire on January 24, 2018, 04:55:01 pm
Regarding the specs of the meter, in the manual it lists the ranges:

(https://www.eevblog.com/forum/testgear/eevblog-121gw-discussion-thread/?action=dlattach;attach=389136)

So what is the resolution and accuracy for 501uA to 4999uA?

They use the 5mA range.

If that is the case, why is it listed as 5 to 50 mA instead of that actual range of 0.5 to 50mA? Am I missing something simple here? ???
You are missing something. Multimeter specifications always refer to the ranges - not to currents or voltages you are measuring. So this table is talking about the 50uA to 10A ranges.

If you want to measure 500uA, you can use the 500uA range, the 5mA range, the 50mA range, the 0.5A range, or the 5A range. The 10A is just a bit too far to see the 500uA. Each of these ranges will have its own accuracy that you can read from the table.

Why would you want to measure 500uA on the 0.5A range? The reason would be the burden voltage. For that range, the voltage drop across the multimeter (ignoring the 10A fuse) is 0.03V/A or at 500uA, that is only 15uV! The accuracy of the 500uV measurement would only be about 30%, but that can often be good enough.
Title: Re: EEVBlog 121GW Discussion thread
Post by: hwti on January 24, 2018, 05:28:42 pm
The rev 1705 and 1720 from your "121GW Final Test Unit Inspection" video had U14 for example.
Are you referring to the video with them all on the table, and the close up shots? I saw that one as 1745 with u14 missing also. Or are you referring to another video?
The video I'm referring to is unlisted, but easy to find by its title.
But those older revision don't really matter, it's just to show there are differences, and not limited to the changes needed to pass certification.

What matters is we have rev 1745 meters, so perhaps we need rev 1745 schematic, and not rev 1752 which might be different.
Title: Re: EEVBlog 121GW Discussion thread
Post by: amspire on January 24, 2018, 05:34:22 pm
The rev 1705 and 1720 from your "121GW Final Test Unit Inspection" video had U14 for example.
Are you referring to the video with them all on the table, and the close up shots? I saw that one as 1745 with u14 missing also. Or are you referring to another video?
The video I'm referring to is unlisted, but easy to find by its title.
But those older revision don't really matter, it's just to show there are differences, and not limited to the changes needed to pass certification.

What matters is we have rev 1745 meters, so perhaps we need rev 1745 schematic, and not rev 1752 which might be different.
Dave did say that they had to tidy up the schematic before they could release it. When you tidy up a document, that is a change and so the revision must increase. We do not know why the tidy up was needed - it might be just removing confidential information like employees names.

The circuit will be either accurate, or pretty close to accurate.

Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on January 24, 2018, 05:36:04 pm
The circuit will be either accurate, or pretty close to accurate.

I am told that schematic is accurate to the shipped hardware.
Title: Re: EEVBlog 121GW Discussion thread
Post by: firewalker on January 24, 2018, 06:06:49 pm
The meters of "Johnie be good" for Europe via the Germany company, will include the switch tweak?

Alexander.
Title: Re: EEVBlog 121GW Discussion thread
Post by: JacquesBBB on January 24, 2018, 06:09:12 pm
How does the 121GW meter compare to the micro current ?

Is the micro current still useful for those who have the meter ?
Title: Re: EEVBlog 121GW Discussion thread
Post by: ChrisG on January 24, 2018, 06:12:34 pm
Thank you for the diagram! Some of the parts are not specified or listed in a separate table. Is this on purpose?
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on January 24, 2018, 06:15:34 pm
The meters of "Johnie be good" for Europe via the Germany company, will include the switch tweak?

Yes, all future meters shipped will have the revised switch
Title: Re: EEVBlog 121GW Discussion thread
Post by: FrankBuss on January 24, 2018, 06:15:57 pm
Presumably the cal issue is that they need to do measurement differently, so different cal data is needed.

This could be handled by the firmware looking to see if the new format data is present, and only using the newer ranging method if so. A user could choose to recal to enable this if they have the facility.

Another approach for a user to recal would be simply to use old FW to set a multiturn trimmer to the required cal value, update the FW, then use the trimmer to recal.

Right, no need to maintain two different firmware versions, just a small portion of the firmware has to handle the old and new format. I hope they are experienced firmware developers who versioned the calibration data, because such things always change. But even if they didn't, it shouldn't be a problem: just use something impossible for the old format as the first byte for the new calibration data, to mark it as the new format. Fortunately it doesn't have to be compatible in the other direction, like there is nobody who would use a new set of calibration data with the old firmware. Could be programmed in like an hour.
Title: Re: EEVBlog 121GW Discussion thread
Post by: ChrisG on January 24, 2018, 06:19:00 pm
@DaveJ: will you publish a list at a certain moment which lists the confirmed issues? And which ones can be solved by firmware updates? The issues thread does not seem to have many more new issues coming in so I assume we've captured 90-95% of them by now.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on January 24, 2018, 06:22:36 pm
Right, no need to maintain two different firmware versions, just a small portion of the firmware has to handle the old and new format. I hope they are experienced firmware developers who versioned the calibration data, because such things always change. But even if they didn't, it shouldn't be a problem: just use something impossible for the old format as the first byte for the new calibration data, to mark it as the new format. Fortunately it doesn't have to be compatible in the other direction, like there is nobody who would use a new set of calibration data with the old firmware. Could be programmed in like an hour.

It might not be that easy.
It might affect calibration of other ranges, because (guessing) it might use a common ADC read averaging routine or something. What if you have to recalibrate the whole meter.
I really think this is bad idea and I am loath to recommend such a thing.

Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on January 24, 2018, 06:23:04 pm
@DaveJ: will you publish a list at a certain moment which lists the confirmed issues?

Yes.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Towger on January 24, 2018, 06:40:59 pm


To do so would require screwing existing customers, or maintaining two version of the firmware. Either solution is not acceptable.

At worse they just don't update beyond the version of firmware their meter supports.  If the the calibration data structure was well designed it should contain the initial firmware/hardware version it is for.  Newer firmware should be able to check it and decide it is is going to display a meaningful error or use the old method etc.  If they don't currently embed a version number it can be added to the new firmware etc.

At the end of the day if the meter is slow it will greatly impact future sales.
Title: Re: EEVBlog 121GW Discussion thread
Post by: hwti on January 24, 2018, 06:59:54 pm
Thank you for the diagram! Some of the parts are not specified or listed in a separate table. Is this on purpose?
AFAIK, the components with an "x" value aren't populated on the PCB.
Some were probably added to allow to change the circuit in case of issues, or to be able to do some tests.
Others like U14 have been used in previous revisions and were removed (even if they didn't plan to reuse it, it's perhaps easier to avoid rerouting the PCB).
For example :
 - adding R142/C108 (and all the others) would do hardware debouncing on the keys (it's probably done in the firmware instead)
 - removing R101/R102 and adding R133 would switch to the AD8436 OUT without the OUTBUF follower
 - many 0 ohm resistor could be removed if someone wanted to test individual components for any reason
Title: Re: EEVBlog 121GW Discussion thread
Post by: exe on January 24, 2018, 11:28:25 pm
Does hardware let simultaneous measurement of AC and DC voltage? (I want to measure AC and DC bias at the same time)

Is it possible to do faster sampling at the expense of accuracy/resolution?
Title: Re: EEVBlog 121GW Discussion thread
Post by: imidis on January 24, 2018, 11:42:19 pm
At the end of the day if the meter is slow it will greatly impact future sales.
I think this is a very good point. To hinder performance for all future meters doesn't seem the best decision either.

Title: Re: EEVBlog 121GW Discussion thread
Post by: Iagash on January 25, 2018, 12:14:49 am
So the Bluetooth Module is not used in the released meter.   :-DD

Well, yes if you look at the bluetooth protocol and the transmission, this feels true. ;-)
Title: Re: EEVBlog 121GW Discussion thread
Post by: Iagash on January 25, 2018, 12:28:31 am
At the end of the day if the meter is slow it will greatly impact future sales.
I think this is a very good point. To hinder performance for all future meters doesn't seem the best decision either.

I would also think about this a little longer. We are talking about 500 meters now. Is it worth to settle for a second choice solution for the rest of the product live or even maybe fix it now before the Jonny be Good batch is shipped and only have to deal with the small amount that is in the wild? Maybe even fix it for the US meters and you reduce the number even further? What would be the cost for an recalibration offer for the existing meters and what would be the sales impact in the future on the product? What would be the cost of maintaining two firmware versions? I don't know the answers but it's something to think about at this point of the live cycle of the meter.
Title: Re: EEVBlog 121GW Discussion thread
Post by: mikeselectricstuff on January 25, 2018, 12:40:33 am
Right, no need to maintain two different firmware versions, just a small portion of the firmware has to handle the old and new format. I hope they are experienced firmware developers who versioned the calibration data, because such things always change. But even if they didn't, it shouldn't be a problem: just use something impossible for the old format as the first byte for the new calibration data, to mark it as the new format. Fortunately it doesn't have to be compatible in the other direction, like there is nobody who would use a new set of calibration data with the old firmware. Could be programmed in like an hour.

It might not be that easy.
It might affect calibration of other ranges, because (guessing) it might use a common ADC read averaging routine or something. What if you have to recalibrate the whole meter.
I really think this is bad idea and I am loath to recommend such a thing.
I think you need to find out more details of the exact reason - maybe "require recal" just means "requires rewriting code we can't be arsed to do"
Title: Re: EEVBlog 121GW Discussion thread
Post by: exe on January 25, 2018, 01:00:10 am
Concerning calibration, may be just implement import of it in, say, json or csv?
Title: Re: EEVBlog 121GW Discussion thread
Post by: fboehle on January 25, 2018, 01:06:11 am
How does it actually function with so many different grounds. From what I can tell, most of the grounds are not directly connected to each other, but at the same time a large potential difference would certainly blow up some ICs. So how is their potential brought close together?

(I couldn't find a connection between AGND, GND, VSS)
Title: Re: EEVBlog 121GW Discussion thread
Post by: Fungus on January 25, 2018, 01:31:49 am
a large potential difference would certainly blow up some ICs.

The meter is battery powered and the only connection to the outside world is the input jacks. Where would a large potential difference come from?

Title: Re: EEVBlog 121GW Discussion thread
Post by: Kean on January 25, 2018, 01:54:01 am
I wonder if someone could check the meter in the LowZ mode.   In the early unit, if I applied a 1VRMS 60Hz signal, the meter would read zero as expected.   However, when I would increase the frequency to 389KHz, the meter was displaying 181.3 volts even though there was still only a volt being supplied.   There was something strange going on with it that I never looked into.  I reported the problem when I discovered it but with as many problems that the meter still has, I wonder if this was addressed in the released version.

Joe, I can confirm this issue is still present in FW1.01.
I generated a 2.8Vpp 60Hz (& 1kHz) sine wave with my MSO1104Z-S and it read 0V in LowZ mode.
When I upped the freq to 389kHZ and I got a reading of 189.2Vac.  See photo...

Edit: and it correctly read ~1V AC without LowZ up to maybe 100kHz, but that dropped to 0.773V AC at 389kHz
Title: Re: EEVBlog 121GW Discussion thread
Post by: maukka on January 25, 2018, 01:54:55 am
I wonder if someone could check the meter in the LowZ mode.   In the early unit, if I applied a 1VRMS 60Hz signal, the meter would read zero as expected.   However, when I would increase the frequency to 389KHz, the meter was displaying 181.3 volts even though there was still only a volt being supplied.

With a 1Vrms signal the LowZ mode stays at 0V until 28kHz where it jumps to 10.4V. At 389kHz it shows 195.7V. This on v1.01.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Towger on January 25, 2018, 02:26:02 am
I think you need to find out more details of the exact reason - maybe "require recal" just means "requires rewriting code we can't be arsed to do"

Probably true 'can't be arsed' programmers are very common   :-\
Title: Re: EEVBlog 121GW Discussion thread
Post by: tpw_rules on January 25, 2018, 03:29:11 am
I don't buy the 'requiring recal' excuse either.

The meter has three sources of autocalibration delay. The first is an enforced delay on changing mode or range, which depends on the switch that was performed. When this delay is active, the display is blanked and the autocalibration routine does not run. The second is a sample averager, which is 8 samples for OHMS range and 16 for every other. This average value controls the screen display, and the current sample controls the bargraph. The same calibration factors are applied to both numbers. The third is a rolling average applied to the screen display, which depends on the mode and range as well. This should not be a factor, as the average resets on overrange or a large measurement delta.

The autorange is performed on the final displayed screen number that you see, after all three sources have been factored in. There is little to no software or calibration reason they couldn't shorten the delay during autoranging (which is what I think the v1.04 firmware does) or use the bargraph value initially. The calibration factor applied is the same for both measurements.

I've made a patch which removes that mode/range change delay while autoranging, but I can't test it without a meter. I'm now wondering if anybody would be willing to sell me their meter for testing purposes?
Title: Re: EEVBlog 121GW Discussion thread
Post by: dcac on January 25, 2018, 03:43:36 am
Dave posted the schematic in the firmware thread, but I reply here since my questions would be off-topic there :
Here is the schematic which may help
http://www.eevblog.com/files/121GW%20EEVBlog%20Circuit%20diagram.pdf (http://www.eevblog.com/files/121GW%20EEVBlog%20Circuit%20diagram.pdf)
Is it safe to let 4053 logic input pins floating (C pin of U11, A pin of U14 if it was populated) ?
Usually it's not recommended, so unless the 4053 is special it's strange.

Yes that seems strange - C is pin9 on U11 and is a digital cmos input and really shouldn't be left floating. Schematics error? should it be connected to A and B which already are connected together.

Title: Re: EEVBlog 121GW Discussion thread
Post by: exe on January 25, 2018, 08:02:44 am
I've made a patch which removes that mode/range change delay while autoranging, but I can't test it without a meter. I'm now wondering if anybody would be willing to sell me their meter for testing purposes?

Well, I have two, I can sell one. It cost me ~194 euros each delivered (I had to pay VAT and "processing" fee), I ask 180euro+delivery. The one I can sell was never used except a few power ups just to check. Please let me know (here or PM) if you are interested.

PS did other guys from EU also paid VAT? I though it supposed to be delivered from Germany via a distributor...

EDIT: I calculated price wrong first time.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Smokey on January 25, 2018, 08:32:53 am
Oh man... can't wait for firmware version ...

v1.21

I hope it includes some serious shit!
Title: Re: EEVBlog 121GW Discussion thread
Post by: hwti on January 25, 2018, 08:35:46 am
Yes that seems strange - C is pin9 on U11 and is a digital cmos input and really shouldn't be left floating. Schematics error? should it be connected to A and B which already are connected together.
I don't see any obvious trace connected to the pin.
I didn't want to reopen the whole meter, but by just removing the backcover the pin is accessible : I measured 13MOhm to ground, so it really seems to be floating (so no connection to ground under the chip, which could have been another option).
Title: Re: EEVBlog 121GW Discussion thread
Post by: dr.diesel on January 25, 2018, 08:44:37 am
Oh man... can't wait for firmware version ...

v1.21

I hope it includes some serious shit!

I just about spilled my Beer, well done Sir. 
Title: Re: EEVBlog 121GW Discussion thread
Post by: logictom on January 25, 2018, 10:24:37 am
You are missing something. Multimeter specifications always refer to the ranges - not to currents or voltages you are measuring. So this table is talking about the 50uA to 10A ranges.

Thanks amspire, that makes sense and it is what I see in the manual for my fluke, but what I still don't get is, why is the range specified with the lower value, so the 5mA value, when it can measure down to 500uA?
Title: Re: EEVBlog 121GW Discussion thread
Post by: Kal on January 25, 2018, 10:26:45 am
Just want to add that rotary switch wobble issue exists also with my meter (EU shipped). https://youtu.be/pjaWWMoPMsE
Is this same for everyone or only part of the already shipped meters?
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on January 25, 2018, 10:45:18 am
I've made a patch which removes that mode/range change delay while autoranging, but I can't test it without a meter. I'm now wondering if anybody would be willing to sell me their meter for testing purposes?

If you upload the firmware file then we can test it.
I'd get you a meter, but we only have two production units left here.
Title: Re: EEVBlog 121GW Discussion thread
Post by: fboehle on January 25, 2018, 10:45:26 am
You are missing something. Multimeter specifications always refer to the ranges - not to currents or voltages you are measuring. So this table is talking about the 50uA to 10A ranges.

Thanks amspire, that makes sense and it is what I see in the manual for my fluke, but what I still don't get is, why is the range specified with the lower value, so the 5mA value, when it can measure down to 500uA?
Ranges on multimeters are always specified with the upper limit. The lower limit is always 0. So with the 5V range you can measure from 0V to +-5V. But to get a meaningful measurement, you need to have enough resolution to discern values at the lower end. A 50000 count DMM, like this one, will have a resolution of 0.0001V or 100 uV on the 5V range. So you can measure only discrete values from 0 to +-5V in 100uV steps.
Title: Re: EEVBlog 121GW Discussion thread
Post by: IanB on January 25, 2018, 10:57:56 am
Thanks amspire, that makes sense and it is what I see in the manual for my fluke, but what I still don't get is, why is the range specified with the lower value, so the 5mA value, when it can measure down to 500uA?

Please see my reply from above, reproduced below.

The table is really listing each of the independent ranges and their attributes, like this:

Range    Resolution, Accuracy  Burden Voltage
50 µA    1 nA, ±1.5%+15  100 µV/µA
500 µA    10 nA, ±1.5%+15  100 µV/µA
5 mA    0.1 µA, ±0.25%+5  2 mV/mA
50 mA    1 µA, ±0.25%+5  2 mV/mA
0.5 A    10 µA, ±0.75%+15  0.03 V/A
10 A    1 mA, ±0.75%+15  0.03 V/A

As per usual, you would pick the lowest range suitable for the value you wish to measure.

Title: Re: EEVBlog 121GW Discussion thread
Post by: tpw_rules on January 25, 2018, 03:27:11 pm
I've made a patch which removes that mode/range change delay while autoranging, but I can't test it without a meter. I'm now wondering if anybody would be willing to sell me their meter for testing purposes?

If you upload the firmware file then we can test it.
I'd get you a meter, but we only have two production units left here.

Sure, as long as I'm not responsible for any possible bodily harm as a result :) And thanks for the note, I do understand you need to keep those. But I leave the country in a month and I'm worried I won't get a meter before then as I'm in the US group. I'd really like one to continue hacking on, it's been fun so far.

For the patch, I just made the autorange routine ignore the mode/range change delay if the last mode/range change was caused by autoranging. It might just oscillate wildly, who knows! If it does work, it could more than halve autorange time.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on January 25, 2018, 07:15:31 pm
I've made a patch which removes that mode/range change delay while autoranging, but I can't test it without a meter. I'm now wondering if anybody would be willing to sell me their meter for testing purposes?

If you upload the firmware file then we can test it.
I'd get you a meter, but we only have two production units left here.

Sure, as long as I'm not responsible for any possible bodily harm as a result :) And thanks for the note, I do understand you need to keep those. But I leave the country in a month and I'm worried I won't get a meter before then as I'm in the US group. I'd really like one to continue hacking on, it's been fun so far.

For the patch, I just made the autorange routine ignore the mode/range change delay if the last mode/range change was caused by autoranging. It might just oscillate wildly, who knows! If it does work, it could more than halve autorange time.

Works!  :clap:
I compared UEi's v1.04 and it's only a smidgen slower, not even half a second.

https://www.youtube.com/watch?v=3MD88EYLdQQ (https://www.youtube.com/watch?v=3MD88EYLdQQ)
Title: Re: EEVBlog 121GW Discussion thread
Post by: ChrisG on January 25, 2018, 07:27:45 pm
I've made a patch which removes that mode/range change delay while autoranging, but I can't test it without a meter. I'm now wondering if anybody would be willing to sell me their meter for testing purposes?

If you upload the firmware file then we can test it.
I'd get you a meter, but we only have two production units left here.

Sure, as long as I'm not responsible for any possible bodily harm as a result :) And thanks for the note, I do understand you need to keep those. But I leave the country in a month and I'm worried I won't get a meter before then as I'm in the US group. I'd really like one to continue hacking on, it's been fun so far.

For the patch, I just made the autorange routine ignore the mode/range change delay if the last mode/range change was caused by autoranging. It might just oscillate wildly, who knows! If it does work, it could more than halve autorange time.

Works!  :clap:
I compared UEi's v1.04 and it's only a smidgen slower, not even half a second.

https://www.youtube.com/watch?v=3MD88EYLdQQ (https://www.youtube.com/watch?v=3MD88EYLdQQ)


NICE!!!!  :-+ :-+ :-+ :-+
Title: Re: EEVBlog 121GW Discussion thread
Post by: FrankBuss on January 25, 2018, 07:29:17 pm
The company should hire tpw_rules. Pretty amazing to hack the binary without the source code and not even a meter for testing. Imagine what he could do if he would have the hardware and the source code :)
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on January 25, 2018, 07:42:42 pm
The company should hire tpw_rules. Pretty amazing to hack the binary without the source code and not even a meter for testing. Imagine what he could do if he would have the hardware and the source code :)

Indeed, thoroughly impressed!  :-+
Title: Re: EEVBlog 121GW Discussion thread
Post by: AgiRigSig on January 25, 2018, 07:47:57 pm
Wow, I am deeply impressed. As Frank already wrote,  UEI should hire tpw_rules  :-+ :-+ :-+
Title: Re: EEVBlog 121GW Discussion thread
Post by: mikeselectricstuff on January 25, 2018, 08:58:19 pm
I've made a patch which removes that mode/range change delay while autoranging, but I can't test it without a meter. I'm now wondering if anybody would be willing to sell me their meter for testing purposes?

If you upload the firmware file then we can test it.
I'd get you a meter, but we only have two production units left here.

Sure, as long as I'm not responsible for any possible bodily harm as a result :) And thanks for the note, I do understand you need to keep those. But I leave the country in a month and I'm worried I won't get a meter before then as I'm in the US group. I'd really like one to continue hacking on, it's been fun so far.

For the patch, I just made the autorange routine ignore the mode/range change delay if the last mode/range change was caused by autoranging. It might just oscillate wildly, who knows! If it does work, it could more than halve autorange time.

Works!  :clap:
I compared UEi's v1.04 and it's only a smidgen slower, not even half a second.

https://www.youtube.com/watch?v=3MD88EYLdQQ (https://www.youtube.com/watch?v=3MD88EYLdQQ)
It's clearly doing some stuff it doesn't need to though - you see some intermediate displays during ranging
Title: Re: EEVBlog 121GW Discussion thread
Post by: ChrisG on January 25, 2018, 09:18:21 pm
I've made a patch which removes that mode/range change delay while autoranging, but I can't test it without a meter. I'm now wondering if anybody would be willing to sell me their meter for testing purposes?

If you upload the firmware file then we can test it.
I'd get you a meter, but we only have two production units left here.

Sure, as long as I'm not responsible for any possible bodily harm as a result :) And thanks for the note, I do understand you need to keep those. But I leave the country in a month and I'm worried I won't get a meter before then as I'm in the US group. I'd really like one to continue hacking on, it's been fun so far.

For the patch, I just made the autorange routine ignore the mode/range change delay if the last mode/range change was caused by autoranging. It might just oscillate wildly, who knows! If it does work, it could more than halve autorange time.

Works!  :clap:
I compared UEi's v1.04 and it's only a smidgen slower, not even half a second.

https://www.youtube.com/watch?v=3MD88EYLdQQ (https://www.youtube.com/watch?v=3MD88EYLdQQ)
It's clearly doing some stuff it doesn't need to though - you see some intermediate displays during ranging

Indeed Mike next to that I'm wondering if the v1.04 version can not be released to this group to try, test and give feedback.
Title: Re: EEVBlog 121GW Discussion thread
Post by: bicycleguy on January 27, 2018, 05:04:38 am
The company should hire tpw_rules. Pretty amazing to hack the binary without the source code and not even a meter for testing. Imagine what he could do if he would have the hardware and the source code :)
NO !   NO !  NO !     Don't let UEI steel him.  tow_rules should stay on the open source side and help us to not only get a more awesome meter but understand how it works!  I am really impressed :)
Title: Re: EEVBlog 121GW Discussion thread
Post by: Candid on January 27, 2018, 07:40:05 am
I am having problems with connecting the 121GW app from dave2. I did no get any data shown in the app up to now. Most time it even does not connect.

I first run bluetooth and connect to the 121GW then I start the app. Sometimes when I click on refresh I can see the 121GW. Only one time it was able to connect (but no data shown, only white screen). Most time it says "connecting..." but never does.

The other app "EEVBlog 121GW" sometimes connects successfully and shows some values but sorry, it's so ugly.

/EDIT:
Now I got it running for one time but I think I am missing some data on the screen?
Title: Re: EEVBlog 121GW Discussion thread
Post by: plexus on January 28, 2018, 06:39:30 am
Unforunately I immersed myself in the Apple eco-sh*thole starting in 1981. So I have macOS and iOS crap now. Eventually I will migrate away from all that.

But for now, where can I find updates on iOS/macOS software for the 121GW? I found the UEI iOS app and it works ok.

Is there somewhere where Dave is keeping us updated on software status? Or do I have to follow a thread?

Thanks!
Title: Re: EEVBlog 121GW Discussion thread
Post by: gnavigator1007 on January 28, 2018, 07:22:38 am
 Acts like everything is fine set on volts with both leads plugged in A/mA
Title: Re: EEVBlog 121GW Discussion thread
Post by: tpw_rules on January 28, 2018, 07:37:24 am
Acts like everything is fine set on volts with both leads plugged in A/mA

Strange.  Maybe someone missed an OR statement.  Just an added bit of info, both the Fluke 189 and Brymen BM869s will fault out under this condition.

Yup, they missed it. Code is here (https://github.com/tpwrules/121gw-re/blob/e0a0d88c952e8e1e61eedb4d6fb0b3b62a58be6a/database/EEVBlog-102.c#L14754). v0 is 0 if nothing's plugged in, 1 if mA is, 2 if A is, and 3 if both. They assume everything is OK if 0, or if 3. Maybe the hardware won't do the correct thing in case both are plugged in so they didn't check. I don't really understand how it's sensing a plug.
Title: Re: EEVBlog 121GW Discussion thread
Post by: bicycleguy on January 28, 2018, 12:10:05 pm
...
Yup, they missed it. Code is here (https://github.com/tpwrules/121gw-re/blob/e0a0d88c952e8e1e61eedb4d6fb0b3b62a58be6a/database/EEVBlog-102.c#L14754). v0 is 0 if nothing's plugged in, 1 if mA is, 2 if A is, and 3 if both. They assume everything is OK if 0, or if 3. Maybe the hardware won't do the correct thing in case both are plugged in so they didn't check. I don't really understand how it's sensing a plug.

From the schematic it looks like the mA and A input terminals are physically split with part pulled up to Vdd through ~30M res.  Inserting a lead shorts the split to the respective amps shunt to ground and op-amps sense and condition signal to the STM.  Just my speculation though, my meter arrives in March :'(
Title: Re: EEVBlog 121GW Discussion thread
Post by: Candid on January 28, 2018, 10:48:09 pm
Just tested it. AUTO DC+AC mode and I supplied about 25Vdc and it hunts. Raised voltage to about 44Vdc and it reads correctly. Lowering the DC voltage and it hunts again.

It looks like all pre-production errors are still present in the first batch of production meters of the 121GW. Even my crappy UNI-T UT71E is doing a better job in all of the discussed bugs.

I like to hear something soon from Dave how they will go on with the production meters of the early adopters...  :-\
Title: Re: EEVBlog 121GW Discussion thread
Post by: ChrisG on January 28, 2018, 11:10:25 pm
I use the AC+DC mode.  On the pre-production meter, this never worked very well.  If you wanted to try something very simple, switch the meter to AC+DC.  Attache the two leads normally (volts and common).   Now attach a DC supply and set it between 5 and 30 volts.  Does the meter just continue to hunt?   If it does, take the supply to 40-50 volts.  Does it now read correctly?    If it does, try lowering the voltage is see if it again starts to hunt.     Surely the released meters AC+DC mode works.

Hi Joe, not sure if what I did was right but I put it in AUTO DC+AC. Connected to my  EEZ H24005 power supply dialed in 25V (2mA current limit) and it displays it at 24.992 volt. on 5V it displays 5.000 volt at 40V it displays 39.989 on the meter. Apart from the still slow update rate it does not hunt in my opinion. Assuming the hunting is going back and forth and not getting a fix?
Title: Re: EEVBlog 121GW Discussion thread
Post by: Candid on January 29, 2018, 03:31:30 am
Are you both using the same firmware? 
I have the 1.02 with the auto range patch installed and I can reproduce the exact same behavior as you showed in the video with the pre-production meter.

I made some quick pictures without tripod. Hope they are ok to see the details:
http://www.abload.de/gallery.php?key=so5gQFPZ (http://www.abload.de/gallery.php?key=so5gQFPZ)
Title: Re: EEVBlog 121GW Discussion thread
Post by: ChrisG on January 29, 2018, 06:21:09 am
Well it was not a cheap power supply at 500€ but will try with a 9V battery then later. I’ve so far not se3n what you show in your viceo. Anyone else?
Title: Re: EEVBlog 121GW Discussion thread
Post by: ChrisG on January 29, 2018, 06:32:36 am
Are you both using the same firmware? 

The pre-production meter would lock in depending on the AC and DC components.  If you have a cheap power supply with a lot of ripple for example, the meter may actually read correctly.   

V1.02 original (no autoranging patch)
Title: Re: EEVBlog 121GW Discussion thread
Post by: prof on January 29, 2018, 07:25:50 am
Just want to add that rotary switch wobble issue exists also with my meter (EU shipped). https://youtu.be/pjaWWMoPMsE
Is this same for everyone or only part of the already shipped meters?

Mine's the same. Not worried about that though.
Title: Re: EEVBlog 121GW Discussion thread
Post by: ez24 on January 29, 2018, 07:40:39 am
Regarding the switch.  It seems like "you can't have your cake and eat it to" issue.

Isn't one of the selling points is that it can be turned with one hand?

My AN8008 switch is tight as it can be but it cannot be turned with one hand unless it is tied down.  Personally I like the one hand use and I am experimenting tying down the AN8008 (zip ties work the best so far).

So far no one has said that if there was no wobble, if it could or not be used with one hand.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Candid on January 29, 2018, 08:08:58 am
First, thank you for taking these pictures!  Don't tell me that's a section of solder stuck to the bottom of the spring??
No it's part of the spring. I already re-soldered it.

Did you notice what appears to be metallic contamination around your pads?  It would be nice to get a better shot of this area with a microscope or macro lens.
Maybe next week or someone else can have a closer look on his meter.

I don't like that you are already seeing what appears metallic dust this early.  Maybe it's something in the lighting.
I did not use any flash, only room light (very strong cold LED at the ceiling and warm LED on the bench) what is not the best for taking neutral pictures. I was surprised myself to see that much dust after only some turns. I may have a second nearer view if I find some time the next days. Hopefully someone else can make some pictures to compare.
Title: Re: EEVBlog 121GW Discussion thread
Post by: KNSSoftware on January 29, 2018, 08:29:26 am

Isn't one of the selling points is that it can be turned with one hand?

So far no one has said that if there was no wobble, if it could or not be used with one hand.

If so, probably only after Dave realised early on that is was never going to be as stiff as the BM235 (which was a selling point about how stiff it was, and any shootout would get extra point for stiffness), and quickly turned a negative into a positive.  I think we underestimate how good he is at the marketing, and his own down playing of this skill, is a key part.  I would bet, if he could have got them to make it as stiff, he would have.
Title: Re: EEVBlog 121GW Discussion thread
Post by: 1anX on January 29, 2018, 08:58:21 am
Just tested it. AUTO DC+AC mode and I supplied about 25Vdc and it hunts. Raised voltage to about 44Vdc and it reads correctly. Lowering the DC voltage and it hunts again.

It looks like all pre-production errors are still present in the first batch of production meters of the 121GW. Even my crappy UNI-T UT71E is doing a better job in all of the discussed bugs.

I like to hear something soon from Dave how they will go on with the production meters of the early adopters...  :-\

A fair and candid, (pun intended) comment !

I cant see us hearing from Dave anytime soon as he is keeping a very low profile and with good reason. He cant comment until he has a defined course of action to rectify the bugs and switch issue. Its up to UEi at this stage to pull their finger out and and turn this first "production" run meter into what it should be.

Dave needs to be extremely diplomatic with both his backers/buyers and with UEi. Nothing to be gained by pounding a fist on a table! As much as I dislike the situation with this meter, I am following Dave's lead with patience and high expectations for speedy fix.

The meter's potential with its unique specification is high and so is its potential for high worldwide sales. It will be interesting to see if Dave can turn the V1.0 bugs around and turn it into a best seller. It will also be interesting to see if UEi has the technology and ability to respond quickly to this meter's faults and apply thorough testing before releasing V1.01.

The EEVBlog forum has proved its worth once again by providing insights into this meter's teething problems and also presenting some impressive solutions. The firmware hacking and Joe's testing of the prototype, and informing us all of the carryover bugs, stand out for me!
Title: Re: EEVBlog 121GW Discussion thread
Post by: tpw_rules on January 29, 2018, 09:14:52 am
Are you both using the same firmware? 

The pre-production meter would lock in depending on the AC and DC components.  If you have a cheap power supply with a lot of ripple for example, the meter may actually read correctly.   

V1.02 original (no autoranging patch)
Strange.  You would think it would do it or it wouldn't.  I am not sure what sort of regression testing is being ran on the patched code.  Maybe the patch has something to do with it.   

Yeah, it was a regression.

The original problem was that AC/DC mode operates by switching the meter mode every measurement and caching the result, to mix in when measuring the other mode. So you'd get:
1. read 5.5000V DC, store as 55000 counts. Autorange decides to range up.
2. switch to reading AC, read 00.000V, add previous DC counts to show 55.000V. Autorange decides to range up.
3. switch to reading DC, read 005.50V, add previous AC counts to show 005.50V. Autorange decides to range down.
4. switch to reading AC, read 00.000V, add previous DC counts to show 00.550V. Autorange decides to range down.
5. and so on and so on, literally forever.

The obvious way to bring the meter back is to input a DC value that's > 4000 and < 55000 counts, which explains in Joe's video why it hunts starting around 5.0000V and comes back at nearly exactly 40.00V. Or, input an AC value that results in a value within that range after both a bogus addition and a correct addition (by the way, it's not addition, it's sqrt(AC^2+DC^2) which I don't entirely understand why), so autorange settles down. So yeah, it definitely can depend on the AC and DC content.

Anyway, they fixed this by adding a delay so it would show two measurements before autorange decided to act again, thus flushing the bogus cached counts. But my patch mashes that delay to 0 whenever autorange acts (vs. the user), giving the same situation. My apologies for the confusion, but I can't test anything due to the delay in the US meters. I'll look into either applying that only to the resistance range, or perhaps just not to AC+DC mode.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on January 29, 2018, 09:43:34 am

Isn't one of the selling points is that it can be turned with one hand?

So far no one has said that if there was no wobble, if it could or not be used with one hand.

If so, probably only after Dave realised early on that is was never going to be as stiff as the BM235 (which was a selling point about how stiff it was, and any shootout would get extra point for stiffness), and quickly turned a negative into a positive.  I think we underestimate how good he is at the marketing, and his own down playing of this skill, is a key part.  I would bet, if he could have got them to make it as stiff, he would have.

Actually, I think the BM235 range switch is a bit too stiff, I find i have to apply some downward pressure in order to switch it one handed on a smooth surface, worse if it's up on the tilt stand
Whilst the 121GW technically has the same pressure issue, the action is less "violent" than the BM235 and requires less force. Sometimes I think that's better, sometimes not, depending upon my mood and usage scenario, it's entirely personal preference. The 121GW range switch was simply UEi's standard method used in their other meters and I didn't see any reason to mess with it.
Title: Re: EEVBlog 121GW Discussion thread
Post by: nuclearcat on January 29, 2018, 10:09:23 am
A bit fun with 121GW bluetooth data stream + USB microscope + (C++/wxwidgets/OpenCV to add OSD layer)
https://www.youtube.com/watch?v=nIbdnlQJ1fA&feature=youtu.be (https://www.youtube.com/watch?v=nIbdnlQJ1fA&feature=youtu.be)
Still PoC, not sure if such will be useful, or maybe such apps already exist.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Seppy on January 29, 2018, 04:08:11 pm
I am having problems with connecting the 121GW app from dave2. I did no get any data shown in the app up to now. Most time it even does not connect.

I first run bluetooth and connect to the 121GW then I start the app. Sometimes when I click on refresh I can see the 121GW. Only one time it was able to connect (but no data shown, only white screen). Most time it says "connecting..." but never does.

The other app "EEVBlog 121GW" sometimes connects successfully and shows some values but sorry, it's so ugly.

/EDIT:
Now I got it running for one time but I think I am missing some data on the screen?

There are a couple things to note when using the app and its easy to prevent it from working.
1. Make sure only one instance is running at a time.
2. You shouldn't need to pair the app at all on android to give that a try before you go and pair the device.

It seems people tend to open the app to see what they installed then pair or enable bluetooth, then open a second instance of the app. That is known to cause issues.
Title: Re: EEVBlog 121GW Discussion thread
Post by: ChrisG on January 30, 2018, 04:49:35 am
Hi Joe, I just tried it and can not replay your issue in the video. 10Vpp sine-wave from the Siglent SDG 2042X into the 121GW and the BM869s connected too. This 121GW on any ms range indicates correctly at frequencies from 10Hz to 200Hz (10, 50, 100, 200). I can not get a wrong reading on the meter. Still on V1.02 not patched for slow update rate.
Title: Re: EEVBlog 121GW Discussion thread
Post by: ChrisG on January 30, 2018, 04:55:20 am
Well it was not a cheap power supply at 500€ but will try with a 9V battery then later. I’ve so far not se3n what you show in your viceo. Anyone else?

Hi Joe, tried a 9v (actually bit dated and went to 8v) battery. Apart from slow auto-ranging no issue on locking in. So if slow auto-ranging is hunting then yes but I assume not.
Title: Re: EEVBlog 121GW Discussion thread
Post by: benst on January 30, 2018, 10:39:29 am
Just want to add that rotary switch wobble issue exists also with my meter (EU shipped). https://youtu.be/pjaWWMoPMsE
Is this same for everyone or only part of the already shipped meters?
Mine (#000499) is similar, maybe a bit less.

Edit: and I have the funky display sometimes. Wiggling the switch a few times fixes it.

Ben
Title: Re: EEVBlog 121GW Discussion thread
Post by: dcac on January 30, 2018, 12:43:18 pm
Yet another auto ranging benchmark - Keysight U1461A which also uses hy3131 but has a 6600 counts mode - goes from infidelity infinity to zero ohms in just 2.2-2.4 sec. Though it only goes down to 0.1 ohms resolution so to be fair 121gw has two more range steps to complete. Still seems promising if a low resolution mode can be added to 121gw.

Perhaps sniffing the bus on how U1461A controls the hy3131 could give an idea how it achieves this speed. But if we're unlucky there are other HW differences that makes the 121gw so dreadfully slow.

Title: Re: EEVBlog 121GW Discussion thread
Post by: ANTALIFE on January 30, 2018, 10:56:56 pm
Quick question/problem, I am trying to measure power (VA) of a device plugged into an AUS AC socket.
I have everything connected as per diagram on pg46 of manual (11 December 2017 rev), when I switch to mVA/VA mode (in AC too) I get Vac too large to read.
Interestingly enough I can measure Vac & Iac individually which come out as ~245Vrms & ~16mA (rms?)

So my question is, am I doing something wrong or is the meter not designed to measure stuff plugged into an AC socket
Title: Re: EEVBlog 121GW Discussion thread
Post by: ChrisG on January 30, 2018, 11:06:55 pm
Hi Joe, I just tried it and can not replay your issue in the video. 10Vpp sine-wave from the Siglent SDG 2042X into the 121GW and the BM869s connected too. This 121GW on any ms range indicates correctly at frequencies from 10Hz to 200Hz (10, 50, 100, 200). I can not get a wrong reading on the meter. Still on V1.02 not patched for slow update rate.
Well it was not a cheap power supply at 500€ but will try with a 9V battery then later. I’ve so far not se3n what you show in your viceo. Anyone else?

Hi Joe, tried a 9v (actually bit dated and went to 8v) battery. Apart from slow auto-ranging no issue on locking in. So if slow auto-ranging is hunting then yes but I assume not.
9V I assume was for the AC+DC mode.  If you read the previous posts, looks like the reason for the difference was indeed the patch.   It appears they did address a few of the problems.   I think the big one is what appears to be a metallic dust in those previous pictures.  If you have been putting a few cycles on yours (even a few hundred total) and a camera that you can take some close ups of the pad area, it would be interesting to see a few more pictures.   

Hi Joe, I'll give that a go the coming days. Too much normal work going on for me at the moment. I'm not sure I'm looking forward to this to be honest. If the tracks are or seem to deteriorate quickly I would be appalled. Are you getting an official, non pre-production, 121GW soon perhaps?
Title: Re: EEVBlog 121GW Discussion thread
Post by: ChrisG on January 30, 2018, 11:54:11 pm
Hi Joe, I just tried it and can not replay your issue in the video. 10Vpp sine-wave from the Siglent SDG 2042X into the 121GW and the BM869s connected too. This 121GW on any ms range indicates correctly at frequencies from 10Hz to 200Hz (10, 50, 100, 200). I can not get a wrong reading on the meter. Still on V1.02 not patched for slow update rate.
Well it was not a cheap power supply at 500€ but will try with a 9V battery then later. I’ve so far not se3n what you show in your viceo. Anyone else?

Hi Joe, tried a 9v (actually bit dated and went to 8v) battery. Apart from slow auto-ranging no issue on locking in. So if slow auto-ranging is hunting then yes but I assume not.
9V I assume was for the AC+DC mode.  If you read the previous posts, looks like the reason for the difference was indeed the patch.   It appears they did address a few of the problems.   I think the big one is what appears to be a metallic dust in those previous pictures.  If you have been putting a few cycles on yours (even a few hundred total) and a camera that you can take some close ups of the pad area, it would be interesting to see a few more pictures.   

Hi Joe, I'll give that a go the coming days. Too much normal work going on for me at the moment. I'm not sure I'm looking forward to this to be honest. If the tracks are or seem to deteriorate quickly I would be appalled. Are you getting an official, non pre-production, 121GW soon perhaps?
Personally, I would rather know if there was a problem early on.   If there is, maybe it could be corrected before any major damage happens to the PCB.  What sort of warranty did you get?   If you put a few thousand cycles on the switch over the next few weeks and the parts are damaged, is the meter covered? 

From what I understand, very few meters made it to people in the USA so even if I had joined, I doubt I would have it.  Strange as I would have thought they would have been the largest consumer.   Anyway, I was concerned that there had not been a full review of the meter that disclosed what the problems were and how they would be mitigated.  Obviously, there were problems that have been known for some time.  I had asked a question in the kickstarter that went unanswered.   Also, looking at the closeup video, it appeared the meter's weak front end was still in play.  Again, it's not a lot of money but if I bought one it would be to run it to failure and I did not want to invest this amount of time if the design was still not stable or if it was not going to be an improvement over the earlier version.  If and when it looks like the meter is stable and it becomes available through normal channels, I may run one.   For now, it seems it is way too early.   

Agree with you Joe and at the same time I'm happy I did join the campaign very much so. It's a joint effort in the end of this community to come up with a solid product and I would not have expected it to be perfect during the first production version. However traces on the PCB which are not up to spec would a, as said already, disappoint me.
BTW: I thought the front end was pretty okay and not weak. Did I miss it in your pre-production test video?
Title: Re: EEVBlog 121GW Discussion thread
Post by: Smokey on January 31, 2018, 09:54:31 am
....Keysight U1461A .... goes from infidelity to zero ohms in just 2.2-2.4 sec

HA!  I thought infidelity was already due to low resistance
Title: Re: EEVBlog 121GW Discussion thread
Post by: dcac on January 31, 2018, 11:04:24 am
....Keysight U1461A .... goes from infidelity to zero ohms in just 2.2-2.4 sec

HA!  I thought infidelity was already due to low resistance

lol, yeah autocomplete at its best - should of course have been - infinity to zero ohms in 2.2-2.4 sec.

Title: Re: EEVBlog 121GW Discussion thread
Post by: dcac on January 31, 2018, 11:27:28 am
From what I understand, very few meters made it to people in the USA so even if I had joined, I doubt I would have it.  Strange as I would have thought they would have been the largest consumer.

Probably the large time difference between USA and Australia caused potential consumers to be too late in the game - at least for the first batch anyway.

Title: Re: EEVBlog 121GW Discussion thread
Post by: nidlaX on January 31, 2018, 02:13:54 pm
From what I understand, very few meters made it to people in the USA so even if I had joined, I doubt I would have it.  Strange as I would have thought they would have been the largest consumer.

Probably the large time difference between USA and Australia caused potential consumers to be too late in the game - at least for the first batch anyway.
No... The US meters were simply stuck in customs all the way up to when the switch tolerance issue was reported. Now they won't ship until that issue is fixed.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on January 31, 2018, 04:51:28 pm
Look at the data.  There are several meters that have done very well in these tests.  2KV is lower than the average and not something I would be impressed with.  I was just as surprised by the Fluke 87V result.  Received a lot of negative posts over that one from the fans.  Not much I can say about how the meter's do in the tests.   I can say that the Fluke 87V is not what I consider the goal post.

I guess this goes to show how important this stuff actually is in the real world, as much as we all like to fuss over these sorts of details because, you know, we are nerds.
I have never heard a single person complain that the Fluke 87 series isn't a robust industrial meter, and not surprising because it's been an industry standard for like 30 years now.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on January 31, 2018, 04:53:49 pm
Perhaps sniffing the bus on how U1461A controls the hy3131 could give an idea how it achieves this speed. But if we're unlucky there are other HW differences that makes the 121gw so dreadfully slow.

FYI, the 121GW is now on par with the U1282A.
Title: Re: EEVBlog 121GW Discussion thread
Post by: 1anX on January 31, 2018, 05:08:29 pm
Perhaps sniffing the bus on how U1461A controls the hy3131 could give an idea how it achieves this speed. But if we're unlucky there are other HW differences that makes the 121gw so dreadfully slow.

FYI, the 121GW is now on par with the U1282A.

So whats that in Seconds?
How are UEi progressing on the bug fixes?
Any timeline on when they expect to have a fully functional and thoroughly tested meter to ship?
Sounds like progress is being made, so thats good news  :-+
Title: Re: EEVBlog 121GW Discussion thread
Post by: exe on January 31, 2018, 11:32:01 pm
Dave, a week or two ago you mentioned Dave2 was working on making some instructions how to make own firmware for the meter (or was it only about how to flash it?). Is there any progress on this? I understand you are busy guys, but I'd appreciate any information on how to roll own firmware so I could start developing it (or other duded smarted than me). I know it's possible to reverse-engineer the current firmware, but I think it's a waste of time this is inefficient. Also, I think it is already proven community can fix problems much faster than any manufacturer.

I also would like to get more updates on the meter. Any rumors, estimations, etc. So, we could see it's not abandoned. If possible. Or, better, a UEI representative here in the thread. Like other manufacturers do on this forum (e.g., MicSig, R&S, Siglent (tautech), Rigol, etc).
Title: Re: EEVBlog 121GW Discussion thread
Post by: joeqsmith on January 31, 2018, 11:35:34 pm
Look at the data.  There are several meters that have done very well in these tests.  2KV is lower than the average and not something I would be impressed with.  I was just as surprised by the Fluke 87V result.  Received a lot of negative posts over that one from the fans.  Not much I can say about how the meter's do in the tests.   I can say that the Fluke 87V is not what I consider the goal post.

I guess this goes to show how important this stuff actually is in the real world, as much as we all like to fuss over these sorts of details because, you know, we are nerds.
I have never heard a single person complain that the Fluke 87 series isn't a robust industrial meter, and not surprising because it's been an industry standard for like 30 years now.
As I have mentioned before, I  really don't know what the failure rate is for the 87V.  I've seen posts where they have failed which is not too surprising.  Enough hype and marketing can easily cover up any short comings.   You are right that there are people that that care less about the marketing and more about the results.  I certainly classify myself in that category and offer these test results as proof of that. 

Another data point we have is the age of the 87V and how it compares with Fluke's newer designs.  I've also looked at the 101,107,115 and 17B+.  All newer, all from China.   The worst of them was the Fluke 17B+ that was damaged at 10KV 50us.   Sure, it could be by accident that their newer meters are so much more robust but I doubt it.  I suspect it has more to do with reducing the number of field failures and warranty returns.  But again, I really don't know and can only present the data.   It's up to the people that view it to interpret it.     
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on February 01, 2018, 12:20:00 am
Look at the data.  There are several meters that have done very well in these tests.  2KV is lower than the average and not something I would be impressed with.  I was just as surprised by the Fluke 87V result.  Received a lot of negative posts over that one from the fans.  Not much I can say about how the meter's do in the tests.   I can say that the Fluke 87V is not what I consider the goal post.

I guess this goes to show how important this stuff actually is in the real world, as much as we all like to fuss over these sorts of details because, you know, we are nerds.
I have never heard a single person complain that the Fluke 87 series isn't a robust industrial meter, and not surprising because it's been an industry standard for like 30 years now.
As I have mentioned before, I  really don't know what the failure rate is for the 87V.  I've seen posts where they have failed which is not too surprising.  Enough hype and marketing can easily cover up any short comings.

Or maybe the "short comings" aren't really short comings in a practical world? And the 87V's reputation as one of the most reliable and robust meters on the market is actually well earned?
Maybe the 61010 CAT IV 600V rating as tested by UL is more than enough for almost everyone?
For instance, the now infamous 87V GSM bug wasn't found for a decade, and countless units sold of the biggest selling meter on the market.
Or the very popular Keysight U1272A's EMC problem taking how long before someone found it?

Title: Re: EEVBlog 121GW Discussion thread
Post by: dcac on February 01, 2018, 03:11:58 am
Perhaps sniffing the bus on how U1461A controls the hy3131 could give an idea how it achieves this speed. But if we're unlucky there are other HW differences that makes the 121gw so dreadfully slow.

FYI, the 121GW is now on par with the U1282A.

FYI, that still makes it dreadfully slow - I’m sorry, but I guess I miss the old clonk-clonk-clonk Dave who’d facepalme and hammer his failbutton through the desk if confronted with an auto-ranging this slow on a DMM in this class. But still I really do appreciate what you’re trying to provide with the 121gw and my main point was that the U1461 was so much faster in a 6000 count mode.

Am I expecting UEi to provide a fast 5000 count mode for 121gw? - no not really - but they’re in a much better position having the FW source code to make an addition like that - compared to hacking/patching the binaries. But I’m starting to wonder if UEi them self is limited in what they can achieve with the development tools they’re using. Else I can’t really understand why 121gw ever was released with an auto-raging that was so slow that backers would go seriously WTF!
Title: Re: EEVBlog 121GW Discussion thread
Post by: ChrisG on February 01, 2018, 03:26:45 am
Perhaps sniffing the bus on how U1461A controls the hy3131 could give an idea how it achieves this speed. But if we're unlucky there are other HW differences that makes the 121gw so dreadfully slow.

FYI, the 121GW is now on par with the U1282A.

FYI, that still makes it dreadfully slow - I’m sorry, but I guess I miss the old clonk-clonk-clonk Dave who’d facepalme and hammer his failbutton through the desk if confronted with an auto-ranging this slow on a DMM in this class. But still I really do appreciate what you’re trying to provide with the 121gw and my main point was that the U1461 was so much faster in a 6000 count mode.

Am I expecting UEi to provide a fast 5000 count mode for 121gw? - no not really - but they’re in a much better position having the FW source code to make an addition like that - compared to hacking/patching the binaries. But I’m starting to wonder if UEi them self is limited in what they can achieve with the development tools they’re using. Else I can’t really understand why 121gw ever was released with an auto-raging that was so slow that backers would go seriously WTF!


That would not be good at all and with all the issues piling up till now and the fact that some if not most are really HW related it starts to be a real problem for me. This morning I had to cycle the knob 3-4 times before it wanted to switch on?   :-//  how can that be?
Title: Re: EEVBlog 121GW Discussion thread
Post by: ChrisG on February 01, 2018, 04:38:53 am
POSTING again since the other one got lost?

Herewith the pictures of the PCB selector tracks.
Title: Re: EEVBlog 121GW Discussion thread
Post by: ChrisG on February 01, 2018, 04:42:23 am
Another set.
Title: Re: EEVBlog 121GW Discussion thread
Post by: ChrisG on February 01, 2018, 04:47:45 am
3rd set. Comments to follow.
Title: Re: EEVBlog 121GW Discussion thread
Post by: The Soulman on February 01, 2018, 04:59:53 am
ChrisG, can you post pictures of the wiper contacts as well? Just curious.
Title: Re: EEVBlog 121GW Discussion thread
Post by: ChrisG on February 01, 2018, 05:22:01 am
They are spotless.  And I just put the whole thing together again... :-)
Title: Re: EEVBlog 121GW Discussion thread
Post by: ChrisG on February 01, 2018, 05:38:15 am
Appears to have less contamination but we have no idea how many cycles were on the two meters posted so far.   Can you tell with your eyes if any of that is metallic?   

I wonder how the people with the intermittent switches would compare with the ones the work as expected.  It would seem that the intermittent meters make have less contact force and would be less prone to wear but we really don't know.   

Does not seem to be metallic but I'm not an expert. On purpose I did not clean the contacts though. Btw I just noticed that on the wiper side there also one track very close to the hole of the selector pivot. As already said the wiper dots where pretty clean and shiny. Let's keep this conversation going please. Perhaps other people dare to open up their 121GW and see, check or take pictures. BTW Dave and Dave could also open up their 121GW's right?
Title: Re: EEVBlog 121GW Discussion thread
Post by: Candid on February 01, 2018, 05:43:14 am
Appears to have less contamination but we have no idea how many cycles were on the two meters posted so far.   Can you tell with your eyes if any of that is metallic?
I posted the first pictures and checked today. I think it's not metallic at least not magnetic. I checked with a strong neodyn magnet and it doesn't feel metallic.

I cleaned it and will check in some weeks.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on February 01, 2018, 09:10:40 am
Practical world sounds like a marketing term.  I really have no idea idea about the 87Vs reputation, if it has one or how it came to be.

After almost 30 years in the industry I can assure you it has that reputation. But I guess you have to be in the industry and closely follow this stuff to know.
How did it get that rep? - With a great deal of time giving dependable and trustworthy service.
But this is a 121GW thread so I'll stop talking about this now.
Title: Re: EEVBlog 121GW Discussion thread
Post by: 1anX on February 01, 2018, 09:18:55 am
I also would like to get more updates on the meter. Any rumors, estimations, etc. So, we could see it's not abandoned. If possible. Or, better, a UEI representative here in the thread. Like other manufacturers do on this forum (e.g., MicSig, R&S, Siglent (tautech), Rigol, etc).

Dave, I think it is time that you found your voice and provide an update of the current situation!

What progress, (if any) has been made by you and UEi in rectifying the faults?

I am becoming concerned by the lack of communication and wondering if the root cause of the "bugs" is hardware related and only you can provide details on the meter to make clear the situation.

Considerable time has passed without you providing meaningful info on the rectification of the meter's abundant faults.

The meter comes with a warranty and is covered under ACCC laws, but I'm hoping you will be proposing a meter replacement/fix program for the shipped meters and a thorough revision for the meters awaiting manufacture/shipping.

With great respect, what is the current state of play Dave?
Title: Re: EEVBlog 121GW Discussion thread
Post by: amspire on February 01, 2018, 10:01:41 am
I also would like to get more updates on the meter. Any rumors, estimations, etc. So, we could see it's not abandoned. If possible. Or, better, a UEI representative here in the thread. Like other manufacturers do on this forum (e.g., MicSig, R&S, Siglent (tautech), Rigol, etc).

Dave, I think it is time that you found your voice and provide an update of the current situation!

What progress, (if any) has been made by you and UEi in rectifying the faults?

I am becoming concerned by the lack of communication and wondering if the root cause of the "bugs" is hardware related and only you can provide details on the meter to make clear the situation.

Considerable time has passed without you providing meaningful info on the rectification of the meter's abundant faults.

The meter comes with a warranty and is covered under ACCC laws, but I'm hoping you will be proposing a meter replacement/fix program for the shipped meters and a thorough revision for the meters awaiting manufacture/shipping.

With great respect, what is the current state of play Dave?
IanX,

If you have a meter that is so faulty that you are talking about invoking ACCC laws, then I hope you have contacted Dave directly - as the ACCC would expect you to do first.

Dave has actually given a lot of communication - far more then any other manufacturer I have seen and he does not even design or make the meters. Just be patient.

I am puzzled by your mention of the "abundant faults". My meter is pretty functional. The biggest issue that people seem to raise is the slow autoranging that is not a fault, but it is being improved.

I am prepared to wait for issues and improvements to be fully tested before release. I have a 121GW meter that seems to be safe and measures volts, amps, resistance, temperature, capacitance, frequency and duty factor all within specifications. I am very happy that Dave has already seen updates that will improve the meter.

What sort of meter did you get?
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on February 01, 2018, 10:20:47 am
I also would like to get more updates on the meter. Any rumors, estimations, etc. So, we could see it's not abandoned. If possible. Or, better, a UEI representative here in the thread. Like other manufacturers do on this forum (e.g., MicSig, R&S, Siglent (tautech), Rigol, etc).

Dave, I think it is time that you found your voice and provide an update of the current situation!
What progress, (if any) has been made by you and UEi in rectifying the faults?

The issues are being investigated, stuff just takes time, especially when you have more than one issue. There is no point in me speculating daily.
There is essentially very little I can do personally to speed this up or really even help them out from a technical perspective.
They are still waiting on the range switch parts, due in a few days I believe, and then there is testing etc.
On top of that of course are several software issues, some like slow autoranging for example has been solved (to match that of the U1282A), others are still being worked on (presumably one by one).
Please be patient, when I know for certain, you'll know.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on February 01, 2018, 10:39:11 am
1anX - you seem to be running hot and cold....

I cant see us hearing from Dave anytime soon as he is keeping a very low profile and with good reason. He cant comment until he has a defined course of action to rectify the bugs and switch issue. Its up to UEi at this stage to pull their finger out and and turn this first "production" run meter into what it should be.

Dave needs to be extremely diplomatic with both his backers/buyers and with UEi. Nothing to be gained by pounding a fist on a table! As much as I dislike the situation with this meter, I am following Dave's lead with patience and high expectations for speedy fix.

and now this...

Dave, I think it is time that you found your voice and provide an update of the current situation!

What progress, (if any) has been made by you and UEi in rectifying the faults?

I am becoming concerned by the lack of communication and wondering if the root cause of the "bugs" is hardware related and only you can provide details on the meter to make clear the situation.

Considerable time has passed without you providing meaningful info on the rectification of the meter's abundant faults.

The meter comes with a warranty and is covered under ACCC laws, but I'm hoping you will be proposing a meter replacement/fix program for the shipped meters and a thorough revision for the meters awaiting manufacture/shipping.

With great respect, what is the current state of play Dave?

My definition of "patience" in this scenario is a little more than a couple of days.  It's taken over 2 years of development to get the 121GW to where it is today - and the first run of units were bound to encounter some issues when released to the sort of people who frequent here.

In my limited experience, Dave has been pretty candid with his comments - and usually only says something when there is something worth saying.  If you want comforting on a daily basis, then that's not going to happen here.

This stuff takes time.

Oh, and even mentioning the ACCC at this point is really unfair.  Not only that - but it comes across as a threat.

Besides, the ACCC won't give a flying fig about getting the meter fixed to your satisfaction.  They would look at these threads and immediately understand what the situation is and they will tell you to talk to Dave.  They will simply ensure that you haven't been swindled.  An issue which would be immediately resolved by returning the meter and getting a full refund.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on February 01, 2018, 10:42:23 am
My post above was written as Dave made his reply - but I posted it on principle.

I also would like to get more updates on the meter. Any rumors, estimations, etc. So, we could see it's not abandoned. If possible. Or, better, a UEI representative here in the thread. Like other manufacturers do on this forum (e.g., MicSig, R&S, Siglent (tautech), Rigol, etc).

Dave, I think it is time that you found your voice and provide an update of the current situation!
What progress, (if any) has been made by you and UEi in rectifying the faults?

The issues are being investigated, stuff just takes time, especially when you have more than one issue. There is no point in me speculating daily.
There is essentially very little I can do personally to speed this up or really even help them out from a technical perspective.
They are still waiting on the range switch parts, due in a few days I believe, and then there is testing etc.
On top of that of course are several software issues, some like slow autoranging for example has been solved (to match that of the U1282A), others are still being worked on (presumably one by one).
Please be patient, when I know for certain, you'll know.

This shows exactly what I expected.

... and you can't say he isn't responsive!!
Title: Re: EEVBlog 121GW Discussion thread
Post by: rstofer on February 01, 2018, 12:27:41 pm
This certainly won't be my first or only meter.  Whether I get it today, next month or even a few months from now really makes no difference.  Sure, I'm looking forward to receiving it because, among other things, it is already paid for.  But I would rather have the upgraded switch and firmware rather than try to figure out what to do next. It takes what it takes and getting these issues resolved before it ships to me makes all the sense in the world (to me).

Title: Re: EEVBlog 121GW Discussion thread
Post by: lowimpedance on February 01, 2018, 01:24:33 pm
About a week ago I reported the mechanical issue I had on my 121 with the switch and input terminals here ;
https://www.eevblog.com/forum/testgear/eevblog-121gw-multimeter-issues/msg1403241/#msg1403241 (https://www.eevblog.com/forum/testgear/eevblog-121gw-multimeter-issues/msg1403241/#msg1403241)

So after returning from holiday I thought I would have a look inside at what may be happening with my meter.
What I can see happening with mine to cause my issue was the small flexing of the PCB by the input plugs movement
was causing referred movement at the switch area and since my switch was rather 'sloppy' in its location hole this had caused
either contact or contact location issues on their relevant PCB tracks and thus the mode failures.

Further investigation of the switch rotor showed quite a lot of lateral movement in the PCB locating hole.
So next step was what to do to reduce this lateral 'slop'!.
After removing the PCB from the switch knob I could test fit various rod diameters, (rear ends of twist drills in 0.1mm inc.), to lightly expand
the switch plate plastic fingers that go through the main PCB to remove the slop but still have easy rotational movement.
The best size for my meter was 6.1mm OD. To help alignment further I made the ID be a good sliding fit to the hex shaft of the knob at 5.6mm.
 The resulting sleeve I machined up can be seen in the photo below in its final position (I left it longer so its easily removed.). The material used was PEEK which is
reasonably stiff and has good insulation properties, (I also had it anyway  :P). Did not want to use PTFE which would have been too soft at the cross section used.

As an additional exercise I also cut up some 0.3mm PTFE sheet as spacers under the knob circlip, see photo below. Two pieces provided a good take up
of the space between the housing and the circlip. This reduced the knob free play up and down but allowed some compliance in the well in the top housing and the circlip too
due to the soft flexible nature of the PTFE.

So the end result of this exercise was a considerably less 'wobbly' feel to the knob and more importantly all the issues I had reported have now gone
completely and any movement of the input plugs have no effect on the switch nor does wiggling the knob itself set off any failures of the mode its in.
Title: Re: EEVBlog 121GW Discussion thread
Post by: 1anX on February 01, 2018, 03:33:31 pm
This certainly won't be my first or only meter.  Whether I get it today, next month or even a few months from now really makes no difference.  Sure, I'm looking forward to receiving it because, among other things, it is already paid for.  But I would rather have the upgraded switch and firmware rather than try to figure out what to do next. It takes what it takes and getting these issues resolved before it ships to me makes all the sense in the world (to me).

Agreed!

I have a collection of meters and was going to by a second Fluke, but then Dave came along with his integration of a few good ideas to make a "unique" meter. I put the Fluke on hold as I watched his ideas develop into a best bang for buck meter. Hackable and with BLE and the low burden voltage won me over, as I was seriously considering a uCurrentGold.

So Dave has my money and I'm looking forward to a best bang for buck meter turning up in March or whenever. I'm concerned that UEi have stumbled at the first production run and the switch is an issue. Look forward to seeing if Dave's good ideas get the build quality they deserve!
Title: Re: EEVBlog 121GW Discussion thread
Post by: 1anX on February 01, 2018, 03:38:10 pm
I'm hoping to use this meter for measuring ucurrent on my ESP32 projects. Has anyone used the meter for ucurrent measurement by placing a zero ohm shunt in place of the fuses? If you have tried it what burden voltage was present and how does it compare to the uCurrentGold?
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on February 01, 2018, 04:11:57 pm
I'm hoping to use this meter for measuring ucurrent on my ESP32 projects. Has anyone used the meter for ucurrent measurement by placing a zero ohm shunt in place of the fuses? If you have tried it what burden voltage was present and how does it compare to the uCurrentGold?

You can calculate that from the schematic value for the shunt resistors.
http://www.eevblog.com/files/121GW%20EEVBlog%20Circuit%20diagram.pdf (http://www.eevblog.com/files/121GW%20EEVBlog%20Circuit%20diagram.pdf)
10mohm, 1.01ohm, and 100.1ohms.
x1 or x10 amp depending on range using that shunt.
Title: Re: EEVBlog 121GW Discussion thread
Post by: JonM on February 01, 2018, 04:31:01 pm
For anyone interested in Dave candidly discussing the 121GW issues:

 https://theamphour.com/377-debugger-vs-printeffer/

Spoilers: Dave chuckles over the irony of the slow resistance settling time and what he has said about other meters.  He also noted that the slowness was introduced in a late firmware update and he noted that they should have had a formal list of tests to be done for each release.

I'm standing by for the US deliveries....
Title: Re: EEVBlog 121GW Discussion thread
Post by: lowimpedance on February 01, 2018, 04:34:20 pm
About a week ago I reported the mechanical issue I had on my 121 with the switch and input terminals here ;
https://www.eevblog.com/forum/testgear/eevblog-121gw-multimeter-issues/msg1403241/#msg1403241 (https://www.eevblog.com/forum/testgear/eevblog-121gw-multimeter-issues/msg1403241/#msg1403241)
....
The best size for my meter was 6.1mm OD. To help alignment further I made the ID be a good sliding fit to the hex shaft of the knob at 5.6mm.
 The resulting sleeve I machined up can be seen in the photo below in its final position (I left it longer so its easily removed.). The material used was PEEK which is
reasonably stiff and has good insulation properties, (I also had it anyway  :P). Did not want to use PTFE which would have been too soft at the cross section used.
....
So the end result of this exercise was a considerably less 'wobbly' feel to the knob and more importantly all the issues I had reported have now gone
completely and any movement of the input plugs have no effect on the switch nor does wiggling the knob itself set off any failures of the mode its in.

By adding the sleeve, I wonder if the PCB will wear away at shaft where it rotates in the hole.  Time will tell.
I did apply a small amount of contact type grease in that area but I also made sure the pressure from the sleeve was just enough to mitigate the lateral movement without grossly effecting the rotary movement of the switch.
Title: Re: EEVBlog 121GW Discussion thread
Post by: JonM on February 01, 2018, 04:34:31 pm
I forgot to mention that a couple of days ago I dumped the batteries out of a set top box remote control I need to return and was surprised to see that they were made by UEI. I wonder if the 121GW comes with a UEI battery?

Title: Re: EEVBlog 121GW Discussion thread
Post by: lowimpedance on February 01, 2018, 04:39:30 pm
I forgot to mention that a couple of days ago I dumped the batteries out of a set top box remote control I need to return and was surprised to see that they were made by UEI. I wonder if the 121GW comes with a UEI battery?
For us in Oz it was duracell.
Title: Re: EEVBlog 121GW Discussion thread
Post by: amspire on February 01, 2018, 04:57:45 pm

So after returning from holiday I thought I would have a look inside at what may be happening with my meter.
What I can see happening with mine to cause my issue was the small flexing of the PCB by the input plugs movement
was causing referred movement at the switch area and since my switch was rather 'sloppy' in its location hole this had caused
either contact or contact location issues on their relevant PCB tracks and thus the mode failures.

Further investigation of the switch rotor showed quite a lot of lateral movement in the PCB locating hole.
So next step was what to do to reduce this lateral 'slop'!.
After removing the PCB from the switch knob I could test fit various rod diameters, (rear ends of twist drills in 0.1mm inc.), to lightly expand
the switch plate plastic fingers that go through the main PCB to remove the slop but still have easy rotational movement.
The best size for my meter was 6.1mm OD. To help alignment further I made the ID be a good sliding fit to the hex shaft of the knob at 5.6mm.
 The resulting sleeve I machined up can be seen in the photo below in its final position (I left it longer so its easily removed.). The material used was PEEK which is
reasonably stiff and has good insulation properties, (I also had it anyway  :P). Did not want to use PTFE which would have been too soft at the cross section used.

As an additional exercise I also cut up some 0.3mm PTFE sheet as spacers under the knob circlip, see photo below. Two pieces provided a good take up
of the space between the housing and the circlip. This reduced the knob free play up and down but allowed some compliance in the well in the top housing and the circlip too
due to the soft flexible nature of the PTFE.

In the following, when I refer to just the "switch", I meant all the parts attached to the circuit board.

I decided to fix my 121GW wobbly switch up a while ago, but after looking at the mechanism, I took a very different approach. I did look at your method but I think it was making the situation even worse rather then better mechanically.

First, instead of putting a spacer under the circlip, I put a spacer between the knob and the the nylon detent spring so that the circlip was in contact with the case plastic. This lifts the knob upwards. I didn't make it tight. I just wanted to stop any signifigant vertical movement. The reason for this method was so that the circlip does not press on the switch at all. If you put spacers under the circlip, the circlip is pressing on the switch which I think is wrong. The spacer was actually just many layers of duct tape. I had a punch to make a nice hole in the middle.

But now the knob was even looser. So I added a few strips of Kapton tape around the knob sides to widen it till it stopped wobbling much. You want to change a cone shape that is narrowest at the top to one widest at the top, so start off with a thin strip of tape just near the top side of the knob . Then a thicker one that goes to 2/3 down the knob  sides. Then some that goes around the whole sides. The idea is to increase the knob diameter to the point it can hardly wobble, but still have a tiny clearance to the case. Correctly done and the knob is no stiffer then before.

A bit of heat (I just used some hot water) to set the Kapton adhesive and it stays in place really well.

The way you have fixed the switch is you are trying to use the switch to stop the knob from moving which is putting more stress on the switch. It should be the knob that correctly locates the switch. The switch should be free to float a bit.

After this fix, I don't think anyone would notice an issue. I didn't take the tape right to the top and you cannot actually see it at all.

Richard
Title: Re: EEVBlog 121GW Discussion thread
Post by: ChrisG on February 01, 2018, 07:47:20 pm
Appears to have less contamination but we have no idea how many cycles were on the two meters posted so far.   Can you tell with your eyes if any of that is metallic?
I posted the first pictures and checked today. I think it's not metallic at least not magnetic. I checked with a strong neodyn magnet and it doesn't feel metallic.

I cleaned it and will check in some weeks.
I wouldn't have expected it to be magnetic but it's good to know.

Copper, aluminum, gold etc are non-ferro and this test will not work IMHO.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Towger on February 01, 2018, 08:30:51 pm
I have reattached one of ChrisG's photos with a couple of questions:

(https://www.eevblog.com/forum/testgear/eevblog-121gw-discussion-thread/?action=dlattach;attach=391571)

1) What is the point of the two notches in the outside track?
    Are these to give slightly more resistance when moving the switch from the Off position, however there appears to be an slightly worn segment with no track, so this maybe the 'Off' position.

2) A number of the vias too close to the rubbing line/area of the track for my liking.   Joe's testing has clearly shown the wear caused by vias in the track is a major contributor to early failure of the switch.  There appears to be plenty of space in the other side so this only costs initial design time to be done right.
Title: Re: EEVBlog 121GW Discussion thread
Post by: lowimpedance on February 01, 2018, 10:33:04 pm

So after returning from holiday I thought I would have a look inside at what may be happening with my meter.
What I can see happening with mine to cause my issue was the small flexing of the PCB by the input plugs movement
was causing referred movement at the switch area and since my switch was rather 'sloppy' in its location hole this had caused
either contact or contact location issues on their relevant PCB tracks and thus the mode failures.

Further investigation of the switch rotor showed quite a lot of lateral movement in the PCB locating hole.
So next step was what to do to reduce this lateral 'slop'!.
After removing the PCB from the switch knob I could test fit various rod diameters, (rear ends of twist drills in 0.1mm inc.), to lightly expand
the switch plate plastic fingers that go through the main PCB to remove the slop but still have easy rotational movement.
The best size for my meter was 6.1mm OD. To help alignment further I made the ID be a good sliding fit to the hex shaft of the knob at 5.6mm.
 The resulting sleeve I machined up can be seen in the photo below in its final position (I left it longer so its easily removed.). The material used was PEEK which is
reasonably stiff and has good insulation properties, (I also had it anyway  :P). Did not want to use PTFE which would have been too soft at the cross section used.

As an additional exercise I also cut up some 0.3mm PTFE sheet as spacers under the knob circlip, see photo below. Two pieces provided a good take up
of the space between the housing and the circlip. This reduced the knob free play up and down but allowed some compliance in the well in the top housing and the circlip too
due to the soft flexible nature of the PTFE.

In the following, when I refer to just the "switch", I meant all the parts attached to the circuit board. The "switch rotor" is the knob part attached to the case.

I decided to fix my 121GW wobbly switch up a while ago, but after looking at the mechanism, I took a very different approach. I did look at your method but I think it was making the situation even worse rather then better mechanically.

First, instead of putting a spacer under the circlip, I put a spacer between the switch rotor and the the nylon detent spring so that the circlip was in contact with the case plastic. This lifts the rotor upwards. I didn't make it tight. I just wanted to stop any signifigant vertical movement. The reason for this method was so that the circlip does not press on the switch at all. If you put spacers under the circlip, the circlip is pressing on the switch which I think is wrong. The spacer was actually just many layers of duct tape. I had a punch to make a nice hole in the middle.

But now the switch rotor was even looser. So I added a few strips of Kapton tape around the switch rotor sides to widen it till it stopped wobbling much. You want to change a cone shape that is narrowest at the top to one widest at the top, so start off with a thin strip of tape just near the top side of the switch rotor. Then a thicker one that goes to 2/3 down the rotor sides. Then some that goes around the whole sides. The idea is to increase the switch rotor diameter to the point it can hardly wobble, but still have a tiny clearance to the case. Correctly done and the switch rotor is no stiffer then before.

A bit of heat (I just used some hot water) to set the Kapton adhesive and it stays in place really well.

The way you have fixed the switch is you are trying to use the switch to stop the rotor from moving which is putting more stress on the switch. It should be the switch rotor that correctly locates the switch. The switch should be free to float a bit.

After this fix, I don't think anyone would notice an issue. I didn't take the tape right to the top and you cannot actually see it at all.

Richard

For reference when referring to the rotor, that is the plastic carrier for the contact fingers, the PCB is the Stator and the knob would be the 'clicker plate' just like any rotary wafer switch assembly.
 Okay when making it worse are you referring to the small sleeve or the PTFE under the circlip ?.
For the sleeve i disagree that any additional stress is being applied to the contacts or the PCB. The dimensions of it are carefully chosen by measurement to only
apply enough pressure to the plastic fingers of the rotor body to the PCB hole reducing only lateral free play ,(which in my opinion is excessive ), to a minimum without
adversely effecting the effort required to rotate. This mechanical change guarantees alignment of the switch contacts on the rotor with the PCB stator and how will this
introduce ant further stress on the contacts.
 Now for the PTFE under the circlip, has anyone measured the distance from the top of the rotor body to the underside of the circlip to determine how much distance
there actually is ?. I will admit it has crossed my mind and yet I did not actually do it myself , so as soon as I can I will take the meter apart again I will attempt to get some
measurement done there and post back, as well as try the knob without the PTFE spacers to see if only the sleeve cured my issue or it is indeed needed to apply light pressure to the rotor.
If even that is actually happening with the spacers installed.
Title: Re: EEVBlog 121GW Discussion thread
Post by: amspire on February 01, 2018, 11:05:06 pm

For reference when referring to the rotor, that is the plastic carrier for the contact fingers, the PCB is the Stator and the knob would be the 'clicker plate' just like any rotary wafer switch assembly.
You are right. I used the words switch rotor when I meant knob. I have corrected it.
Quote
Okay when making it worse are you referring to the small sleeve or the PTFE under the circlip ?.
For the sleeve i disagree that any additional stress is being applied to the contacts or the PCB. The dimensions of it are carefully chosen by measurement to only
apply enough pressure to the plastic fingers of the rotor body to the PCB hole reducing only lateral free play ,(which in my opinion is excessive ), to a minimum without
adversely effecting the effort required to rotate. This mechanical change guarantees alignment of the switch contacts on the rotor with the PCB stator and how will this
introduce ant further stress on the contacts.
I believe that when you put the PTFE under the circlip, then the circlip does push downwards on the switch rotor slightly. Not much deflection, but I don't think anything you do on the knob should be pushing the rotor up and down.

The way I have fixed my meter, there is a clear gap between the circlip and the rotor.

As far as the sleeve goes, I do not think you need any reduction in play of the rotor since the hex shaft from the knob locates the position of the rotor. You should have a knob that is centred and doesn't wobble.

If you need the sleeve to help stop the knob from wobbling, then I think you are making the switch rotor do something it shouldn't be doing. Any rotating pressure on the knob is transferred directly to the rotor and the PCB. There is no need for this to be so.
Quote

 Now for the PTFE under the circlip, has anyone measured the distance from the top of the rotor body to the underside of the circlip to determine how much distance
there actually is ?. I will admit it has crossed my mind and yet I did not actually do it myself , so as soon as I can I will take the meter apart again I will attempt to get some
measurement done there and post back, as well as try the knob without the PTFE spacers to see if only the sleeve cured my issue or it is indeed needed to apply light pressure to the rotor.
If even that is actually happening with the spacers installed.
I just observed some deflection, but I didn't measure the amount. I had already decided to go a different way. The best way to measure this deflection may be to measure the height of the rotor clip above the PCB on the component side.

What struck me is that when the front case was away from the switch, the knob was really loose - much worse then when attached to the switch.

The problem is threefold - the circlip allows a big vertical movement, the knob sides have too much clearance and the knob moulding taper is all wrong. The knob hole in the case gets wider at the top, and so the knob should also get wider and not narrower at the top. I wanted a knob that on its own wasn't wobbling and that didn't rely on the tightness of the circlip to stop the wobbling.

Now both our "fixes" are definitely not approved by Dave or the manufacturer, so they are both just our own opinion of a solution. Given that it seems that a new knob is coming, it is probably best to wait if you have no problem right now - just be careful with the knob.
Title: Re: EEVBlog 121GW Discussion thread
Post by: lowimpedance on February 01, 2018, 11:44:41 pm
Indeed the fixes we have done for our own are for a bit of tinkering and not 'approved'. And of course I will use the redesigned assembly when it arrives.
But as I have clearly found on my meter the was a direct link to PCB flexure from only small movement of the probe inputs that caused major issues
on the ohm/diode modes of that switch position that it was completely unusable until I did my version of a fix and now in the interim the functions work.
(note that my 121 meters knob was quite 'wobbly' to start with! so I am not convinced its just the knob and not also the rotor slop at play here too.).
Now purely for my own edification I will see what effect the sleeve has without the PTFE packing. Is most surely not going to damage my meter to have a play
while I wait for the 'approved ' replacement part.
Title: Re: EEVBlog 121GW Discussion thread
Post by: ChrisG on February 02, 2018, 12:58:45 am
Indeed the fixes we have done for our own are for a bit of tinkering and not 'approved'. And of course I will use the redesigned assembly when it arrives.
But as I have clearly found on my meter the was a direct link to PCB flexure from only small movement of the probe inputs that caused major issues
on the ohm/diode modes of that switch position that it was completely unusable until I did my version of a fix and now in the interim the functions work.
(note that my 121 meters knob was quite 'wobbly' to start with! so I am not convinced its just the knob and not also the rotor slop at play here too.).
Now purely for my own edification I will see what effect the sleeve has without the PTFE packing. Is most surely not going to damage my meter to have a play
while I wait for the 'approved ' replacement part.


Gents, all of this is fine for the wobbly knob and rotor action. However it does not address the wear of the knob axis within the PCB. The gunk which was on my PCB tracks (or does it?).
Title: Re: EEVBlog 121GW Discussion thread
Post by: videobruce on February 02, 2018, 02:48:29 am
I hate to ask, but what is so special about this DMM???  ???
One would think by all the posts in now THREE sticky threads that it was the 3rd coming, especially considering these threads are only 3 weeks old.   ::)

Who is the manufacture?  I don't see it listed in that DMM thread thou that hasn't been updated in 8 months.
Title: Re: EEVBlog 121GW Discussion thread
Post by: nidlaX on February 02, 2018, 03:03:02 am
I hate to ask, but what is so special about this DMM???  ???
One would think by all the posts in now THREE sticky threads that it was the 3rd coming, especially considering these threads are only 3 weeks old.   ::)

Who is the manufacture?  I don't see it listed in that DMM thread thou that hasn't been updated in 8 months.
There are three stickies and a ton of posts because it's Dave's multimeter, so this is the primary place to discuss it.

If you haven't learned by now that the multimeter is made by UEi, then you aren't trying hard enough.
Title: Re: EEVBlog 121GW Discussion thread
Post by: videobruce on February 02, 2018, 04:14:15 am
Now I have learned.
Of course if there was specific info, other than some U-Boob video as to whom was making/selling this and a link where to buy it, it would of been apparent. This should of been in the OP, without the ASSUMPTION that EVERYONE here already knows about another multimeter of which there are a hundred already in existence and hundreds more discontinued.

That's almost as bad as using acronyms & abbreviations (that aren't COMMON and often used) in documents without at least stating once what they stand for.  :--

"EEVBlog" doesn't ring a bell as a importer or manufacture.   ::)
Title: Re: EEVBlog 121GW Discussion thread
Post by: nidlaX on February 02, 2018, 04:26:32 am


Now I have learned. O
Of course if there was specific info, other than some U-Boob video as to whom was making/selling this and a link where to buy it, it would of been apparent.
There was an announcement thread. There is a Kickstarter page. There is Google.

I recommend learning how to use the Internet.
Title: Re: EEVBlog 121GW Discussion thread
Post by: mikeselectricstuff on February 02, 2018, 05:41:34 am
"EEVBlog" doesn't ring a bell as a importer or manufacture.   ::)
The clues are out there...
Title: Re: EEVBlog 121GW Discussion thread
Post by: lowimpedance on February 02, 2018, 10:18:37 am
Indeed the fixes we have done for our own are for a bit of tinkering and not 'approved'. And of course I will use the redesigned assembly when it arrives.
But as I have clearly found on my meter the was a direct link to PCB flexure from only small movement of the probe inputs that caused major issues
on the ohm/diode modes of that switch position that it was completely unusable until I did my version of a fix and now in the interim the functions work.
(note that my 121 meters knob was quite 'wobbly' to start with! so I am not convinced its just the knob and not also the rotor slop at play here too.).
Now purely for my own edification I will see what effect the sleeve has without the PTFE packing. Is most surely not going to damage my meter to have a play
while I wait for the 'approved ' replacement part.



Gents, all of this is fine for the wobbly knob and rotor action. However it does not address the wear of the knob axis within the PCB. The gunk which was on my PCB tracks (or does it?).

Are you sure the ''gunk' on the PCB is related to the rotor fit/action in the hole of the PCB ?. Looks more like its related to the contacts wiping action on the gold plated traces, unless I'm
looking at the wrong picture!.
If its related to the abrasion of the rotor plastic there should be noticeable scrape marks on the plastic fingers of the rotor that pass through the PCB hole. One would think this type of multimeter
switch rotor construction would be a problem no matter who's brand it is.
Title: Re: EEVBlog 121GW Discussion thread
Post by: lowimpedance on February 02, 2018, 11:29:19 am
Followup to the above where I said ;
Now purely for my own edification I will see what effect the sleeve has without the PTFE packing.
I have removed the packing and left off the circlip too.  So testing of the diode mode, (which failed to work on my meter when received), it still works with no issues at all from any probe movement or
any lateral or wiggling movement of the knob. So it appears at least for my meter the sleeve HAS fixed the issue I had and the PTFE packers are in fact not needed.
Thus too much lateral free play of the rotor is the problem and not contact pressure on the PCB. (and I'll bet its the same with all others meters doing odd things on other ranges that are not firmware related.).


Using a piece of 0.85mm thick PTFE sheet cut in a thin strip and bent to go into the space between the rotor top and top housing I can see the distance (tested by inserting the 'shim' where the knob would have been) to be close to 0.9mm.
The circlip is 0.6mm thick. So in the stock production meters there is no contact between rotor and circlip.
Picture showing the knob removed from the assembled meter and using a teflon shim to measure the gap between the rotor and hosing.

Edit: To note also the knob is much less 'wobbly or free' in its movement when seated with the sleeve in place and no packing under the circlip. (or even the circlip ! :P)
Title: Re: EEVBlog 121GW Discussion thread
Post by: Kean on February 03, 2018, 08:45:35 pm
I forgot to mention that a couple of days ago I dumped the batteries out of a set top box remote control I need to return and was surprised to see that they were made by UEI. I wonder if the 121GW comes with a UEI battery?

UEI batteries in a remote control would be from a different UEI: Universal Electronics (https://www.uei.com/) vs UEi Test Instruments (http://www.ueitest.com/)
Title: Re: EEVBlog 121GW Discussion thread
Post by: 1anX on February 05, 2018, 09:33:31 am
For anyone interested in Dave candidly discussing the 121GW issues:

 https://theamphour.com/377-debugger-vs-printeffer/

Spoilers: Dave chuckles over the irony of the slow resistance settling time and what he has said about other meters.  He also noted that the slowness was introduced in a late firmware update and he noted that they should have had a formal list of tests to be done for each release.

I'm standing by for the US deliveries....

I had a listen to it myself today, as still no word from Dave or UEi on the current state of the meter's repair and updated firmware!

Seems on the theamphour.com interview, Dave says that UEi have a fix for the hardware switch issues. All the suggestions on this forum thread seem to indicate that a fix is necessary and probably straightforward to implement.

Can anyone provide info on what UEi have come up with to fix the wobbly switch and intermittent contact issue?
Title: Re: EEVBlog 121GW Discussion thread
Post by: amspire on February 05, 2018, 10:22:45 am
Can anyone provide info on what UEi have come up with to fix the wobbly switch and intermittent contact issue?
When UEi release fully tested fixes and upgrades, Dave will announce it.

Like it or not, it does not help anyone if companies release updates and fixes in a bit of a panic. It doesn't help if companies promise solutions before they actually have the complete solution. This is a Kickstarter meter - it is close to a prototype unit. They have made the initial 500 or so meters and found a few problems. If you want a great meter, give UEi time to resolve the issues in a proper manner. This is a normal process. A fix for the knob probably means a new moulding and then it should be properly tested to decide if the mark II knob is right or not. It might be too tight for a good feel. They might have to try a third or fourth knob to get it right. Software updates can actually mean major rewrites that then need to go through a full quality audit and testing.

Do you actually have intermittent contact issues yourself? If not, just use the meter, and when the updates come in a week or a few months, you will have a better meter.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on February 05, 2018, 10:27:00 am
For anyone interested in Dave candidly discussing the 121GW issues:

 https://theamphour.com/377-debugger-vs-printeffer/

Spoilers: Dave chuckles over the irony of the slow resistance settling time and what he has said about other meters.  He also noted that the slowness was introduced in a late firmware update and he noted that they should have had a formal list of tests to be done for each release.

I'm standing by for the US deliveries....

I had a listen to it myself today, as still no word from Dave or UEi on the current state of the meter's repair and updated firmware!

For the third or fourth time now, when I know it's all done and dusted, you'll know.
This stuff doesn't take days to do, it can take weeks.
I have just got a new version that fixes the Low-Z high frequency issue, but I have not tried it yet.
So I think that's most of the software issues now fixed, but we will not be dribbling out updates every few days and they solve an issue, there will be one big update that includes all the software bug fixes.
The hardware switch issue is still waiting on parts delivery.

Quote
Can anyone provide info on what UEi have come up with to fix the wobbly switch and intermittent contact issue?

They have tweaked the dimensions of the white plastic spring assembly and switch assembly I believe.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on February 05, 2018, 12:14:29 pm
For those who might miss it ... I will highlight a couple of points...

For the third or fourth time now, when I know it's all done and dusted, you'll know.
This stuff doesn't take days to do, it can take weeks.
If you seriously look at what is involved in the manufacture of an even moderately complex product, this should be no surprise at all.

Quote
So I think that's most of the software issues now fixed, but we will not be dribbling out updates every few days and they solve an issue, there will be one big update that includes all the software bug fixes.
Getting people to re-flash the firmware 20 times in a month is NOT conducive to a high standard of testing - nor is it an appealing prospect to owners.  It is also bad form.
Title: Re: EEVBlog 121GW Discussion thread
Post by: BravoV on February 05, 2018, 12:28:36 pm
Getting people to re-flash the firmware 20 times in a month is NOT conducive to a high standard of testing - nor is it an appealing prospect to owners.  It is also bad form.

Kids these days tend to love frequent updates, no matter how shitty the update, as long the manufacturer keep pumping out updates every week, they will be happy, just don't know why.  :-//

Just look at popular PC forums on motherboards when these tons of whiners cried/cursed/begged etc for frequent BIOS update just for minuscule non critical bug.  :palm:

Prolly they already used to live with their gadgets that do frequent updates like in smartphone apps ? or worst Win 10 syndrome ?  :-DD

Title: Re: EEVBlog 121GW Discussion thread
Post by: nidlaX on February 05, 2018, 12:52:12 pm
Getting people to re-flash the firmware 20 times in a month is NOT conducive to a high standard of testing - nor is it an appealing prospect to owners.  It is also bad form.
Just look at popular PC forums on motherboards when these tons of whiners cried/cursed/begged etc for frequent BIOS update just for minuscule non critical bug.  :palm:
While I generally agree with you, I disagree that firmware updates for this meter in its current state should be aggregated for months before being released.

1. The meter is essentially in a beta phase of release right now, so frequent updates and testing will help the manufacturer find and fix issues more quickly. Issues are expected to be the norm at this stage.
2. The people who wanted first dibs on this meter are also probably the ones who will tolerate more frequent updates. Better to do rapid revisions with 500 willing guinea pigs now than later on when customers expect a mature product.
3. You can always let people opt-in to a faster firmware release channel. If there's a significant new issue or regression, you can always roll back.
Title: Re: EEVBlog 121GW Discussion thread
Post by: amspire on February 05, 2018, 01:02:50 pm
While I generally agree with you, I disagree that firmware updates for this meter in its current state should be aggregated for months before being released.

1. The meter is essentially in a beta phase of release right now, so frequent updates and testing will help the manufacturer find and fix issues more quickly. Issues are expected to be the norm at this stage.
But the manufacturer also has to provide warranty on these meters and they do not want to have to support 100 different versions of updates.

They haven't released any firmware update officially yet. Until they do, they can still change things. It could be that today, there is a meeting at UEi right now where someone is saying "Our autoranging code is not really capable of managing the needs of this meter, particularly in VA mode. There is no way to fix it. We really have to rewrite the autoranging from scratch."

The last thing they would want is a flood of public complaints, Youtube videos, posts and emails about problems with previous updates that will become absolutely irrelevant when the new code is in place.
Title: Re: EEVBlog 121GW Discussion thread
Post by: IanB on February 05, 2018, 01:50:35 pm
This stuff doesn't take days to do, it can take weeks.

While I generally agree with you, I disagree that firmware updates for this meter in its current state should be aggregated for months before being released.

The suggestion was weeks, not months. Let's not exaggerate.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on February 05, 2018, 02:07:55 pm
For some of the "Now" generation, even saying "tomorrow" will get you howls of disapproval...
Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on February 05, 2018, 02:19:49 pm
... so frequent updates and testing will help the manufacturer find and fix issues more quickly.
Except ... that it won't - necessarily.

Each time a revision of any software is made - especially firmware in a device like this - it should undergo full regression testing to make sure that some little tweak in one place didn't break something somewhere else.

Also, an interim solution may demand a particular behaviour in some aspect of operation - but it is later found that this interim solution to one problem caused other issues.  These other issues could then dictate a different solution, with a different behaviour.

No.  As a software developer, I would NOT be happy about releasing something half-baked, especially when there is pressure to get the whole thing sorted.  The rigmarole in just getting a release out would be a waste of resources.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on February 05, 2018, 02:23:41 pm
https://www.youtube.com/watch?v=uUCQuIp_hzU (https://www.youtube.com/watch?v=uUCQuIp_hzU)
Title: Re: EEVBlog 121GW Discussion thread
Post by: amspire on February 05, 2018, 02:25:16 pm
If a rushed update corrupted the calibration data in the meter, then UEi or Dave would have to organise the recalibration of hundreds of meters located around the world under warranty. Releasing firmware is definitely not to be taken lightly.
Title: Re: EEVBlog 121GW Discussion thread
Post by: 1anX on February 05, 2018, 03:24:49 pm
https://www.youtube.com/watch?v=uUCQuIp_hzU (https://www.youtube.com/watch?v=uUCQuIp_hzU)

Hey, many thanks Dave!

That's the Dave I know and love watching. I for one enjoy watching the meter development process and it getting tested by you along the way. No need for a media blackout and a code of silence being enforced. We members on these forums are mostly technical people and supporters of yours and appreciate being kept in the loop.

Bring us along for the ride as it develops, so we can all learn from the experience.

IMO your selling this meter's attributes short by not showing the features off as they are fixed. I say more videos highlighting what goes on technically to rectify the bugs. Don't discount the tremendous interest in this product. Make these early shortcomings its strengths by highlighting the fixes. I would have thought this is a video bloggers dream opportunity!

Those who seem to want to know nothing about the meters progress, and are more than happy to wait weeks without an update, well they can just view the thread once a month or so. That way all forum members/backers and supporters of the kickstarter project are catered for. 

Food for thought, Dave?
Title: Re: EEVBlog 121GW Discussion thread
Post by: amspire on February 05, 2018, 03:39:39 pm

Bring us along for the ride as it develops, so we can all learn from the experience.

IMO your selling this meter's attributes short by not showing the features off as they are fixed. I say more videos highlighting what goes on technically to rectify the bugs. Don't discount the tremendous interest in this product. Make these early shortcomings its strengths by highlighting the fixes. I would have thought this is a video bloggers dream opportunity!

Those who seem to want to know nothing about the meters progress and are more than happy to wait weeks without an update can just view the thread once a month or so. That way all forum members/backers and supporters of the kickstarter project are all catered for. 

Food for thought, Dave?
Would you like to see daily posts saying "There is no update today" ?

Quite often, there is not much more to say until there is an update released. Dave does actually say a fair bit about the multimeter, but it is spread across many threads. It almost sounds like you want to see a live video feed of Dave discussing problems with UEi. Just don't hold your breath waiting for it.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on February 05, 2018, 03:40:10 pm
That's the Dave I know and love watching. I for one enjoy watching the meter development process and it getting tested by you along the way. No need for a media blackout and a code of silence being enforced. We members on these forums are mostly technical people and supporters of yours and appreciate being kept in the loop.

Bring us along for the ride as it develops, so we can all learn from the experience.

I'm sure Dave will be on top of that ... just remember, he does have other things to do.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on February 05, 2018, 05:48:40 pm
That's the Dave I know and love watching. I for one enjoy watching the meter development process and it getting tested by you along the way. No need for a media blackout and a code of silence being enforced. We members on these forums are mostly technical people and supporters of yours and appreciate being kept in the loop.
Bring us along for the ride as it develops, so we can all learn from the experience.

It's not that easy, I have little visibility in what's going on at UEi, and I am not in a position to demand hourly updates from them.
And whilst it may sound great to have every little thing blogged, that does invariably lead to people trying to micromanage what's happening. That's bad enough when it's my own project and I'm in control of everything and can work on things instantly myself, but when you are dealing with a design team in another country on the other side of the planet, invariably with of priorities, it's even worse.

Quote
IMO your selling this meter's attributes short by not showing the features off as they are fixed. I say more videos highlighting what goes on technically to rectify the bugs. Don't discount the tremendous interest in this product. Make these early shortcomings its strengths by highlighting the fixes. I would have thought this is a video bloggers dream opportunity!

Those who seem to want to know nothing about the meters progress and are more than happy to wait weeks without an update can just view the thread once a month or so. That way all forum members/backers and supporters of the kickstarter project are all catered for. 

Food for thought, Dave?

This is not my first trip down the "publish as it happens" route, why do you think I essentially lost interest in the uSupply? Hint,  hundreds of people telling me to do this and do that doesn't help...
So no, it's not necessarily the "dream opportunity" you might think it is.
Title: Re: EEVBlog 121GW Discussion thread
Post by: exe on February 05, 2018, 11:16:37 pm
Kids these days tend to love frequent updates, no matter how shitty the update, as long the manufacturer keep pumping out updates every week, they will be happy, just don't know why.  :-//

Talking bullshit with confidence and calling other names doesn't add you credibility. Modern software development is not based on waterfall model anymore.

A good process development process starts with automated tests. But even if you do (semi-)manual testing I don't think it takes much time to test it. Besides that, let the user decide if s/she wants a hotfix that wasn't fully tested.

BTW, I guess you completely missed Dave saying that FW is a mess. I believe this is the main reason it's taking so much time to fix trivial problem, nothing else.
Title: Re: EEVBlog 121GW Discussion thread
Post by: FrankBuss on February 05, 2018, 11:22:36 pm
They have tweaked the dimensions of the white plastic spring assembly and switch assembly I believe.

Does it get a new version number, or some minor revision I can see when I want to buy one for the mechanic changes? The bluetooth feature and integrated uCurrent etc. are really something I could use, but non-wobbly dial would be nice.

The autorange of the BM235 looks incredible. My BM257s is only as fast as the 121GW now. But no problem, if I need fast autorange, I can use my Fluke 8842A, which is at least as fast as the BM235. Sometimes fast autorange is important for me, e.g. when I sort a bunch of resistors after some breadboarding.
Title: Re: EEVBlog 121GW Discussion thread
Post by: BravoV on February 05, 2018, 11:33:34 pm
Kids these days tend to love frequent updates, no matter how shitty the update, as long the manufacturer keep pumping out updates every week, they will be happy, just don't know why.  :-//

Talking bullshit with confidence and calling other names doesn't add you credibility. Modern software development is not based on waterfall model anymore.

A good process development process starts with automated tests. But even if you do (semi-)manual testing I don't think it takes much time to test it. Besides that, let the user decide if s/she wants a hotfix that wasn't fully tested.

BTW, I guess you completely missed Dave saying that FW is a mess. I believe this is the main reason it's taking so much time to fix trivial problem, nothing else.

Thanks, point taken ... kiddo.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on February 06, 2018, 01:06:34 am
But even if you do (semi-)manual testing I don't think it takes much time to test it.
Typical armchair expert.  "I don't think" indicates you have no practical knowledge.

Quote
Besides that, let the user decide if s/she wants a hotfix that wasn't fully tested.
This really shows how out of touch you are with practicality, let alone commercial reality.
Title: Re: EEVBlog 121GW Discussion thread
Post by: IanJ on February 06, 2018, 05:10:19 am
All I can say is kudos to Dave for the meter in the first place. It takes balls to go commercial with a product worldwide and there is a lot, lot more work across multiple areas that most folks don't see. Net result it consumes your life for a while.

I agree whilst it's tempting to rush out firmware updates fast it invariably ends up needing a follow-up, then another..........IMHO Dave/UEi's approach is deffo the way to go.......Fairly fast but more importantly gotta be thorough and well tested.

I think Dave and UEi have done a great job so far, the issues being fairly light and easily fixed. No show stoppers.
Can't wait to receive mine.

Ian.
Title: Re: EEVBlog 121GW Discussion thread
Post by: dcac on February 06, 2018, 09:16:36 am
https://www.youtube.com/watch?v=uUCQuIp_hzU (https://www.youtube.com/watch?v=uUCQuIp_hzU)

Thanks for the video Dave, yes the 1.05 FW is noticeably faster than 1.04 and at least as fast as the U1282A. And as expected the Brymen 869 is quite faster but then it also only goes down to 10 milliohms resolution where the 121GW goes down to 1 milliohms.

It would be great if you could do two additional auto-ranging comparisons between 121GW, U1282A and U1272A (and perhaps the Gossen) it would be:

1. AC Volt position, all meters connected in parallel, measuring mains 240volt.       

2. DC Amp position, all meters in series, measuring roughly 4.5A DC current load.

This could be good tests to see if any other slowness quirks is lurking in the 121GW FW.

Title: Re: EEVBlog 121GW Discussion thread
Post by: GameProgrammer79 on February 06, 2018, 10:57:53 am
totally agree, good to taste volts and amps as well.  :-/O

https://www.youtube.com/watch?v=uUCQuIp_hzU (https://www.youtube.com/watch?v=uUCQuIp_hzU)

Thanks for the video Dave, yes the 1.05 FW is noticeably faster than 1.04 and at least as fast as the U1282A. And as expected the Brymen 869 is quite faster but then it also only goes down to 10 milliohms resolution where the 121GW goes down to 1 milliohms.

It would be great if you could do two additional auto-ranging comparisons between 121GW, U1282A and U1272A (and perhaps the Gossen) it would be:

1. AC Volt position, all meters connected in parallel, measuring mains 240volt.       

2. DC Amp position, all meters in series, measuring roughly 4.5A DC current load.

This could be good tests to see if any other slowness quirks is lurking in the 121GW FW.


Title: Re: EEVBlog 121GW Discussion thread
Post by: beanflying on February 06, 2018, 12:54:02 pm
Please no more SOOKING about slow auto ranging it is until a release of official new firmware fairly pointless and the issue more than well known. Design of firmware by committee with no code in front of you and zero direct contact to the manufacturer even more pointless. Please look up the term of WOFTAM, which is exactly what it would be called in business this behavior would additionally earn you an ass kicking. Let Dave/UEI sort it and then let us know.

More importantly is my meter is reading 0.1 mV low in 29.4 degrees and took less than 5 seconds to stabilise unlike the 50+ year old 740B that took 30 minutes+ . Reference against the Agilent measures 5.00021 at 25C :popcorn:

Title: Re: EEVBlog 121GW Discussion thread
Post by: dcac on February 06, 2018, 08:39:14 pm
I’m very convinced it’s up to Dave if he wants to make any further auto-raging comparisons. By his own admission - he just didn’t notice how slow the production model was, possibly his focus was on other problems like ie. the bluetooth interface. But if he now feels confident the 121GW really is on par with comparable DMM’s,  well then - that’s great!

Title: Re: EEVBlog 121GW Discussion thread
Post by: GameProgrammer79 on February 07, 2018, 01:35:11 am
I’m very convinced it’s up to Dave if he wants to make any further auto-raging comparisons. By his own admission - he just didn’t notice how slow the production model was, possibly his focus was on other problems like ie. the bluetooth interface. But if he now feels confident the 121GW really is on par with comparable DMM’s,  well then - that’s great!

Really appreciate the amount of attention it has received and number of issues reported so far. It will definitely get better with each iteration of the firmware. We should not get fussy about bugs, it is every where including large firms like Intel (spectre and meltdown) are not immune to it. There are some 3 billion dollar exploding projects as well (http://www.techradar.com/news/this-is-how-much-samsung-says-itll-lose-on-the-galaxy-note-7-recall (http://www.techradar.com/news/this-is-how-much-samsung-says-itll-lose-on-the-galaxy-note-7-recall))

121GW is future proof, simply because one can change the firmware with ease, firmware bugs are technically fixable. I am not sure if it runs a kernel or simple RTOS, probably community with catch up with alternative firmware before long.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Towger on February 08, 2018, 10:22:34 pm
Dave,

The natives on Kickstarter are starting to get restless.  It would not go a miss to post an update, with links to the video etc.  It should be the primary source of updates, but as they are spread over the forum, Amp Hour, Twitter and YouTube are being missed.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Diosol on February 09, 2018, 10:17:53 am
https://www.youtube.com/watch?v=gtov0o8VTW8 (https://www.youtube.com/watch?v=gtov0o8VTW8)

I also made a quickie of 121GW. Dave's second video got me interested inspecting what happens while measuring resistance with multiple meters.
Fluke 322 clamp meter works a little bit differently and other meters went haywire. Switching lead polarity solved that issue.
Some day I'll do inspection of the voltages while measuring resistance and take a look does the Fluke 322 have reverse polarity.

Insulation tester had the highest current of 1,00 mA and maybe that's why it showed 1,4 MOhms in baseline setup.
Title: Re: EEVBlog 121GW Discussion thread
Post by: joeqsmith on February 14, 2018, 10:20:39 am
I saw your test fixture and it looks pretty good.   I assume printed.  If you wanted to replicate the tests I have been running,  the switch is fully rotated both directions to complete one cycle.  I cycle them 50,000 times in 60 hours while measuring the contact resistance.  If the resistance gets about 1K for 1000 cycles in a row, I abort the test.  Other than that, I just let the run.   Pictures before and after and document if the use any sort of lubrication on the contacts.  That's about it. 

If you don't plan to record the contact resistance, you may want to consider inspecting the contacts every 10,000 cycles like Brymen.

Looking forward to seeing what you decide to do and the end results. 
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on February 14, 2018, 10:51:58 am
https://www.youtube.com/watch?v=QSmiMlWEpy0 (https://www.youtube.com/watch?v=QSmiMlWEpy0)
Title: Re: EEVBlog 121GW Discussion thread
Post by: joeqsmith on February 14, 2018, 11:18:01 am
First, thanks for taking the time to run this test.  Second, thanks for posting how you are running it and the results.  I have been curious if the pads had changed at all.   

Five minutes in, I switched to 1080.   Your 50K cycles would be a half for Brymen and what I am doing but still, what is up with this meter?   There is no way I would have expected to see these results after sending you those original pictures.    Impressive indeed. 

I could try and repeat it assuming the contacts are the same but it's not really going to prove anything.   Thanks again and looking forward to seeing the production parts ran.   
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on February 14, 2018, 11:29:08 am
Five minutes in, I switched to 1080.   Your 50K cycles would be a half for Brymen and what I am doing but still, what is up with this meter?   There is no way I would have expected to see these results after sending you those original pictures.    Impressive indeed. 

I expected worse too, but that's what we got.
I don't know what serial number I sent you, but it would have been around a similar date, so likely exactly the same switch and contacts.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Scottjd on February 14, 2018, 02:55:39 pm
Five minutes in, I switched to 1080.   Your 50K cycles would be a half for Brymen and what I am doing but still, what is up with this meter?   There is no way I would have expected to see these results after sending you those original pictures.    Impressive indeed. 

I expected worse too, but that's what we got.
I don't know what serial number I sent you, but it would have been around a similar date, so likely exactly the same switch and contacts.
If these were the production parts, I would like to try and understand why such a dramatic difference.  I wouldn't have guessed it had more than a thousand cycles on it but for all I know, UEI may have cycle tested it.   Looking back over the pictures, it appears the contacts are what was wearing.  Even looking at the last few that they sent, it looks like something was still going on.  Strange.   

Looking at the video and the large gap in the fingers that rotate the knob, are you sure you are getting the full stroke of the switch?  It looks like it may only rotate 90 degrees.  Still even it that was the case, I would have still expected that area to have a fair amount of wear.   

Just scratching my head.

I’ll add to the head scratching. Or let’s just say thinking out loud.
I agree with Joes counting as this is only a half cycles since a user will turn on, then off and that’s a full cycle. Just like they charging cycles on a battery, charge and discharge for a full cycle.

My questions thinking out loud would be around the way the PLA adapter is mounted to the stepper motor. Seems to me and knowing PLA (it looks like PLA) the part will wear some and if a set screw was used the adapter on the motor will start to slip. I’m not a big fan of PLA for mechanical use from personal experience when I first started doing 3D printing.

Maybe something a little stronger on the adapter with something that also has a little flex like a nylon mix filament. The nylon will allow a little flex without breaking the part, and you can over turn the switch just a little past the off positions. My thinking is most people always turn past the off point, they only let go of the switch because the switch stopped them. I’m not talking crazy over shoot on the switch with massive torque, just a little to replicate real human usage. If you set the controller to over shoot with a PLA part even if it’s made with 100% fill, it will start to stress crack, break, or give away on the tolerances of the whole for the set screw and slip.

But I guess that’s why I’m wondering how the part is held into the stepper motor?
It’s a nice rig, but just might benefit from a few little tweaks?
Scott
Title: Re: EEVBlog 121GW Discussion thread
Post by: 1anX on February 14, 2018, 03:16:51 pm

I agree with Joes counting as this is only a half cycles since a user will turn on, then off and that’s a full cycle. Just like they cling cycles on a battery, charge and discharge for a full cycle.

Hmmm, I disagree with your observation in regards to the operation of this meter!

There is an OFF position at each end of the selector, so in effect a user could easily select a range and then switch OFF by continuing in the same direction. Hence one cycle of the switch is achieved by rotating in one direction.

Regardless of how you view the definition of one cycle, at the very least we now have a measured number of cycles to interpret contact wear!

Its interesting, but of course it needs to be repeated with a production unit which I'm sure will happen just as soon as UEi provide one.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on February 14, 2018, 04:12:39 pm
My questions thinking out loud would be around the way the PLA adapter is mounted to the stepper motor. Seems to me and knowing PLA (it looks like PLA) the part will wear some and if a set screw was used the adapter on the motor will start to slip.

It's not slipping.
That meter did 50,000 genuine rotations.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Scottjd on February 14, 2018, 05:15:22 pm

I agree with Joes counting as this is only a half cycles since a user will turn on, then off and that’s a full cycle. Just like they cling cycles on a battery, charge and discharge for a full cycle.

Hmmm, I disagree with your observation in regards to the operation of this meter!
There is an OFF position at each end of the selector, so in effect a user could easily select a range and then switch OFF by continuing in the same direction. Hence one cycle of the switch is achieved by rotating in one direction.
I see your point. But at the same time I think most users will always go for the same “off” position. Maybe based on if they use the meter mostly for current readings, or voltage readings. With mode selected aside I’m still thinking most people will always go to the left off position if they own more then one meter just based on muscle memory and the fact the most other meters they own also go off to the left.

For me personally I will always turn it off to the left because I’m used to turning my meters off to this direction. I do own one meter that has a dual off just like the 121GW (Digitek DT-4000ZC) and it always goes off to the left. Even if I use a mode on the right side of the range switch it still gets turned off to the left. If I had bought a meter that only turned off to the right and didn’t have a left off option, this would probably annoy me to the point of returning it.

But as you said, either way 25K, or 50K is still a lot of switching, and at least it’s getting tested now before being put back into manufacturing and sold to more people.
So what is that saying, “Better late then never”.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on February 14, 2018, 06:09:21 pm
For me personally I will always turn it off to the left because I’m used to turning my meters off to this direction. I do own one meter that has a dual off just like the 121GW (Digitek DT-4000ZC) and it always goes off to the left. Even if I use a mode on the right side of the range switch it still gets turned off to the left. If I had bought a meter that only turned off to the right and didn’t have a left off option, this would probably annoy me to the point of returning it.

Same.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on February 14, 2018, 06:50:22 pm
Now I need to know if there is or has ever been such a meter?

Near enough

(https://pbs.twimg.com/media/DV-3ZN0WsAAKnOl.jpg:large)
Title: Re: EEVBlog 121GW Discussion thread
Post by: HKJ on February 14, 2018, 07:06:47 pm
For me personally I will always turn it off to the left because I’m used to turning my meters off to this direction. I do own one meter that has a dual off just like the 121GW (Digitek DT-4000ZC) and it always goes off to the left. Even if I use a mode on the right side of the range switch it still gets turned off to the left. If I had bought a meter that only turned off to the right and didn’t have a left off option, this would probably annoy me to the point of returning it.
Same.

Now I need to know if there is or has ever been such a meter?


I have not seen that, but some meters has off at the center.
(http://lygte-info.dk/pic/Southwire/16040T/DSC_3023.jpg)
Title: Re: EEVBlog 121GW Discussion thread
Post by: Hydron on February 14, 2018, 08:03:16 pm
Megger annoyingly do the middle-OFF thing too, but ugh, I think that meter above would win a prize in several "worst meter" categories.
Title: Re: EEVBlog 121GW Discussion thread
Post by: 1anX on February 14, 2018, 08:20:14 pm
Here's one that turns off on the right hand side  :)

http://www.dx.com/p/bside-acm03-auto-range-digital-clamp-meter-multimeter-blue-black-302517#.WoP-K-eYNPY (http://www.dx.com/p/bside-acm03-auto-range-digital-clamp-meter-multimeter-blue-black-302517#.WoP-K-eYNPY)
Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on February 14, 2018, 08:52:14 pm
For me personally I will always turn it off to the left because I’m used to turning my meters off to this direction. I do own one meter that has a dual off just like the 121GW (Digitek DT-4000ZC) and it always goes off to the left. Even if I use a mode on the right side of the range switch it still gets turned off to the left. If I had bought a meter that only turned off to the right and didn’t have a left off option, this would probably annoy me to the point of returning it.
Same.

Now I need to know if there is or has ever been such a meter?

I picked up two of these from the "crap bin" at Jaycar many years ago.  They had problems with the rotary switch.  One I was able to sort out and it has been pretty reliable.  The other was not so inclined - and is buried somewhere.

(https://www.eevblog.com/forum/testgear/eevblog-121gw-discussion-thread/?action=dlattach;attach=394979;image)


(Sorry about the transistor tester)
Title: Re: EEVBlog 121GW Discussion thread
Post by: Scottjd on February 14, 2018, 09:41:55 pm
I have not seen that, but some meters has off at the center.
Do clamp meters count?  Well I have both (left and right), left, top (up), bottom (down), and push button. I can’t find my greenlee meter and I used to have a southwire, but I gave it away. I had to check my old BM235 review video to see what that one was. Now I also wish I never gave away my first RadioShack meter I bought when I was a kid.
But I still didn’t realize until tonight I had this many, and I left out the other 3 harbor freight free meters that are just basically battery testers.
Most of them were given to me, one was found, one was $1 yard sale buy, and the others I bought. One more still on the way that I’m waiting on. I think I have a multimeter problem. But surprisingly no right off switch meters. Even the bottom meters have the power button on the left side.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on February 14, 2018, 09:50:32 pm
Have you checked to make sure you were getting a full cycle with that coupler?

Yes.
Title: Re: EEVBlog 121GW Discussion thread
Post by: ChrisG on February 15, 2018, 05:56:45 am
I'm puzzled now that with my 121GW which I use 2-3 times a week for let's say 20-25 cycles I had gunk, abrasion or wear after a couple of weeks already. Perhaps I should clean it now and then take picture and re-take after a month or so. Btw when switching to Ohms range I have to depress the selector switch in order for the meter to switch on otherwise it beeps and then goes dark.
Title: Re: EEVBlog 121GW Discussion thread
Post by: 1anX on February 15, 2018, 07:59:24 am
I'm puzzled now that with my 121GW which I use 2-3 times a week for let's say 20-25 cycles I had gunk, abrasion or wear after a couple of weeks already. Perhaps I should clean it now and then take picture and re-take after a month or so. Btw when switching to Ohms range I have to depress the selector switch in order for the meter to switch on otherwise it beeps and then goes dark.
Sounds like a good idea to me, take pictures now with cleaned contacts and again later to compare.
Probably a waste of time though, if you consider that you will be receiving new contacts and selector switch in the near future?
Title: Re: EEVBlog 121GW Discussion thread
Post by: ChrisG on February 20, 2018, 09:26:11 pm
I'm puzzled now that with my 121GW which I use 2-3 times a week for let's say 20-25 cycles I had gunk, abrasion or wear after a couple of weeks already. Perhaps I should clean it now and then take picture and re-take after a month or so. Btw when switching to Ohms range I have to depress the selector switch in order for the meter to switch on otherwise it beeps and then goes dark.

Please don't clean it or even take it apart.  Just keep using it until you get your replacement parts.  Then take some new pictures so we can get some feel for how the wear was progressing, if at all. 
 

I will not take it apart anymore althought the selector switch is behaving less well every time I use it. Selecting from left to rigth to the Ohms/Diode range it just dies and have to fiddle the switch to make it work. From right (off) to left it tends to work nearly perfect every time.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Insatman on February 20, 2018, 09:54:08 pm
Here is a post from left field....is the name of this meter the 121GW, some reference to Back to the Future...as in 1.21 Gigawatts?    Just thinking...
Title: Re: EEVBlog 121GW Discussion thread
Post by: Fungus on February 20, 2018, 10:13:59 pm
Here is a post from left field....is the name of this meter the 121GW, some reference to Back to the Future...as in 1.21 Gigawatts?    Just thinking...

There's also a flux capacitor inside...

Title: Re: EEVBlog 121GW Discussion thread
Post by: tautech on February 20, 2018, 10:49:22 pm
Here is a post from left field....is the name of this meter the 121GW, some reference to Back to the Future...as in 1.21 Gigawatts?    Just thinking...
Yes, be very careful not to take it past 88 mph !
Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on February 20, 2018, 10:55:10 pm
Here is a post from left field....is the name of this meter the 121GW, some reference to Back to the Future...as in 1.21 Gigawatts?    Just thinking...

There's no mystery about that.  It absolutely is.  The naming of this meter was discussed in the Supporters Lounge - two years ago.  That's when the name was first put forward .... and Dave jumped at it.

Dave is a BTTF fan boy.  (Not sure if I would call him a tragic.)
Title: Re: EEVBlog 121GW Discussion thread
Post by: Insatman on February 21, 2018, 10:40:14 am
Here is a post from left field....is the name of this meter the 121GW, some reference to Back to the Future...as in 1.21 Gigawatts?    Just thinking...

There's no mystery about that.  It absolutely is.  The naming of this meter was discussed in the Supporters Lounge - two years ago.  That's when the name was first put forward .... and Dave jumped at it.

Dave is a BTTF fan boy.  (Not sure if I would call him a tragic.)

I knew he was a fanboy from his video about the BTTF clock.   Thanks for the verification
Title: Re: EEVBlog 121GW Discussion thread
Post by: 1anX on February 21, 2018, 02:37:33 pm
Heeeeeey Joe...

Ok so theres not much happening with the 121GW! UEi are taking a new years holiday or something?

Lets really go BTTF and I'll provide an insight into what too much time on my hands can do.

I love joeqsmith's meter torture tests, he goes all out and in-depth to provide insights into how accurate and durable a multimeter can be made.

Every time I see a post from Joe I start singing "Hey Joe" in my head but change the words to, "heeeeey joe, where ya gunna go with that meter in your hand, where ya gunna go". Maybe I'm showing my age as probably no one on this forum has ever heard of Jimi Hendrix or his band the Jimi Hendrix Experience.

Jimi was also famous for another song, Purple Haze, and it seems to me a direct connection with joeqsmith. Its obvious why, when Joe hits a meter with his HV spike test the meter explodes into a purple plasma haze.

Its a slow afternoon for me, so just thought I'd share a BTTF memory moment that the 121GW triggered.

Lets hope that UEi and Dave have some good news for us soon on how this meter is coming along!

When the production unit finally ships, I'm really looking forward to it being given the JoeQSmith Experience and singing along while I watch him destroy it, just like Jimi used to do to his guitars  :D
Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on February 21, 2018, 03:24:32 pm
Maybe I'm showing my age as probably no one on this forum has ever heard of Jimi Hendrix.....

Just how old do you think people are here?

I'm sure a lot of us - if not the majority - will have heard of Jimi Hendrix, many will know his music and some will no doubt have been fans.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Insatman on February 21, 2018, 04:08:05 pm
Maybe I'm showing my age as probably no one on this forum has ever heard of Jimi Hendrix.....

Just how old do you think people are here?

I'm sure a lot of us - if not the majority - will have heard of Jimi Hendrix, many will know his music and some will no doubt have been fans.

LOL...I was/am a Jimi fan.   I had the opportunity to visit his grave a number of years ago in the Seattle area.  Still one of the best guitar players ever lived
Title: Re: EEVBlog 121GW Discussion thread
Post by: joeqsmith on February 21, 2018, 11:47:53 pm
Heeeeeey Joe...

Ok so theres not much happening with the 121GW! UEi are taking a new years holiday or something?

Lets really go BTTF and I'll provide an insight into what too much time on my hands can do.

I love joeqsmith's meter torture tests, he goes all out and in-depth to provide insights into how accurate and durable a multimeter can be made.

Every time I see a post from Joe I start singing "Hey Joe" in my head but change the words to, "heeeeey joe, where ya gunna go with that meter in your hand, where ya gunna go". Maybe I'm showing my age as probably no one on this forum has ever heard of Jimi Hendrix or his band the Jimi Hendrix Experience.

Jimi was also famous for another song, Purple Haze, and it seems to me a direct connection with joeqsmith. Its obvious why, when Joe hits a meter with his HV spike test the meter explodes into a purple plasma haze.

Its a slow afternoon for me, so just thought I'd share a BTTF memory moment that the 121GW triggered.

Lets hope that UEi and Dave have some good news for us soon on how this meter is coming along!

When the production unit finally ships, I'm really looking forward to it being given the JoeQSmith Experience and singing along while I watch him destroy it, just like Jimi used to do to his guitars  :D

Heeeeey joe, where ya gunna go with that meter in your hand, where ya gunna go
I'm gunna stuff that old meter
Stuff that old meter into a garbage can
Cause that's where it belongs
Hey joe, I heard you fried your best meter to a crisp
You fried it to a blackened crisp
Yeah
Yes I did, I fried it to a crisp
You know that meter was such a peace of shit
and I gave it the zap
and I fried it
Alright
Zap it one more time again, baby
Yeah!

Hey Joe,
what meter you gonna run now?
Hey Joe,
what meter you gonna run now?
Which one?

Gonna zap that old Fluke
gonna zap that old Fluke with my ESD gun

Ain't no fan boy gonna
put a stop to me
Title: Re: EEVBlog 121GW Discussion thread
Post by: geekGee on February 22, 2018, 07:03:42 am
"Ode to an 87V"    ;D
Title: Re: EEVBlog 121GW Discussion thread
Post by: ChrisG on February 22, 2018, 06:26:07 pm
Gentlemen, as much fun and smiles this all gives it does digress from the topic for me. I would really like to see things from Dave: 1. an overall issue list of all the hardware and software related issues, 2. an update, with tentative dates, on when which issue will be addressed (e.g. I could imagine all to be resolved or some to drop and then re-certification is needed?). 3. how to continue with new issues people will start to find (like say the range-switch PCB tracks wearing down or gunk build-up or .... ). Agree?
Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on February 22, 2018, 07:29:05 pm
Sorry.  As much as I might like an update - there's little point in pushing.

If anything, I'd rather effort be put into addressing the issues than taking time out to give progress reports.  Reporting is one way to waste time - and pressing for it, when it isn't going to change the timetable, is somewhat counterproductive.
Title: Re: EEVBlog 121GW Discussion thread
Post by: ChrisG on February 22, 2018, 08:24:20 pm
Sorry.  As much as I might like an update - there's little point in pushing.

If anything, I'd rather effort be put into addressing the issues than taking time out to give progress reports.  Reporting is one way to waste time - and pressing for it, when it isn't going to change the timetable, is somewhat counterproductive.

Don't think I'm pushing here (a lot). I've not even indicated that my request was a request to change the timetable at all. Taking your suggestion, or perhaps even guidance, it would be great to have a simple list on the issues which are there. If I missed it somewhere here please let me know.
Title: Re: EEVBlog 121GW Discussion thread
Post by: 1anX on February 22, 2018, 08:28:11 pm
Gentlemen, as much fun and smiles this all gives it does digress from the topic for me. I would really like to see things from Dave: 1. an overall issue list of all the hardware and software related issues, 2. an update, with tentative dates, on when which issue will be addressed (e.g. I could imagine all to be resolved or some to drop and then re-certification is needed?). 3. how to continue with new issues people will start to find (like say the range-switch PCB tracks wearing down or gunk build-up or .... ). Agree?

My understanding is that this is the discussion thread, so the little diversion of "Hey Joe" is really just passing time till we get an update. There is another thread, (Issues) for reporting the issues arising from the production meter.

It is also my understanding that the issues raised on the Issues thread are being addressed by UEi. Dave has said that UEi are/were in discussion with the meter chipset's makers for support in rectifying some issues. He also stated that South Korea were affected by the Chinese new years holiday which has only just finished.

I'm guessing Dave will be in a position very soon to provide the release date for the Johnny B Good backers and to update us on all the fixes. From what Dave has said about the first release of meters with faulty switches, the backers will be contacted and arrangements made to replace the meters or the switches.

We are all waiting for Dave to inform us of the situation and he is waiting on UEi to fix and thoroughly test the meter.

Have I missed anything?
Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on February 22, 2018, 09:05:03 pm
2. an update, with tentative dates, on when which issue will be addressed

Sorry, this is just not practical.  Dave is one step closer to the problem solvers - but he is not project manager of them.  To get the information you have mentioned would mean bugging the manufacturer - and that would wreck a working relationship.

Don't think for a nanosecond that Dave is not keen to get these issues resolved as soon as possible - but that doesn't mean he is going to shove stuff out just to appease the noisemakers.  That is a suicidal path.


Be patient.  Dave will give us updates when there is something to report.

It takes as long as it takes.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on February 22, 2018, 09:10:53 pm
PS.  As soon as you put a date on something that has one or more an unknown time components, you might as well stick your head in a noose.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on February 23, 2018, 10:05:30 am
It has been found that the switch contact issues were ultimately caused by a slight PCB thickness difference between the pre-production and production boards.
Pre-production boards were on the high side of the tolerance allowance, and production boards on the low side. Actually, the production board thickness was actually slightly outside of UEi's board spec.
A 0.95mm shim (as has been found by others) is the fix for existing units and current stock boards (i.e. all Kickstarter ones and for sometime afterwards). Future volume production boards shouldn't need a shim however.
Shims are on the way to me now for cycle testing.
Title: Re: EEVBlog 121GW Discussion thread
Post by: amspire on February 23, 2018, 10:27:15 am
It has been found that the switch contact issues were ultimately caused by a slight PCB thickness difference between the pre-production and production boards.
Pre-production boards were on the high side of the tolerance allowance, and production boards on the low side. Actually, the production board thickness was actually slightly outside of UEi's board spec.
A 0.95mm shim (as has been found by others) is the fix for existing units and current stock boards (i.e. all Kickstarter ones and for sometime afterwards). Future volume production boards shouldn't need a shim however.
Shims are on the way to me now for cycle testing.
Does "the low side" mean that the board is too thin? Is the 0.95mm shim meant to be attached to the circuit board? Just confused a bit.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on February 23, 2018, 10:30:35 am
It has been found that the switch contact issues were ultimately caused by a slight PCB thickness difference between the pre-production and production boards.
Pre-production boards were on the high side of the tolerance allowance, and production boards on the low side. Actually, the production board thickness was actually slightly outside of UEi's board spec.
A 0.95mm shim (as has been found by others) is the fix for existing units and current stock boards (i.e. all Kickstarter ones and for sometime afterwards). Future volume production boards shouldn't need a shim however.
Shims are on the way to me now for cycle testing.
Does "the low side" mean that the board is too thin? Is the 0.95mm shim meant to be attached to the circuit board? Just confused a bit.

Yes, on the thin side.
The shim goes between the plastic range switch and the case, as per how others have done their own DIY solution.
For those that want to do it themselves, the shim thickness is 0.95mm.
Title: Re: EEVBlog 121GW Discussion thread
Post by: amspire on February 23, 2018, 10:45:50 am
Does "the low side" mean that the board is too thin? Is the 0.95mm shim meant to be attached to the circuit board? Just confused a bit.

Yes, on the thin side.
The shim goes between the plastic range switch and the case, as per how others have done their own DIY solution.
For those that want to do it themselves, the shim thickness is 0.95mm.
So that means that the fact the board is too thin is not being addressed unless the shim is causing the shaft clip to press down on the switch rotor. It just seems to me that if the board it too thin, there should be a shim under the rotor clip.
Title: Re: EEVBlog 121GW Discussion thread
Post by: 1anX on February 23, 2018, 12:58:24 pm
Does "the low side" mean that the board is too thin? Is the 0.95mm shim meant to be attached to the circuit board? Just confused a bit.

Yes, on the thin side.
The shim goes between the plastic range switch and the case, as per how others have done their own DIY solution.
For those that want to do it themselves, the shim thickness is 0.95mm.
So that means that the fact the board is too thin is not being addressed unless the shim is causing the shaft clip to press down on the switch rotor. It just seems to me that if the board it too thin, there should be a shim under the rotor clip.

Like this picture from forum member lowimpedance previous post?

Title: Re: EEVBlog 121GW Discussion thread
Post by: amspire on February 23, 2018, 01:11:58 pm
Like this picture from forum member lowimpedance previous post?
I think that is the fix Dave is talking about. I am just asking if there should be a shim on the plastic clip on the actual switch rotor on the PCB and not just one on the shaft.

That shim in the photo is certain a way to reduce the wobble in the switch knob which is a second problem.
Title: Re: EEVBlog 121GW Discussion thread
Post by: ChrisG on February 23, 2018, 06:31:29 pm
Like this picture from forum member lowimpedance previous post?
I think that is the fix Dave is talking about. I am just asking if there should be a shim on the plastic clip on the actual switch rotor on the PCB and not just one on the shaft.

That shim in the photo is certain a way to reduce the wobble in the switch knob which is a second problem.

Agree with you. I think the range switch, the plastic knob, could be redesgined a bit so that a wobble is less likely to occur. Let's wait for final testing by Dave and team for a prolonged period 50.000 cycles or more if this is the solution. Nonetheless happy to read that a difference and potential root cause has been identified.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on February 23, 2018, 10:09:49 pm
Like this picture from forum member lowimpedance previous post?
I think that is the fix Dave is talking about. I am just asking if there should be a shim on the plastic clip on the actual switch rotor on the PCB and not just one on the shaft.

That shim in the photo is certain a way to reduce the wobble in the switch knob which is a second problem.

Agree with you. I think the range switch, the plastic knob, could be redesgined a bit so that a wobble is less likely to occur. Let's wait for final testing by Dave and team for a prolonged period 50.000 cycles or more if this is the solution. Nonetheless happy to read that a difference and potential root cause has been identified.

The switch wobble is separate problem that is fixed with a slightly redesigned white plastic indent ring. Backers with existing meters will be shipped a new knob, plastic indent ring, and a shim.
Title: Re: EEVBlog 121GW Discussion thread
Post by: amspire on February 27, 2018, 11:01:37 am
Can someone please measure the input impedance when the mVDC is selected.
It is about 9.9M.
Title: Re: EEVBlog 121GW Discussion thread
Post by: 1anX on February 28, 2018, 06:58:51 pm
Dave commented much earlier on the probability of Murphy playing a role in this meter's fate. The comment that comes to mind ran along the lines of delivery dates could be impacted by such things as the USA coming into conflict with North Korea.

Hopefully UEi can deliver before this comes into operation and hopefully diplomacy will find a way. https://www.washingtonpost.com/opinions/trumps-team-is-floating-an-attack-on-north-korea-americans-would-die/2018/02/27/8e6cdf66-1826-11e8-92c9-376b4fe57ff7_story.html?utm_term=.5808f5ad42ac (https://www.washingtonpost.com/opinions/trumps-team-is-floating-an-attack-on-north-korea-americans-would-die/2018/02/27/8e6cdf66-1826-11e8-92c9-376b4fe57ff7_story.html?utm_term=.5808f5ad42ac)
Title: Re: EEVBlog 121GW Discussion thread
Post by: Bud on February 28, 2018, 07:13:20 pm
Stay away from politics.
Title: Re: EEVBlog 121GW Discussion thread
Post by: JonM on March 03, 2018, 04:58:16 am
I was away and missed the live stream. Upon returning last night I saw the pop-up notification which took me to a recording of the live stream. David2's "plot" was there, shortly before Dave has to leave he holds a tablet up to the camera. First was pass/fail data, then a bit later "raw" data. I think that there was some good explanation of why some data are bad. In the reproducible research world (if making a document), it is best to show two plots with one including the "bad" data and the explanation of why it is bad. You don't want the scale set so that "real" variation cannot be seen. Of course, I don't think that they are planning a document on the testing.
Title: Re: EEVBlog 121GW Discussion thread
Post by: bitwelder on March 04, 2018, 12:36:35 am
Any plans regarding sigrok support for this meter?
Title: Re: EEVBlog 121GW Discussion thread
Post by: Tinkerlad on March 04, 2018, 10:40:57 am
Any plans regarding sigrok support for this meter?

Once I get my hands on one I will be looking at adding sigrok support if someone hasnt already. Im also very interested in seeing what sort of data throughput the BT module can get and if I can get a low data rate stream over Bluetooth into sigrok lol.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on March 04, 2018, 10:55:19 am
If you go back now and look, it appears the data was removed.  I watched it after it was live and assume it would have had to been cut and reloaded.

No, that's not how Youtube live streams work. It records the whole thing and makes it available afterwards. I did not edit it or even upload it.

Quote
Strange as I don't remember it being anything that I considered that out of the ordinary.  They were messing with the jig a fair amount and maybe just want to show a clean data set.  It sounded like they may run a few other meters as well.

No, we only ran the one meter.
Title: Re: EEVBlog 121GW Discussion thread
Post by: 1anX on March 04, 2018, 06:11:53 pm
That's odd.  I know I saw the plots the first time I watched the videos. Maybe I am just not able to find it.

Hey Joe, are you going to be getting a production run meter from the next batch?

The first release meters even to backers were really prototypes, so the next batch will really be the first production run released having undergone substantial testing.

I'm hoping to see you test the new updated meter and look forward to your unbiased results!
Title: Re: EEVBlog 121GW Discussion thread
Post by: IanB on March 05, 2018, 04:03:45 am
I really have not seen a lot of testing going of of these first meters, not like I had hoped for anyway.   It's premature to think about it.

I think the timing of the Kickstarter announcement made it most accessible to people in the USA (it was in the middle of the night in Europe), so many (even most?) orders came from here. And as you know, the USA batch has not been delivered yet. I think you can expect to see much more discussion and testing once the USA meters get into people's hands.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on March 05, 2018, 11:50:19 am
Results from the 50,000 cycles with the shim solution

https://www.youtube.com/watch?v=u2-ot2vWLxI (https://www.youtube.com/watch?v=u2-ot2vWLxI)

Title: Re: EEVBlog 121GW Discussion thread
Post by: TheSteve on March 05, 2018, 12:20:37 pm
Very cool! The results are pretty darn good for 50K cycles.

Going to have a giveaway for the highest use 121GW in existence?
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on March 05, 2018, 12:30:47 pm
Going to have a giveaway for the highest use 121GW in existence?

Fraid not, we only have two beat up meters in the lab.
Title: Re: EEVBlog 121GW Discussion thread
Post by: amspire on March 05, 2018, 12:59:28 pm
If you put some thin Kapton tape on both sides of the spacer and heat it to set the glue, it would probably stop the abrasion.

The normal tape is HN Kapton. There are non-Dupont FEP coated (teflon) polyimide tapes available. I just do not know if the Kapton FN (FEP coated) film is available as a tape.

Two layers of Kapton tape varies in total thickness between 0.13 mm for the 1mil tape to 0.23mm for the 3mil tape. Not sure if 0.13mm is too much or not - may have to thin the spacer a little. If you only add the tape between the spacer and the case, the thickness can drop to 0.065mm.

I have also mentioned before the method I used with polyimide tape around the outside of the knob to reduce clearance between the knob and the case so it cannot wobble much. Seems to work great. You can reverse the camber of the knob edges to match the case.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on March 05, 2018, 01:11:22 pm
UPDATE: We completely screwed the pooch! We installed the shim upside down!
There was supposed to be no contact friction between the shim and the plastic case (which created all the dust). Apparently we were too dumb to read UEI's instructions precisely. Doh.?  :palm:
Title: Re: EEVBlog 121GW Discussion thread
Post by: amspire on March 05, 2018, 01:14:45 pm
UPDATE: We completely screwed the pooch! We installed the shim upside down!
There was supposed to be no contact friction between the shim and the plastic case (which created all the dust). Apparently we were too dumb to read UEI's instructions precisely. Doh.?  :palm:
Why have they routed the recess then? It isn't meant to fit between the case and the clip, is it? Otherwise it seems they have thinned the part of the spacer taking all the force.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on March 05, 2018, 03:12:06 pm
Why have they routed the recess then?
That's the question that came to my mind as well.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on March 05, 2018, 06:24:19 pm
UPDATE: We completely screwed the pooch! We installed the shim upside down!
There was supposed to be no contact friction between the shim and the plastic case (which created all the dust). Apparently we were too dumb to read UEI's instructions precisely. Doh.?  :palm:
Why have they routed the recess then? It isn't meant to fit between the case and the clip, is it? Otherwise it seems they have thinned the part of the spacer taking all the force.

The recess fits over the protruded tab on the actual top of the range switch, I showed this on the latest live feed.
The circlip actually resides flush with the case as it's in a concave part of the case molding.
Title: Re: EEVBlog 121GW Discussion thread
Post by: 1anX on March 05, 2018, 08:12:37 pm
The recess fits over the protruded tab on the actual top of the range switch, I showed this on the latest live feed.
The circlip actually resides flush with the case as it's in a concave part of the case molding.

How about a link Dave!
I couldn't find the live feed where you show the correct position of the spacer.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on March 05, 2018, 09:11:52 pm
The recess fits over the protruded tab on the actual top of the range switch, I showed this on the latest live feed.
The circlip actually resides flush with the case as it's in a concave part of the case molding.

How about a link Dave!
I couldn't find the live feed where you show the correct position of the spacer.

You'll see it eventually in a saved live feed. live streams only go back 2 hours.
Title: Re: EEVBlog 121GW Discussion thread
Post by: amspire on March 06, 2018, 12:42:48 am
If you want to compare it with the Fluke 17B+, SC4.   I have no answer why this meter is so stable. The contacts are a whole different setup. 
I wonder if the resistance connections going through the switch are 4 wire in the Fluke. It is one possible explanation for the dramatic improvement in performance over all the other meters.

It is also possible that they have put in the engineering work needed to make fabulous switches.
Title: Re: EEVBlog 121GW Discussion thread
Post by: 1anX on March 06, 2018, 04:14:54 pm
Watching Dave's switch testing live video earlier on today. Had the spacer on the right way round this time  :D
Looks like the switch is fixed and thoroughly tested!
All we need to find out now is have the firmware fixes been applied and tested?
Must be getting close to shipping out to the Johnny Be Goode backers  :-+
Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on March 06, 2018, 04:35:44 pm
You're keen.

I can understand that to a point - but if we take it to an automotive equivalent ... adding a packing piece that helps keep the steering wheel from wobbling around and properly connected to the steering rack doesn't mean the rewrite of the engine management system is nearly finished.

You are not the only one anxious for the updates to go out.

Also, just remember those who did get the meters, got them at a reduced price.  That came with a risk, one that was pretty much expected by many.  When I'm able to get one of these for myself, I will be paying more in dollar terms, but less in time.
Title: Re: EEVBlog 121GW Discussion thread
Post by: 1anX on March 06, 2018, 07:29:52 pm
Also, just remember those who did get the meters, got them at a reduced price.  That came with a risk, one that was pretty much expected by many.  When I'm able to get one of these for myself, I will be paying more in dollar terms, but less in time.
Well I dunno about that Brumby! I think you have invested plenty of time on this thread already :D

Your comments are plentiful and you usually dont spare us the depth of your insights into how this meter should or shouldn't be developed and what should or shouldn't take place before its released as a production unit.

I personally decided to place an order, (become a backer) because of its novelty value and because of it coming from Dave and EEVBlog. I paid whatever for the meter and ended up in the Johnny Be Goode group. I make no pretense of being privy to the design and release of this meter just my own thoughts and observations. If the meter works out to be great value for money I will be well pleased.

As this forum is for Discussion I will continue to discuss and share my thoughts with those who care to read them. I dont pretend to be an expert in meter design and testing, I'm simply interested in this meter and Dave's kick starter venture. For me its about a meter and its development and having fun while discovering whats involved.

In a discussion, its not only "expert" opinion that makes for interest, drawing a cross section of personalities and opinions makes it more diverse and complete.
Title: Re: EEVBlog 121GW Discussion thread
Post by: joeqsmith on March 06, 2018, 09:40:17 pm
Dave, I mentioned I had uploaded  a few clips of  Brymen's test jig in operation.  The attached link starts at those clips.  It is followed by showing how my setup works.

Also, the formulas on the yellow sticky notes were r=v/2300 and R=2740/((1/r)-1) . The second note stated the first column was V.    So for v=128,  R=2740/((2300/128)-1) = 152.5.  But this is way too high.  Even if it were 1.525  ohms, this is not close.   With all that computer power, I am a bit surprised that the software just did not display the value in ohms rather than use bits of paper.   Your programmer needs to step up their game.   :-DD

 
https://youtu.be/bs5n3a__Yq0?t=400
Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on March 07, 2018, 12:48:25 am
Your comments are plentiful and you usually dont spare us the depth of your insights into how this meter should or shouldn't be developed and what should or shouldn't take place before its released as a production unit.
Sorry.

I just made comments about the development process as I see it, based on what little I know, what Dave has said and what logic suggests.

I take any comment that infers the process should be in such-and-such a state as something a little more aggressive than "a hope".  It will take as long as it takes.
Title: Re: EEVBlog 121GW Discussion thread
Post by: 1anX on March 07, 2018, 08:06:52 am
Dave, I mentioned I had uploaded  a few clips of  Brymen's test jig in operation.  The attached link shows starts at those clips.  It is followed by showing how my setup works.
https://youtu.be/bs5n3a__Yq0?t=400

Joe, watching the video of your test jig in action, it becomes apparent just how brutal Dave's jig is compared to yours. Your switch actuating "fingers" and timed sequencing approximates real world usage. At least it appears that way to me.

It suggests to me that Dave's jig would inflict more wear and damage than may be found in other manufacturers testing of their meter's switches?

It also shows the relevance of having someone like you running uniform consistent tests on a range of meters and brands so that a true indication of robustness, precision and accuracy can be conveyed to the prospective buyer.

Definitely looking forward to seeing how the blue meter performs once you get hold of a "production" unit.

Watching the video also presented me with the same dilemma that confronted Neo. Choose the Red meter or the Blue meter, as I considered the Brymen a worthy competitor for my money!
Title: Re: EEVBlog 121GW Discussion thread
Post by: joeqsmith on March 07, 2018, 12:17:03 pm
Dave, I mentioned I had uploaded  a few clips of  Brymen's test jig in operation.  The attached link shows starts at those clips.  It is followed by showing how my setup works.
https://youtu.be/bs5n3a__Yq0?t=400

Joe, watching the video of your test jig in action, it becomes apparent just how brutal Dave's jig is compared to yours. Your switch actuating "fingers" and timed sequencing approximates real world usage. At least it appears that way to me.

It suggests to me that Dave's jig would inflict more wear and damage than may be found in other manufacturers testing of their meter's switches?

It also shows the relevance of having someone like you running uniform consistent tests on a range of meters and brands so that a true indication of robustness, precision and accuracy can be conveyed to the prospective buyer.

Definitely looking forward to seeing how the blue meter performs once you get hold of a "production" unit.

Watching the video also presented me with the same dilemma that confronted Neo. Choose the Red meter or the Blue meter, as I considered the Brymen a worthy competitor for my money!

I am not really sure which setup would be harder on the meter or closer simulate real world use or even if it matters.   I can only show what I am doing, present the data and let the viewers draw their own conclusions.  Similar to the transient tests.  As you suggest, I do try and keep the tests consistent and there does seem to be some trends even with the limited data I have collected.   One benefit is because I really don't care about hand held meters and have no vested interest in any brand and draw no income from running them, coupled with a somewhat consistent set of tests, things are fairly unbiased.   You get data rather than feelings. 

blah blah blah....

Now about those yellow sticky notes.   I saw they were no longer shown in the edited video so I have attached a screen shot.  Granted, I am not sure why they use r=V/3300 only to invert it below but the numbers don't seem to work out even close to what their meter was reading and everything is well above the 10 ohm limit.  Is this that new math I keep hearing about? 
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on March 07, 2018, 01:56:28 pm
Now about those yellow sticky notes.   I saw they were no longer shown in the edited video so I have attached a screen shot.  Granted, I am not sure why they use r=V/3300 only to invert it below but the numbers don't seem to work out even close to what their meter was reading and everything is well above the 10 ohm limit.  Is this that new math I keep hearing about?

a) Nothing was "removed in editing". The entire original 23 hour video is still being processed by youtube and will eventually be available online. It seems that only the final 2 hours is currently available.

b) By the "edited video" I presume you mean the one "How to do Lifecycle Testing". I simply extracted some content from the stream to create a new video were I talked about general range switch testing as I thought it might be interesting to people as separate video.

c) There is a uCurrent x100 amplifier used in the jig across the switch contacts, that is not shown in the equations.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on March 07, 2018, 02:11:29 pm
UPDATE:

Hardware:
- We are now confident in the shim and revised indent spring solution for the range switch. This fixes both the intermittent contact issue and the switch wobble issue.
- Existing backers with meters will get shipped a replacement switch and shim and instructions.
- All future backer meters shipped will come with these installed.

Firmware
- We will now release version 1.07 it can be downloaded here:
https://www.eevblog.com/product/121gw/ (https://www.eevblog.com/product/121gw/)
Just rename it to EEVblog.bin on the SD card and update as per the manual instructions.
This fixes several major issues including:
- Improved ohms autoranging speed, now on par with the Keysight U1282A
- Negative VA value issue
- Beeper now defaults to off and can be switched on in the setup menu.
- High frequency Low-Z measurement issue fixed.
- VA over reading issue fixed.

Software
- Windows app software is now available on the Microsoft store.

Barring any more issues we will be proceeding with fulfillment again shortly. Sorry, no ETA actual dates will be promised at this stage.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Average Meatsack on March 07, 2018, 04:41:26 pm
UPDATE:

Software
- Windows app software is now available on the Microsoft store.

I have downloaded the software onto my Windows 10 laptop. I am waiting for my meter but I thought I would have a quick poke around the software beforehand. I would have though that it would be similar to the Android version that actually has a display but no such luck. All I get when I start the software is a window with <Settings> and a refresh button at the bottom of the screen. Clicking on <> or Settings does nothing. Mousing over the Reset button causes a change colour but it is impossible to know if it is doing anything.

I am using Windows 10 Build 1629.248, 8Gb RAM, Core i5-4200U CPU and with plenty of space on the Windows OS install partition. Bluetooth is enabled. I tried disabling Avast to see it that was causing the seeming issue but there was no change. I believe I am having an issue with the software unless it behaves completely different to the Android version, not displaying anything if it cannot see the meter.

I have attached a screenshot of what I am seeing.
Title: Re: EEVBlog 121GW Discussion thread
Post by: imidis on March 07, 2018, 05:16:42 pm
That looks like a typical windows 10 app to me.  >:D :-//
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on March 07, 2018, 05:40:32 pm
I have downloaded the software onto my Windows 10 laptop. I am waiting for my meter but I thought I would have a quick poke around the software beforehand. I would have though that it would be similar to the Android version that actually has a display but no such luck. All I get when I start the software is a window with <Settings> and a refresh button at the bottom of the screen. Clicking on <> or Settings does nothing.

It shouldn't display anything unless you have a meter to talk to, sorry.
Title: Re: EEVBlog 121GW Discussion thread
Post by: bitwelder on March 07, 2018, 05:47:53 pm
F/w 1.07: the Sound of Silence  :-+
Title: Re: EEVBlog 121GW Discussion thread
Post by: amspire on March 07, 2018, 05:55:47 pm
F/w 1.07: the Sound of Silence  :-+
I was going to post earlier but hit a stumbling block.

After loading 1.07, I found my current ranges no longer work. Put it back to 1.01 and they still do not work - reads overflow on many ranges. I am debugging the meter to see if I just got a switch problem at the same time as the upgrade. The meter has not been near high voltages and currents and the fuses and shunts are fine. The current ranges did work perfectly. It is not a lost calibration issue - it looks more like a floating connection that should be going to the shunt resistors.

The resistance  now goes from open to a short in under 5 seconds - much more respectable.  :-+

Looks like VA is still restricted to 55V maximum and they haven't fixed the issues with the capacitance manual range yet:
https://www.eevblog.com/forum/testgear/eevblog-121gw-multimeter-issues/150/ (https://www.eevblog.com/forum/testgear/eevblog-121gw-multimeter-issues/150/)
Title: Re: EEVBlog 121GW Discussion thread
Post by: 1anX on March 07, 2018, 06:57:24 pm
F/w 1.07: the Sound of Silence  :-+
I was going to post earlier but hit a stumbling block.

After loading 1.07, I found my current ranges no longer work. Put it back to 1.01 and they still do not work - reads overflow on many ranges. I am debugging the meter to see if I just got a switch problem at the same time as the upgrade. The meter has not been near high voltages and currents and the fuses and shunts are fine. The current ranges did work perfectly. It is not a lost calibration issue - it looks more like a floating connection that should be going to the shunt resistors.

The resistance  now goes from open to a short in under 5 seconds - much more respectable.  :-+

Looks like VA is still restricted to 55V maximum and they haven't fixed the issues with the capacitance manual range yet:
https://www.eevblog.com/forum/testgear/eevblog-121gw-multimeter-issues/150/ (https://www.eevblog.com/forum/testgear/eevblog-121gw-multimeter-issues/150/)

Bugger!

Interested to see what you find the problem is with your current ranges.

Thanks for reporting the capacitance reading problem. Looking at your previous post you think this is associated with the oscillator not having a time out function and more specifically a time out function suited to the range selected.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on March 07, 2018, 11:12:51 pm
After loading 1.07, I found my current ranges no longer work. Put it back to 1.01 and they still do not work - reads overflow on many ranges. I am debugging the meter to see if I just got a switch problem at the same time as the upgrade. The meter has not been near high voltages and currents and the fuses and shunts are fine. The current ranges did work perfectly. It is not a lost calibration issue - it looks more like a floating connection that should be going to the shunt resistors.

I would presume that has to a coincidental intermittent switch issue. No other reason would make sense.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Iagash on March 07, 2018, 11:23:09 pm
The bluetooth data corruption is not fixed in 1.07.

Some can be detected, but others can't, see the random "LowZ" signaling in the 6th column.

Quote
1520424876.136 2017-08 00042    Power DC (VA)     0.0 mVA       DCA    0.01
1520424876.406 2017-08 00042    Power DC (VA)     0.0 mVA       DCA    0.01
1520424876.676 read STDIN: invalid byte: 6 of 34
1520424876.676 read STDIN: invalid byte: 13 of 20
1520424876.676 read STDIN: invalid byte: 10 of 19
1520424876.811 read STDIN: invalid byte: 10 of 14
1520424877.081 2017-08 00042    Power DC (VA)     0.3 mVA       DCA    0.01
1520424877.352 2017-08 00042    Power DC (VA)     0.3 mVA       DCA    0.01
1520424877.621 read STDIN: invalid byte: 131 of 34
1520424877.621 read STDIN: invalid byte: 10 of 33
1520424877.756 read STDIN: invalid byte: 10 of 14
1520424878.026 2017-08 00042    Power DC (VA)     0.0 mVA       DCA    0.01
1520424878.296 2017-08 00042    Power DC (VA)     0.0 mVA       DCV  0.0000
1520424878.566 2017-08 00042    Power DC (VA)     0.0 mVA       DCV  0.0000
1520424878.836 2017-08 00042    Power DC (VA)     0.1 mVA       DCV  0.0000
1520424879.106 2017-08 00042    Power DC (VA)     0.1 mVA       DCV  0.0000
1520424879.376 2017-08 00042    Power DC (VA)     0.1 mVA     Low_Z    4112
1520424879.646 read STDIN: invalid byte: 10 of 34
1520424879.781 2017-08 00042    Power DC (VA)     0.0 mVA       DCV  0.0000
1520424880.051 2017-08 00042    Power DC (VA)    -0.4 mVA       DCV  0.0000
1520424880.321 2017-08 00042    Power DC (VA)    -0.4 mVA       DCV  0.0000
1520424880.591 2017-08 00042    Power DC (VA)     0.0 mVA       DCV  0.0000
1520424880.861 2017-08 00042    Power DC (VA)     0.0 mVA       DCV  0.0000
1520424881.131 read STDIN: invalid byte: 24 of 34
1520424881.131 read STDIN: invalid byte: 13 of 19
1520424881.131 read STDIN: invalid byte: 10 of 18
1520424881.266 read STDIN: invalid byte: 20 of 14
1520424881.266 read STDIN: invalid byte: 10 of 13
1520424881.536 read STDIN: invalid byte: 10 of 14
1520424881.806 2017-08 00042    Power DC (VA)     0.0 mVA       DCA    0.01
1520424882.076 2017-08 00042    Power DC (VA)     0.0 mVA       DCA    0.01
Title: Re: EEVBlog 121GW Discussion thread
Post by: Candid on March 07, 2018, 11:33:46 pm
- Existing backers with meters will get shipped a replacement switch and shim and instructions.
Thank you I am eagerly waiting for this fix!

Firmware
- We will now release version 1.07 it can be downloaded here:
Thank you for the new firmware, works fine for me and auto range is really ok now even if it is not the fastest (for me max. 4 - 5 secs).

The beeper off function needs a revise I think. Now at beeper off you don't have any beeper in all functions. No continuity beeper and no beeper in any other function.

It would be much better to get a detailed beeper configuration at least should (if only one is possible) beeper off only be for power on and switching between the functions with the switch. When I power on the 121GW I automatically look on the display and see if it turns on, no need for a beep. And when I switch the function I get a feedback from the switch and the display, no need for a beep. But in continuity and other functions I need the beep as feedback even if the display gives me a feedback too but I am not always looking on the display when using this functions (e.g. searching for a short).
Title: Re: EEVBlog 121GW Discussion thread
Post by: amspire on March 08, 2018, 12:03:00 am
After loading 1.07, I found my current ranges no longer work. Put it back to 1.01 and they still do not work - reads overflow on many ranges. I am debugging the meter to see if I just got a switch problem at the same time as the upgrade. The meter has not been near high voltages and currents and the fuses and shunts are fine. The current ranges did work perfectly. It is not a lost calibration issue - it looks more like a floating connection that should be going to the shunt resistors.

I would presume that has to a coincidental intermittent switch issue. No other reason would make sense.
That's what I figured, but my initial look at the circuit showed a lot of the current switching is done by cmos switches. Both the buffered and unbuffered ranges are affected. The rotary switch seems to be perfect. I cannot find any obvious continuity faults right now. I will hook up some power and test the voltages tomorrow. It might be a broken track or a dry joint.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Iagash on March 08, 2018, 12:05:40 am
Bluetooth and VA mode is still completely broken, even if you filter the invalid records.
It's also broken in the android app. It displays the same wrong readings.

The 391.2 mVA reading is the correct one.

Quote
1520427022.717 2017-08 00042    Power DC (VA)  2499.9 mVA       DCV  1.5652
1520427022.987 2017-08 00042    Power DC (VA)  2499.8 mVA       DCV  1.5652
1520427023.257 2017-08 00042    Power DC (VA)  2499.8 mVA       DCV  1.5652
1520427023.527 2017-08 00042    Power DC (VA)  2499.8 mVA       DCV  1.5652
1520427023.797 2017-08 00042    Power DC (VA)   391.2 mVA       DCV  1.5652
1520427024.067 2017-08 00042    Power DC (VA)   391.2 mVA       DCV  1.5652
1520427024.742 2017-08 00042    Power DC (VA)  1564.9 mVA       DCA  249.97
1520427025.282 2017-08 00042    Power DC (VA)  1565.2 mVA       DCA  249.97
1520427025.552 2017-08 00042    Power DC (VA)   391.2 mVA       DCA  249.97
1520427025.822 2017-08 00042    Power DC (VA)  2500.0 mVA       DCA  249.97
1520427026.565 2017-08 00042    Power DC (VA)  2499.9 mVA       DCA  249.97
1520427027.240 2017-08 00042    Power DC (VA)   391.3 mVA       DCA  249.99
1520427027.510 2017-08 00042    Power DC (VA)   391.3 mVA       DCA  249.99
1520427027.780 2017-08 00042    Power DC (VA)  1521.7 mVA       DCV  1.5653
1520427028.050 2017-08 00042    Power DC (VA)  1565.2 mVA       DCV  1.5653
1520427028.320 2017-08 00042    Power DC (VA)  1565.2 mVA       DCV  1.5653
1520427029.265 2017-08 00042    Power DC (VA)  2500.2 mVA       DCV  1.5655
1520427029.535 2017-08 00042    Power DC (VA)  2500.0 mVA       DCV  1.5655
1520427029.805 2017-08 00042    Power DC (VA)  2500.1 mVA       DCV  1.5655
1520427030.075 2017-08 00042    Power DC (VA)  2500.0 mVA       DCV  1.5655
1520427030.345 2017-08 00042    Power DC (VA)  2500.1 mVA       DCV  1.5655
1520427031.020 2017-08 00042    Power DC (VA)  1516.9 mVA       DCV  1.5655
1520427031.290 2017-08 00042    Power DC (VA)  1516.9 mVA       DCA  250.00
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on March 08, 2018, 12:09:56 am
The 24 hour video was no longer listed when I checked, so yes I was referring to your how-to video.   

Youtube is rooted, it's there.

https://www.youtube.com/watch?v=VzS6coxYSAs (https://www.youtube.com/watch?v=VzS6coxYSAs)

It's still processing

(https://i.imgur.com/F5gGpQZ.png)
Title: Re: EEVBlog 121GW Discussion thread
Post by: idpromnut on March 08, 2018, 12:49:39 am
@Dave: at the risk of sounding like an ungrateful asshole, while the beeper on/off option is fantastic (nice and quite now!  :-+ ), it renders the continuity beeper also silent, which I would argue either should have it's own configuration option, or at least be on all the time, even if the beeper for functions/buttons is turned off.

That being said, I don't know that I would classify this as an "issue".  A big thanks to UEi for getting issues in the FW addressed quickly!
Title: Re: EEVBlog 121GW Discussion thread
Post by: Candid on March 08, 2018, 01:26:10 am
Maybe someone can explain to me what the problem is:
2 different function generators tested, JDS6600 and FeelTech FY6600. Identical settings, identical results.

For example: 4kHz square wave with 2.0Vpp. Measured Vac with the 121GW and as comparison a Fluke 28II (highres mode).

Range AUTO: 121GW selects 5V range, Fluke selects 6V range
121GW reads 1.37xxVac, Fluke reads 0.99xxVac

Manual range 5V 121GW, 6V Fluke 28II:
121GW reads 1.37xxVac, Fluke reads 0.99xxVac

Manual range 50V 121GW, 60V Fluke 28II:
121GW reads 0.95xVac, Fluke reads 0.94xxVac

Similar behavior for the 121GW with sine wave. It reads 1,117xV in auto range and manual 5V range and 0,664V in manual 50V range. I checked with 200Hz sine and same behavior for the 121GW, Fluke and Brymen 235 work fine.

What is the 121GW doing in auto range / 5V range?


And Bluetooth:
Still the same for me. It's more or less luck if I get a connection to the meter. Tried both apps. When I get a connection with Dave2-App I only get something displayed in the lower half of the display, the upper half stays completely blank for me on my Samsung Galaxy S8.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Iagash on March 08, 2018, 01:27:48 am
@Dave: at the risk of sounding like an ungrateful asshole, while the beeper on/off option is fantastic (nice and quite now!  :-+ ), it renders the continuity beeper also silent, which I would argue either should have it's own configuration option, or at least be on all the time, even if the beeper for functions/buttons is turned off.

That being said, I don't know that I would classify this as an "issue".  A big thanks to UEi for getting issues in the FW addressed quickly!

On first thought I'd also say that the continuity beep should be always on. But on second thought it's maybe a matter of taste.

A bonus would be a blinking backlight if the continuity beep is off.

Anyways thanks for the beeper option.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Hydron on March 08, 2018, 02:29:44 am
 I personally think the beeper is necessary in the following circumstances:
- Continuity (which even uses the sound symbol!)
- Diode test
- When you've been an idiot and left a probe in the A jack when the meter is in voltage mode (assuming it's using sensing jacks - can't remember if this is the case)
- Over-load warning on ranges where an overload could cause damage

Other than those, I'd normally want the beeper off, so I'd agree with everyone asking for a middle option (preferably as a third setting in addition to the current two)
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on March 08, 2018, 11:24:22 am
Bluetooth and VA mode is still completely broken, even if you filter the invalid records.
It's also broken in the android app. It displays the same wrong readings.

The 391.2 mVA reading is the correct one.

I can confirm this, I see infrequent large scale data value excursion in VA mode. Reported.
Title: Re: EEVBlog 121GW Discussion thread
Post by: mtdoc on March 08, 2018, 12:13:06 pm
I personally think the beeper is necessary in the following circumstances:
- Continuity (which even uses the sound symbol!)
- Diode test
- When you've been an idiot and left a probe in the A jack when the meter is in voltage mode (assuming it's using sensing jacks - can't remember if this is the case)
- Over-load warning on ranges where an overload could cause damage

Other than those, I'd normally want the beeper off, so I'd agree with everyone asking for a middle option (preferably as a third setting in addition to the current two)

I agree. That seems like a no brainer.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Seppy on March 09, 2018, 02:27:22 pm
a) Nothing was "removed in editing". The entire original 23 hour video is still being processed by youtube and will eventually be available online. It seems that only the final 2 hours is currently available.

b) By the "edited video" I presume you mean the one "How to do Lifecycle Testing". I simply extracted some content from the stream to create a new video were I talked about general range switch testing as I thought it might be interesting to people as separate video.

c) There is a uCurrent x100 amplifier used in the jig across the switch contacts, that is not shown in the equations.

The 24 hour video was no longer listed when I checked, so yes I was referring to your how-to video.   

Quote
.. r=v/2300 and R=2740/((1/r)-1) . The second note stated the first column was V.    So for v=128,  R=2740/((2300/128)-1) = 152.5. 

I assume it's not as simple as it being off by 100X or 0.152 ohms,  seems way too low but maybe.     Looking at V=1272, R = 1.516 in this case and I think it was much higher.  Strange that the basics are not clear or just coded.



There is a 100x amplifier, that formula didn't show the uCurrent gain.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Seppy on March 09, 2018, 02:43:12 pm
Maybe someone can explain to me what the problem is:
2 different function generators tested, JDS6600 and FeelTech FY6600. Identical settings, identical results.

For example: 4kHz SQRT with 2Vpp. Measured ACV with the 121GW and as comparison a Fluke 28II (highres mode).

Range AUTO: 121GW selects 5V range, Fluke selects 6V range
121GW reads 1,37xxVac, Fluke reads 0,99xxVac

Manual range 5V 121GW, 6V Fluke 28II:
121GW reads 1,37xxVac, Fluke reads 0,99xxVac

Manual range 50V 121GW, 60V Fluke 28II:
121GW reads 0,95xVac, Fluke reads 0,94xxVac

Did you mean 2V peak to peak square wave, what did you mean by square root (SQRT)?
I reproduced the test and do not get your results. I get 1.0022 Vrms on a production meter for the above setup.

Did you signal generator have a DC offset, if so make sure that the 121GW isn't in DC + AC mode.
DC + AC mode for a 0 - 2V square wave results in approximately 1.4V, which is close to what you measured.

Title: Re: EEVBlog 121GW Discussion thread
Post by: Candid on March 09, 2018, 11:24:58 pm
Sorry, my mistake. square wave for sure.

Can you reproduce the following measurements?
2.0V peak to peak sine wave 4kHz, No DC offset, duty cycle 50%. Both meters in AC mode. Firmware 1.07 on my 121GW with serial number EEVblog 000084

Auto mode on both meters, Fluke in highres mode:
121GW selects 5V range, reads 1.1133Vac
Fluke 28II selects 6V range, reads 0.7031Vac

manual mode on both meters:
121GW 5V range, reads 1.1133Vac
Fluke 28II 6V range, 0.7032Vac

121GW 50V range, reads 0.659Vac (and it looses the frequency measurement and displays 0.00kHz)
Fluke 28II 60V range, reads 0.663Vac

See the attached pictures.
Title: Re: EEVBlog 121GW Discussion thread
Post by: fanOfeeDIY on March 12, 2018, 08:52:36 am
I uploaded video regarding roughly comparing Burden Voltage.

https://youtu.be/sSyZtqiWmvg (https://youtu.be/sSyZtqiWmvg)
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on March 12, 2018, 10:26:42 am
I uploaded video regarding roughly comparing Burden Voltage.

Quote
On your 121GW, you do have a fairly high resolution. In the Amps low range, I think its 10uA resolution which is what you have with the other meters. However, your burden voltage is to be VERY low. Maybe 200ish uv!! Try that and see what you think.? 

I posted the above comment on YT.   Looking in the manual, maybe it no longer works this but I'm pretty sure that the prototype did.

The 500mA range uses the Amps jack (and a x10 amplifier) unlike most meters. This gives a very low maximum burden voltage of 30mV/A, or 15mV for 500mA full scale.
Very few meters will be this low on the 500mA range.
With 50,000 count the resolution is 10uA.
Title: Re: EEVBlog 121GW Discussion thread
Post by: fanOfeeDIY on March 12, 2018, 11:15:47 am
I uploaded video regarding roughly comparing Burden Voltage.

Quote
On your 121GW, you do have a fairly high resolution. In the Amps low range, I think its 10uA resolution which is what you have with the other meters. However, your burden voltage is to be VERY low. Maybe 200ish uv!! Try that and see what you think.? 

I posted the above comment on YT.   Looking in the manual, maybe it no longer works this but I'm pretty sure that the prototype did.

The 500mA range uses the Amps jack (and a x10 amplifier) unlike most meters. This gives a very low maximum burden voltage of 30mV/A, or 15mV for 500mA full scale.
Very few meters will be this low on the 500mA range.
With 50,000 count the resolution is 10uA.
Thanks.   

I had DL'ed the manual when you made it available.  The one I have is 25th Nov. 17.   I see a mention of the 500mA mode on page 11. 

Quote
A and 500mA    11A/1000V DC/AC, IR 20kA HRC FAST + DIODE
and again on page 55
Quote
A/500mA current input fuse: 11A/1000V DC/AC, IR 20kA HRC FAST

The table on page 14 does not mention it.   
Quote
The following modes will use the x10 amplifier and may have additional off-set error that can be nulled out before measurement.

Maybe add something to page 32 where the current measurement is shown.   When I looked at the burden on the pre-production, is was pretty impressive.  From fanOfeeDIY's video, the manual may need a few small additions. 

Maybe you (Dave) would consider making a short video showing the meter's burden compared to a few others and how to use it properly.   

I am not quite following the discussion.  :'(
Especially "200ish uv!!" part.
Should I have used different range in my video?

Title: EEVBlog 121GW Discussion thread
Post by: fanOfeeDIY on March 12, 2018, 11:44:13 am
I am not quite following the discussion. 
Especially "200ish uv!!" part.
Should I have used different range in my video?

Do the same test with your 121GW except attach the leads from the A 500mA connector and the COM.   The 121GW will display the current with a resolution of 10uA just like the others you show.  However, now if you look at the burden voltage for the meter, I suspect you will see something around 200uV  rather then several mV as your video shows.   I use "ish" as close enough.   

I had modified a UNI-T UT61E which has a very high burden voltage, in an attempt to improve it.   There was only so much I could do in the area available and the way the board was laid out.  I think are real low current, the burden on this meter was lower than the 121GW but once I changed ranged, it was very clear just how good the 121GW was.   It's impressive.   Give it a try and see what happens.  Post your updates, text is good enough.

Ah, I completely understood now.

Let me take and upload a short video tonight as your advice with A/500mA connector.
I still have the setup on my desk.
Title: Re: EEVBlog 121GW Discussion thread
Post by: fanOfeeDIY on March 12, 2018, 09:31:45 pm
I am not quite following the discussion.  :'(
Especially "200ish uv!!" part.
Should I have used different range in my video?

Do the same test with your 121GW except attach the leads from the A 500mA connector and the COM.   The 121GW will display the current with a resolution of 10uA just like the others you show.  However, now if you look at the burden voltage for the meter, I suspect you will see something around 200uV  rather then several mV as your video shows.   I use "ish" as close enough.   

I had modified a UNI-T UT61E which has a very high burden voltage, in an attempt to improve it.   There was only so much I could do in the area available and the way the board was laid out.  I think are real low current, the burden on this meter was lower than the 121GW but once I changed ranged, it was very clear just how good the 121GW was.   It's impressive.   Give it a try and see what happens.  Post your updates, text is good enough.

Thank you for your valuable comment on both YouTube and here.
I uploaded another video.
https://youtu.be/ffP1Y0zp9KE
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on March 12, 2018, 09:50:59 pm
Maybe add something to page 32 where the current measurement is shown.   When I looked at the burden on the pre-production, is was pretty impressive.  From fanOfeeDIY's video, the manual may need a few small additions. 

Yep, the manual needs some updating.
The burden voltage may not be much better than, or on par with some other meters depending upon the range selected. It's a combination of what range uses the x10 amplifier and what shunt is used.
You could get the same excellent burden voltage on every range, but you'd need a effectively manual range switch positions with an optimised shunt for every range.
Very few meters will use the A jack for the 500mA range, so if your needs are on that range, it's going to be hard to beat.
Title: Re: EEVBlog 121GW Discussion thread
Post by: joeqsmith on March 12, 2018, 10:07:20 pm
Thank you for your valuable comment on both YouTube and here.
I uploaded another video.
Thank you for taking the time to run the test a second time. 
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on March 14, 2018, 09:50:39 am
V1.09 firmware https://www.eevblog.com/wp-content/uploads/2017/11/EEVBlog1_09.zip (https://www.eevblog.com/wp-content/uploads/2017/11/EEVBlog1_09.zip)
It fixes the issue with the VA mode Bluetooth connection sending garbage data.

Title: Re: EEVBlog 121GW Discussion thread
Post by: dcac on March 14, 2018, 11:31:06 pm
I am not quite following the discussion.  :'(
Especially "200ish uv!!" part.
Should I have used different range in my video?

Do the same test with your 121GW except attach the leads from the A 500mA connector and the COM.   The 121GW will display the current with a resolution of 10uA just like the others you show.  However, now if you look at the burden voltage for the meter, I suspect you will see something around 200uV  rather then several mV as your video shows.   I use "ish" as close enough.   

I had modified a UNI-T UT61E which has a very high burden voltage, in an attempt to improve it.   There was only so much I could do in the area available and the way the board was laid out.  I think are real low current, the burden on this meter was lower than the 121GW but once I changed ranged, it was very clear just how good the 121GW was.   It's impressive.   Give it a try and see what happens.  Post your updates, text is good enough.

Thank you for your valuable comment on both YouTube and here.
I uploaded another video.
https://youtu.be/ffP1Y0zp9KE

Is the 121GW current measurement really within spec. here, it seems to show something like 4.6000mA when using the mA/uA jack but using the 10A jack it shows about 4.23mA - seems quite a bit of to me.

Title: Re: EEVBlog 121GW Discussion thread
Post by: ChrisG on March 15, 2018, 07:04:03 am
The beeping beeper is a bit funny indeed now. When switched off it does not beep at all, whilst the beeper icon is showing still. So agree and concur with the others. Suggestion for the Manual: make clear that the bin file needs to be named EEVblog.bin exactly. When I used the EEVblog1.09.bin file name it did not work, waited for 5 minutes and then decided to abort.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Iagash on March 16, 2018, 03:54:40 am
V1.09 firmware https://www.eevblog.com/wp-content/uploads/2017/11/EEVBlog1_09.zip (https://www.eevblog.com/wp-content/uploads/2017/11/EEVBlog1_09.zip)
It fixes the issue with the VA mode Bluetooth connection sending garbage data.

Not really, the main display is correct now, but the upper display lost any connection to reality.

The corrupted data records are still there but less frequent.

 :palm:
Title: Re: EEVBlog 121GW Discussion thread
Post by: Iagash on March 16, 2018, 05:05:55 am
I'm sure they run some sort of regression testing before they release updates and that is partly why UEI's response is slow.

Well, then you are a lot more optimistic than me.

Then again, now that Dave has stepped into the role of running life cycle testing maybe he needs to expand into some sort of firmware quality role as well.

Well I'll attach my console tool for the 121gw.
You can use it via:
Code: [Select]
gatttool -b 88:6B:XX:XX:XX:XX --char-write-req -a 0x0009 -n 0300 --listen | ./121gw.pl

To log into a file for later examination use:
Code: [Select]
gatttool -b 88:6B:XX:XX:XX:XX --char-write-req -a 0x0009 -n 0300 --listen | ./121gw.pl 2>&1 | tee logfile.txt

To find the BT address use:
Code: [Select]
hcitool lescan
and press ctrl-C when it is found.

You just need a linux system with bluetooth installed. Anything like debian jessie or newer should do. The gatttool command is in the bluez package. Nothing else is required.


Maybe Dave should make a video about what a ringbuffer is, how to find out how much space is left and skip writing a record now and then if bluetooth is too slow instead of overwriting not yet sent data.

I guess UEI is clearly in need of one.
Title: Re: EEVBlog 121GW Discussion thread
Post by: 1anX on March 16, 2018, 08:32:22 am
V1.09 firmware https://www.eevblog.com/wp-content/uploads/2017/11/EEVBlog1_09.zip (https://www.eevblog.com/wp-content/uploads/2017/11/EEVBlog1_09.zip)
It fixes the issue with the VA mode Bluetooth connection sending garbage data.

Not really, the main display is correct now, but the upper display lost any connection to reality.

The corrupted data records are still there but less frequent.

 :palm:

Just when I think headway is being made in correcting and fixing this meter's faults, the reoccurring theme, which is a lack of testing yet again raises its head!

Like Joe said, its Dave's name/brand on the meter so he must assume ultimate responsibility as the marketer and seller of this device to ensure it actually works as specified!
Title: Re: EEVBlog 121GW Discussion thread
Post by: 1anX on March 16, 2018, 11:45:02 am
It seems 1.09 was a regression of other functionality in the VA mode.
The link has been removed.

Not sure what you mean by this? Can you please explain in a little detail just what testing is done and how you are releasing the updates!

I looked up regression testing as opposed to retesting fixed faults and found this defined as below...

"Retesting is done to make sure that the tests cases which failed in last execution are passing after the defects against those failures are fixed. Regression testing is not carried out on specific defect fixes. ... In Regression testing, you can include the test cases which passed earlier."


What process is UEi and Dave following for firmware releases?

Thanks in advance for any info you may wish to post, I find this educational and am learning how the development for this meter is evolving.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Seppy on March 16, 2018, 12:06:28 pm
It appears that the firmware may not be a regression, I believe I just found a new error in AC mode and thought it was a regression.

V1.09 firmware https://www.eevblog.com/wp-content/uploads/2017/11/EEVBlog1_09.zip (https://www.eevblog.com/wp-content/uploads/2017/11/EEVBlog1_09.zip)
It fixes the issue with the VA mode Bluetooth connection sending garbage data.

Not really, the main display is correct now, but the upper display lost any connection to reality.

The corrupted data records are still there but less frequent.

 :palm:


Can you confirm your setup was in DC mode? What were the conditions which resulted in the incorrect values of the secondary display on the 121GW?

Old post about this was removed as it seems it was not a regression and instead a different error.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Iagash on March 16, 2018, 12:54:48 pm

Can you confirm your setup was in DC mode? What were the conditions which resulted in the incorrect values of the secondary display on the 121GW?

Old post about this was removed as it seems it was not a regression and instead a different error.

I used DC mode, 400mA, 3.7V, 1.42VA. Both displays on the meter itself are perfect.

The display via bluetooth on the secondary display is 2.9V and 255.86A, the main display is fine.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Seppy on March 16, 2018, 01:29:08 pm

Can you confirm your setup was in DC mode? What were the conditions which resulted in the incorrect values of the secondary display on the 121GW?

Old post about this was removed as it seems it was not a regression and instead a different error.

I used DC mode, 400mA, 3.7V, 1.42VA. Both displays on the meter itself are perfect.

The display via bluetooth on the secondary display is 2.9V and 255.86A, the main display is fine.

Are you on windows or Android, which version of the app?
Title: Re: EEVBlog 121GW Discussion thread
Post by: Iagash on March 16, 2018, 01:34:45 pm
Are you on windows or Android, which version of the app?

I tried Android Version 0 eevblog.x121gw, but my perl script displays the same values.

It doesn't matter, fix the BT transmission with a correct buffering implementation.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Seppy on March 16, 2018, 02:46:55 pm
Are you on windows or Android, which version of the app?

I tried Android Version 0 eevblog.x121gw, but my perl script displays the same values.

It doesn't matter, fix the BT transmission with a correct buffering implementation.

I understand the Perl script might be receiving the wrong thing too. Just to be thorough can you check if the updated android app resolves your issue.
Curiously the android app store might not have received the latest updates... Checking into this now... Ok it should be version 1 now :)
Title: Re: EEVBlog 121GW Discussion thread
Post by: Iagash on March 16, 2018, 10:53:31 pm
I understand the Perl script might be receiving the wrong thing too. Just to be thorough can you check if the updated android app resolves your issue.
Curiously the android app store might not have received the latest updates... Checking into this now... Ok it should be version 1 now :)

Thanks.

I tried with version 1, it's still as broken as version 0.

Could you push your changes to github?

I'm more interested in receiving the data on my desktop, I use the phone just for checking.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Iagash on March 16, 2018, 11:53:32 pm
The errors on the main display are also still there if you leave it running a bit longer:

Quote
1521202937.913 2017-08 00042    Power DC (VA)  1409.7 mVA       DCA  255.34
1521202938.183 2017-08 00042    Power DC (VA)  140.97 VA        DCA  255.34
1521202938.858 2017-08 00042    Power DC (VA)  1409.7 mVA       DCA  255.34
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on March 17, 2018, 12:37:24 am
What process is UEi and Dave following for firmware releases?

I do not know what procedures or processes UEi use.
As for this firmware release, UEi said they fixed the issues with the VA mode data corruption on Bluetooth, so we checked that and it seemed to be fixed, so I released the firmware on here so other could try it.
David has a setup that is sniffing the microcontroller UART data and comparing with received Bluetooth data. We could see the data corruption clearly before the fix and after the fix it's gone. It was reasonable to conclude they had fixed it, so pushed it out for others to confirm. We didn't test anything else on this release.

At this point we are basically using the current user base as a testing platform to find and confirm bug fixes. There is nothing better than giving it to a few hundred people and getting feedback. Would current owner prefer we not make interim firmware releases available for testing?
Title: Re: EEVBlog 121GW Discussion thread
Post by: Iagash on March 17, 2018, 01:03:48 am
At this point we are basically using the current user base as a testing platform to find and confirm bug fixes. There is nothing better than giving it to a few hundred people and getting feedback.

This is fine, but please "fix" things and don't "cover up".

The bluetooth transmission is broken by design and by implementation.

Would current owner prefer we not make interim firmware releases available for testing?

I'm fine with testing, no problem.

But the 1.07 -> 1.09 is not a fix, it's just trying to cover up above mentioned errors a bit better.

Start with fixing the missing CRC. Then errors can be detected reliably and automatically and one can trust the data received is what the firmware wanted to send.
Title: Re: EEVBlog 121GW Discussion thread
Post by: 1anX on March 17, 2018, 09:06:04 am
What process is UEi and Dave following for firmware releases?
At this point we are basically using the current user base as a testing platform to find and confirm bug fixes. There is nothing better than giving it to a few hundred people and getting feedback. Would current owner prefer we not make interim firmware releases available for testing?

Thanks Dave!

My concern was that in your previous post you stated that the new firmware release fixed the BT data corruption issues. You maybe could have said please test this new release which addresses the BT data corruption issue and provide feedback if any issue remains.

I know it seems pedantic but when you claim that the issue is fixed, we actually believe the issue is fixed!

I worked in a metrology lab for a few years and that required me to be pedantic. Near enough is not good enough  :)
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on March 17, 2018, 09:31:29 am
My concern was that in your previous post you stated that the new firmware release fixed the BT data corruption issues. You maybe could have said please test this new release which addresses the BT data corruption issue and provide feedback if any issue remains.

Yes, I should have said that, sorry.
From our end it did look like the data corruption UART issue we reported had been fixed, and that seems to be the case.
I know some people are still reporting bluetooth data corruption issues, and this seems to be a different issue than the one we had UEi adress, which was corrupted data output from the UART in the micro.
Please take every release at this stage to mean "we believe it's fixed, please test it and let us know if you find any issues".
Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on March 17, 2018, 01:29:06 pm
At this point we are basically using the current user base as a testing platform to find and confirm bug fixes. There is nothing better than giving it to a few hundred people and getting feedback.
This is understandable - and very effective - but there will be some who will get their nose out of joint because everything isn't perfect ... including the software revisions.  To those I say this: When a car maker designs and builds a new car, they don't just dump the first models straight from the factory to the showroom.  It goes through a proving ground where issues are identified and dealt with.  For the 121GW - we are that proving ground and we are still in the stage of finding and fixing issues.

From our end it did look like the data corruption UART issue we reported had been fixed, and that seems to be the case.
I know some people are still reporting bluetooth data corruption issues, and this seems to be a different issue than the one we had UEi adress, which was corrupted data output from the UART in the micro.
This is a good example where different problems can have similar looking symptoms - and that the fixing of one problem may not result in a total cure.  For a complete solution, each and every problem needs to be individually identified and addressed.  Where it is stated that one particular problem has been fixed, don't immediately assume the symptoms you have observed should go away and that if they don't, that you are being misled.

Quote
Please take every release at this stage to mean "we believe it's fixed, please test it and let us know if you find any issues".
This.
Title: Re: EEVBlog 121GW Discussion thread
Post by: joeqsmith on March 17, 2018, 02:10:22 pm
At this point we are basically using the current user base as a testing platform to find and confirm bug fixes. There is nothing better than giving it to a few hundred people and getting feedback.
This is understandable - and very effective - but there will be some who will get their nose out of joint because everything isn't perfect ... including the software revisions.  To those I say this: When a car maker designs and builds a new car, they don't just dump the first models straight from the factory to the showroom.  It goes through a proving ground where issues are identified and dealt with.  For the 121GW - we are that proving ground and we are still in the stage of finding and fixing issues.
It was not clear to me that people purchasing the meter were expected to be Beta tester's until I had heard Dave mention it during an AmpHour.   I'm sure he must have stated this upfront and I just missed it.   As long as it was made clear, I don't see a problem.  On the other hand, if it wasn't and people were trusting that Dave would not allow it to be sold as a Beta, then maybe that's a problem.  Seems like most in the USA are still waiting, so no concerns other than not meeting their scheduled dates. 
Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on March 17, 2018, 02:56:42 pm
I must admit that I cannot recall Dave making such a statement (I don't listen to many Amphour episodes) - but it was just my natural expectation for a brand new product having non trivial features.

To me, it is essentially the same as when a new operating system is released.  However much it has been tested and stressed, there are always some issues that show up when a broader user base gets involved.

For the 121GW, I saw this as normal.


(IMO, Dave's best move was getting that micro SD card slot included.  Without that, firmware updates would have been a lot harder for some people.)
Title: Re: EEVBlog 121GW Discussion thread
Post by: dcac on March 18, 2018, 02:07:34 am
I don’t think anyone is surprised that there was issues still needing to be fixed - but for me beta-testing is a contract you “sign-up” for and really not anything I would “buy into”. Dave never ever used a term like beta-testing in his promotion of the 121GW and I really do not envy those backers who got semi-hassled into it. Also it’s (not) funny with those who are not backers at all having much opinions on what to expect and what not to expect. I’m a JB Goode backer my self but are no longer particularly keen on getting my 121GW delivered, if I now say it’s because I know there will still be issues needing to be fixed - I’m sure the none-backers will tell me - to not be so pessimistic.
Title: Re: EEVBlog 121GW Discussion thread
Post by: 1anX on March 18, 2018, 09:23:11 am
A one sentence summary would be that the 121GW meter was a good idea poorly implemented!

Hindsight is a wonderful thing, but maybe if Dave ponied up and backed his own idea and design instead of a freebie UEi deal, it may have actually been developed and tested before being released to backers to buy?

The potential for getting a useful meter, (I'm Johnny Be Goode backer) is still high, but the way it has been handled with bugs and switch problems has certainly knocked the gloss of acquiring this meter for me!
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on March 19, 2018, 11:02:16 am
I am not sure why he chose to use the open forums for discussions and bug reporting versus the locked down kick start area.  Maybe he has more control over the content here. 

Kickstarter comments sucks as a place to hold discussion from a technical and usability point of view, but yes, I could have done that and "kept it quiet", but this forum is just a better place to do it, so here it is. If I wanted to "have control" then this whole thread wouldn't even exist, let alone be set as sticky.
But maybe I should have kept it on Kickstarter as those people are the ones vested in it?  :-//
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on March 19, 2018, 11:13:37 am
At this point we are basically using the current user base as a testing platform to find and confirm bug fixes. There is nothing better than giving it to a few hundred people and getting feedback.
This is understandable - and very effective - but there will be some who will get their nose out of joint because everything isn't perfect ... including the software revisions.  To those I say this: When a car maker designs and builds a new car, they don't just dump the first models straight from the factory to the showroom.  It goes through a proving ground where issues are identified and dealt with.  For the 121GW - we are that proving ground and we are still in the stage of finding and fixing issues.

We didn't want that to be the case of course, but we've been essentially forced into this situation with the unexpected problems that have popped up.
And by "forced into" I mean it's basically the best way forward at this point for all involved.
The best way to get issues found is by having as many people as possible use the meter and provide feedback as possible. Given that we have like 200 or something meters out there in the field now, it just makes sense to at least ask these owners to try new firmware and continue to provide feedback before we ship 2000 of them. They don't have to of course, they can stick with the firmware they have got.
But ultimately any new firmware on a reasonably complex product like this is going to have issues that will take time to sort out.

BTW, David in his testing has found a couple of more unreported issues that are currently being looked into, hence more delays unfortunately.
Title: Re: EEVBlog 121GW Discussion thread
Post by: The Soulman on March 19, 2018, 11:24:58 am
At this point we are basically using the current user base as a testing platform to find and confirm bug fixes. There is nothing better than giving it to a few hundred people and getting feedback.
This is understandable - and very effective - but there will be some who will get their nose out of joint because everything isn't perfect ... including the software revisions.  To those I say this: When a car maker designs and builds a new car, they don't just dump the first models straight from the factory to the showroom.  It goes through a proving ground where issues are identified and dealt with.  For the 121GW - we are that proving ground and we are still in the stage of finding and fixing issues.

We didn't want that to be the case of course, but we've been essentially forced into this situation with the unexpected problems that have popped up.
And by "forced into" I mean it's basically the best way forward at this point for all involved.
The best way to get issues found is by having as many people as possible use the meter and provide feedback as possible. Given that we have like 200 or something meters out there in the field now, it just makes sense to at least ask these owners to try new firmware and continue to provide feedback before we ship 2000 of them. They don't have to of course, they can stick with the firmware they have got.
But ultimately any new firmware on a reasonably complex product like this is going to have issues that will take time to sort out.

BTW, David in his testing has found a couple of more unreported issues that are currently being looked into, hence more delays unfortunately.

Those 2000 get the updated hardware (switch..) right?
What about the meters stuck at the harbor, are these unstuck yet?
What about selling these to "qualified" (those that are aware of what they are getting themselves into) beta testers?
Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on March 19, 2018, 08:18:09 pm
At this point we are basically using the current user base as a testing platform to find and confirm bug fixes. There is nothing better than giving it to a few hundred people and getting feedback.
This is understandable - and very effective - but there will be some who will get their nose out of joint because everything isn't perfect ... including the software revisions.  To those I say this: When a car maker designs and builds a new car, they don't just dump the first models straight from the factory to the showroom.  It goes through a proving ground where issues are identified and dealt with.  For the 121GW - we are that proving ground and we are still in the stage of finding and fixing issues.

We didn't want that to be the case of course, but we've been essentially forced into this situation with the unexpected problems that have popped up.
And by "forced into" I mean it's basically the best way forward at this point for all involved.

I have no doubt at all you didn't want to have to be in this position - but it seems fairly clear that the testing phase has been poorly executed.  Where that fell short will be a lesson for future benefit.  For now, the best effort is in sorting it out.

I will say that if the 121GW had hit the deck with no significant issues, I would have been truly impressed - but the number of issues detailed so far has been a bit of a surprise.  What I expected to be a bit of "fine tuning" has turned into a significant exercise.  I think Dave would have had a similar expectation.


There is no question, however, that the way forward has been defined by the situation.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on March 19, 2018, 08:55:51 pm
A one sentence summary would be that the 121GW meter was a good idea poorly implemented!
I understand where you are coming from, but I would call that a bit harsh.  I would call that a "consumer" comment, not an "engineer" one.

Quote
Hindsight is a wonderful thing, but maybe if Dave ponied up and backed his own idea and design instead of a freebie UEi deal, it may have actually been developed and tested before being released to backers to buy?
There are a lot of factors in producing any item and I sincerely doubt Dave would have been able to bring this product to life without UEI's contribution.  Certainly, there has been an issue with the testing and that is the only criticism I have - but Dave probably didn't do himself any favours by having the development so highly visible.  The interest and yearning from so many members no doubt added a lot of pressure to get the product out.

Quote
The potential for getting a useful meter, (I'm Johnny Be Goode backer) is still high, but the way it has been handled with bugs and switch problems has certainly knocked the gloss of acquiring this meter for me!
I am quite the opposite.  Having seen the effort being put in, I am becoming more engaged.  The gloss is increasing!
Title: Re: EEVBlog 121GW Discussion thread
Post by: IanB on March 19, 2018, 09:08:41 pm
I will say that if the 121GW had hit the deck with no significant issues, I would have been truly impressed - but the number of issues detailed so far has been a bit of a surprise.  What I expected to be a bit of "fine tuning" has turned into a significant exercise.  I think Dave would have had a similar expectation.

This is, IHMO, a sign of the times and an indication of the state of business and commerce today. Costs are being driven down, work is being outsourced, complicated tasks are being assigned to the young and inexperienced.

As far as the 121GW is concerned, I bet the hardware has far fewer issues than the software. It's because software design is not recognized as challenging problem requiring deep expertise, and software then gets written by "coders" instead of engineers. The word "coding" should be removed from the dictionary.

I am sure we have all experienced web sites and phone apps that are simply buggy, broken and unpredictable in use. It's all symptomatic of the same general trend.

Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on March 19, 2018, 09:31:09 pm
As far as the 121GW is concerned, I bet the hardware has far fewer issues than the software. It's because software design is not recognized as challenging problem requiring deep expertise, and software then gets written by "coders" instead of engineers. The word "coding" should be removed from the dictionary.

The 121GW has an extra layer complexity in the chipset, which has crazy amounts of configurability and modes etc. UEi had to recently go to Hycontech to ask their advice on some things for example.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on March 19, 2018, 09:32:58 pm
Dave probably didn't do himself any favours by having the development so highly visible. 

Yep, I'm not very smart  :palm:
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on March 19, 2018, 09:34:51 pm
Those 2000 get the updated hardware (switch..) right?
[\quote]

Yes.

Quote
What about the meters stuck at the harbor, are these unstuck yet?

Yep, all finally unstuck.

Quote
What about selling these to "qualified" (those that are aware of what they are getting themselves into) beta testers?

I'd rather not, we already have enough keen people out there testing I think.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on March 19, 2018, 10:53:53 pm
Dave probably didn't do himself any favours by having the development so highly visible. 

Yep, I'm not very smart  :palm:

I wouldn't say that.  Doing the 121GW was an exciting project.  Sharing it was mandatory!

What I will say is that, having been a member of the 121GW Voyeurs Club, I have a much greater "connection" to the 121GW than I do to any other meter ... and I haven't even ordered one yet!

I don't have a big problem with the issues at hand - just as long as they are addressed.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on March 19, 2018, 11:07:36 pm
Sure.  Play that card if you must, but even if I did have a 121GW in front of me right now, my answer would be the same.

I have means to make measurement with other gear I have.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Iagash on March 19, 2018, 11:26:50 pm
Well. I don't have an issue with the issues too. But I have a bit of an issue on how the issues are addressed.

Dave and Seppy know about the invalid bluetooth records. They worked around them in their app. But instead of asking UEI to include some checksum or CRC in the records, they decided on guessing if the data could be valid and try to suppress records in the application, that look wrong.

If you use your phone for logging and send yourself the logfile, you can see that also their app fails at guessing always correctly. You mostly don't see it on the phone display, as you don't look constantly at it and miss the occasional wrong value, but it's in the log of the app.

I can understand, that finding the cause of the errors might be hard, but adding a CRC to the records is a no-brainer and around 30 lines of code.

That's the part I don't understand.
Title: Re: EEVBlog 121GW Discussion thread
Post by: FrankBuss on March 19, 2018, 11:55:41 pm
At this point we are basically using the current user base as a testing platform to find and confirm bug fixes. There is nothing better than giving it to a few hundred people and getting feedback.

This is fine, but please "fix" things and don't "cover up".

The bluetooth transmission is broken by design and by implementation.
  • There is no data integrity, aka. CRC or something on records (design error)
  • The ASCII decimal/hex coding wastes more then 2/3 of the already scarce bluetooth bandwidth (design error)
  • You have to check every single byte received for plausibility (and you'll fail in a lot of cases) (implementation error)
  • If you look at the errors in the data it's clear that some buffer in the firmware get's overwritten (implementation error)

Would current owner prefer we not make interim firmware releases available for testing?

I'm fine with testing, no problem.

But the 1.07 -> 1.09 is not a fix, it's just trying to cover up above mentioned errors a bit better.

Start with fixing the missing CRC. Then errors can be detected reliably and automatically and one can trust the data received is what the firmware wanted to send.

No need to implement CRC, because BLE has this already integrated on the lower levels and automatically resends packets, if they are wrong, so no need to implement it on the data layer. Usually you can be sure that the transmitted data is right, so it must be another problem.

I personally tested a Blue Gecko chip from Silicon Labs with BLE and at the application level only the packet rate drops when I increase the distance. Here are some numbers where the device was sending 20 byte packets with max speed, which I recorded with a Python script :

Code: [Select]

measuring in 1 m distance:

number of packets: 348697
transfer time: 255 s
lost packets: 0
average transfer rate: 27310 bytes per second
max delay between two packets: 79.6 ms
min delay between two packets: 0.0 ms

measuring in 7m distance, with 2 walls in between:

number of packets: 265549
transfer time: 331 s
lost packets: 0
average transfer rate: 16044 bytes per second
max delay between two packets: 284.1 ms
min delay between two packets: 0.0 ms

This was with a standard BLE dongle on a PC, which identifies in Linux as this with lsusb:

Code: [Select]
Bus 001 Device 012: ID 0a12:0001 Cambridge Silicon Radio, Ltd Bluetooth Dongle (HCI mode)

I implemented the nRF UART protocol on the BLE chip for easier testing, as described here:

https://www.silabs.com/community/wireless/bluetooth/forum.topic.html/how_to_implementuar-ovZ7 (https://www.silabs.com/community/wireless/bluetooth/forum.topic.html/how_to_implementuar-ovZ7)

Because I really don't like all the complexity of BLE, give me just a reliable UART link, which works for me now. Maybe UEI should hire me to fix their bluetooth implementation :)

Here is the Python script which received the data on the PC:

Code: [Select]
import struct
from bluepy.btle import *

 # callback class
class MyDelegate(DefaultDelegate):
    def __init__(self):
        DefaultDelegate.__init__(self)

    def handleNotification(self, cHandle, data):
        print(data)

 # connect to device
per = Peripheral("00:0B:57:1D:B3:93", "public")

try:
    # set callback for notifications
    per.setDelegate(MyDelegate())

    # enable notification
    setup_data = b"\x01\x00"
    notify = per.getCharacteristics(uuid='6e400003-b5a3-f393-e0a9-e50e24dcca9e')[0]
    notify_handle = notify.getHandle() + 1
    per.writeCharacteristic(notify_handle, setup_data, withResponse=True)
   
    # send test string
    c = per.getCharacteristics(uuid='6e400002-b5a3-f393-e0a9-e50e24dcca9e')[0]
    c.write("Hello Gecko")
   
    # wait for answer
    while True:
        if per.waitForNotifications(1.0):
            continue
finally:
    per.disconnect()

And here is the Python script which evaluated the received data to create the statistics:

Code: [Select]
#!/usr/bin/python

import sys

filename = sys.argv[1]

 # statistic variables
count = 0
lastPacketNumber = 0
lastTimestamp = 0
deltaSum = 0
maxDelta = 0
minDelta = 1e9
packetsLost = 0
absoluteTimestamp = 0

 # read file and calculate statistics
with open(filename, "r") as ins:
    for line in ins:
        values = line.split(";")
        packetNumber = int(values[0])
        timestamp = int(values[1])
        delta = timestamp - lastTimestamp
        if count > 0:
            if timestamp < lastTimestamp:
                delta = 32768 - lastTimestamp + timestamp
            if delta > maxDelta:
                maxDelta = delta
            if delta < minDelta:
                minDelta = delta
            absoluteTimestamp = absoluteTimestamp + delta
            if packetNumber - lastPacketNumber > 1:
                packetsLost = packetsLost + packetNumber - lastPacketNumber - 1
        lastPacketNumber = packetNumber
        lastTimestamp = timestamp
        count = count + 1

 # format milliseconds with suffix and one digit after the comma
def formatMs(ms):
    return "{:.1f} ms".format(ms)

 # convert ticks to seconds   
def ticksToS(tick):
    return float(tick) / 32768.0

 # convert ticks to miliiseconds
def ticksToMs(tick):
    return ticksToS(tick) * 1000.0

 # calculate some more statistics
transferTimeInSeconds = ticksToS(absoluteTimestamp)
bytesTransfered = count * 20
bytesPerSecond = float(bytesTransfered) / transferTimeInSeconds

 # show result
print("number of packets: %d" % (count))
print("transfer time: %d s" % (int(transferTimeInSeconds)))
print("lost packets: %d" % (packetsLost))
print("average transfer rate: %d bytes per second" % (int(bytesPerSecond)))
print("max delay between two packets: " + formatMs(ticksToMs(maxDelta)))
print("min delay between two packets: " + formatMs(ticksToMs(minDelta)))
Title: Re: EEVBlog 121GW Discussion thread
Post by: Iagash on March 20, 2018, 01:15:09 am
No need to implement CRC, because BLE has this already integrated on the lower levels and automatically resends packets, if they are wrong, so no need to implement it on the data layer. Usually you can be sure that the transmitted data is right, so it must be another problem.

Yes I know. I checked the BLE spec.

The problem is with the firmware communicating with the BLE-module and the guesswork seems to be in the App since last August. So they seem to know since some time.
Title: Re: EEVBlog 121GW Discussion thread
Post by: FrankBuss on March 20, 2018, 02:52:22 am
No need to implement CRC, because BLE has this already integrated on the lower levels and automatically resends packets, if they are wrong, so no need to implement it on the data layer. Usually you can be sure that the transmitted data is right, so it must be another problem.

Yes I know. I checked the BLE spec.

The problem is with the firmware communicating with the BLE-module and the guesswork seems to be in the App since last August. So they seem to know since some time.

Ok, but why did you write that the protocol is broken without some sort of data integrity like CRC? Even industry standard protocols like SCPI (which would be nice to have in the multimeter) don't have integrated checksums, but it is implemented in the lower levels as TCP/IP (don't know if GPIB has a checksum).
Title: Re: EEVBlog 121GW Discussion thread
Post by: Iagash on March 20, 2018, 03:01:41 am
Ok, but why did you write that the protocol is broken without some sort of data integrity like CRC? Even industry standard protocols like SCPI (which would be nice to have in the multimeter) don't have integrated checksums, but it is implemented in the lower levels as TCP/IP (don't know if GPIB has a checksum).

Since the serial communication between the BLE module and the CPU is not protected and obviously unreliable.
I guess it's hard to impossible to add protection to the BLE-module, so just make it end-to-end.

It's cheap and easy and you're set.
Title: Re: EEVBlog 121GW Discussion thread
Post by: FrankBuss on March 20, 2018, 07:50:45 am
Since the serial communication between the BLE module and the CPU is not protected and obviously unreliable.
I guess it's hard to impossible to add protection to the BLE-module, so just make it end-to-end.

It's cheap and easy and you're set.

This would be a bad patch, and if it is a problem in the firmware before the checksum is calculated, it wouldn't even help. But Dave wrote that one data corruption UART issue was fixed. Would be better to find all issues instead of trying to program workarounds. A few cm PCB trace UART with the typical baud rate that these chips uses, can't have transfer errors. But there can be interesting problems, if you don't set the interrupt priorities right, if you receive data over UART, or if you don't implement flow control right, if the BLE module needs this, like RTS/CTS or XON/XOFF.
Title: Re: EEVBlog 121GW Discussion thread
Post by: 1anX on March 20, 2018, 08:06:25 am
A one sentence summary would be that the 121GW meter was a good idea poorly implemented!
I understand where you are coming from, but I would call that a bit harsh.  I would call that a "consumer" comment, not an "engineer" one.

I would call my comment accurate!

The concept for this meter has a lot of merit and those of us that have placed our order understand what the specification will provide us with as users. Then to have the "production meter" released to backers with an out of spec switch that suffers from intermittent contact is pretty much unacceptable in 2018. Even the cheapest of multimeters have reliable switches and the 121GW is not a cheap meter.

The implementation of the meter with a chipset that both Daves and UEi combined dont understand fully was risky. It was risky for the users as its their money that could have been spent on a comparable reliable meter with a fully functioning switch and mature firmware.

Finally as you, (Brumby) like car and car manufacturing metaphors, here is one to consider. Thank god UEi and the 2 Daves dont use the "lets get everyone involved to test it in the real world" concept for developing and fixing the bugs in self driving cars for our public roads  :)

Having said all of the above and meaning it, I would also like to add that I am confident that eventually the meter will evolve into and match its concept. It was and is simply a "poor implementation", lets face it, the current meter is nothing more than a prototype.
 
Title: Re: EEVBlog 121GW Discussion thread
Post by: Iagash on March 20, 2018, 09:13:16 am
This would be a bad patch, and if it is a problem in the firmware before the checksum is calculated, it wouldn't even help.

But Dave wrote that one data corruption UART issue was fixed. Would be better to find all issues instead of trying to program workarounds.

Well, yes, you're right.

But considering the bug is there and known since last August, how do you calculate the chances that they'll find it, fix it and get it right?

The CRC is one or two man hours at UEI and one for Seppy in the app, that's worth less than two meters and you don't need to guess the data.
Title: Re: EEVBlog 121GW Discussion thread
Post by: glarsson on March 20, 2018, 10:21:06 am
I would prefer that the bug is fixed (and get all data points) rather than just made the corruption detectable with the help of CRC (and lose data points).
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on March 20, 2018, 12:14:12 pm
No need to implement CRC, because BLE has this already integrated on the lower levels and automatically resends packets, if they are wrong, so no need to implement it on the data layer. Usually you can be sure that the transmitted data is right, so it must be another problem.

Yes I know. I checked the BLE spec.

The problem is with the firmware communicating with the BLE-module and the guesswork seems to be in the App since last August. So they seem to know since some time.

The firmware and packet DOES have a XOR based checksum at the end.
Our software does multiple things to check for bad packets, but if a packet is not received in full for whatever bluetoothy reason, it might be hard to recover from that unless you do lots of stuff. David's app for example using a voting system among other things to handle non-fully received packets.
We are looking into this improving the packet protocol.
Title: Re: EEVBlog 121GW Discussion thread
Post by: nidlaX on March 20, 2018, 12:17:53 pm
No need to implement CRC, because BLE has this already integrated on the lower levels and automatically resends packets, if they are wrong, so no need to implement it on the data layer. Usually you can be sure that the transmitted data is right, so it must be another problem.

Yes I know. I checked the BLE spec.

The problem is with the firmware communicating with the BLE-module and the guesswork seems to be in the App since last August. So they seem to know since some time.

The firmware and packet DOES have a XOR based checksum at the end.
Our software does multiple things to check for bad packets, but if a packet is not received in full for whatever bluetoothy reason, it might be hard to recover from that unless you do lots of stuff. David's app for example using a voting system among other things to handle non-fully received packets.
We are looking into this improving the packet protocol.
It would be useful if the user could receive some feedback regarding incomplete / lost packets in the app.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Iagash on March 20, 2018, 09:12:38 pm
The firmware and packet DOES have a XOR based checksum at the end.
Thanks!

But I guess you won't tell me how it is calculated or why it doesn't seem to be used in your app. At least I can't find it.

What I find concerning data validation is this:
Code: [Select]
static bool is_valid(string input) {
       if (input.Length != 52)
                 return false;
       foreach (var c in input)             {
              if (!(Char.IsDigit(c) || Char.IsLetter(c)))
                     return false;
      }
      return true;
}
David's app for example using a voting system among other things to handle non-fully received packets.

Yeah, the data sometimes looks like the result of some democratic process.  :-DD

We are looking into this improving the packet protocol.

Thanks, I'm very much looking forward to this.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on March 20, 2018, 10:35:42 pm
But I guess you won't tell me how it is calculated or why it doesn't seem to be used in your app. At least I can't find it.

Not yet, because there is a chance it might change soon.
As for use in the app, only David can answer that.
The github code is not up to date either.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on March 20, 2018, 10:45:04 pm
The implementation of the meter with a chipset that both Daves and UEi combined dont understand fully was risky. It was risky for the users as its their money that could have been spent on a comparable reliable meter with a fully functioning switch and mature firmware.

Even the big names like Keysight, Fluke, Gossen, Extech etc have all released meters that are less than perfect and have had a range of issues from hardware to software, lost calibration data in updates, bricking, to safety. If you've been watching my videos for a long time you'd know that. One of them almost killed or injured me due to a design flaw. These were all "reliable" released meters from huge reputable names.
I was just talking to one of them the other day commenting on the issues we've unfortunately been having, and they laughed and said they have had much more embarrassing problems in released products. Shit happens.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Elasia on March 21, 2018, 06:17:47 am
The implementation of the meter with a chipset that both Daves and UEi combined dont understand fully was risky. It was risky for the users as its their money that could have been spent on a comparable reliable meter with a fully functioning switch and mature firmware.

Even the big names like Keysight, Fluke, Gossen, Extech etc have all released meters that are less than perfect and have had a range of issues from hardware to software, lost calibration data in updates, bricking, to safety. If you've been watching my videos for a long time you'd know that. One of them almost killed or injured me due to a design flaw. These were all "reliable" released meters from huge reputable names.
I was just talking to one of them the other day commenting on the issues we've unfortunately been having, and they laughed and said they have had much more embarrassing problems in released products. Shit happens.


The first microcontroller bootloader I made eons ago had a nasty flaw of bricking the chip due to brown outs causing code execution jumping into the bootloader code to erase the device!  Oppps

Wasnt that hard to fix with the addition of a reset chip and also by keying the erase code to needing unlock values not stored in the device itself but still... talk about egg on face!
Title: Re: EEVBlog 121GW Discussion thread
Post by: 1anX on March 21, 2018, 08:09:07 am
The implementation of the meter with a chipset that both Daves and UEi combined dont understand fully was risky. It was risky for the users as its their money that could have been spent on a comparable reliable meter with a fully functioning switch and mature firmware.

Even the big names like Keysight, Fluke, Gossen, Extech etc have all released meters that are less than perfect and have had a range of issues from hardware to software, lost calibration data in updates, bricking, to safety. If you've been watching my videos for a long time you'd know that. One of them almost killed or injured me due to a design flaw. These were all "reliable" released meters from huge reputable names.
I was just talking to one of them the other day commenting on the issues we've unfortunately been having, and they laughed and said they have had much more embarrassing problems in released products. Shit happens.

Well after criticizing the 121 GW for faulty switches and patches that were apparently poorly tested and then released as "production quality" I had an interesting purchase yesterday.

I purchased 3 Garmin 55 Dash Cams ($240ea) from Harvey Norman. Got home attached my power supply to the cam's charger and went thru setup and testing them. Cut a long story short, only 2 out of the 3 worked correctly. Two of these brand new units would not hold their setup data and would not write it to memory. This meant that every time the cam would power up, 20 or so button presses would be needed to get it to operate.

They will all be returned to HN today for a refund!

Garmin released a device that obviously was untested before being shipped out to sell and looking on a garmin forum it seems that the setup data failure is pretty widespread across the world. The Garmin 55 is an evolved product not a new design, so as you say Dave, shit happens and point taken!

Update!
The guy at HN this morning arranging the refund told me that he is on his 3rd iPhone X, as the previous 2 had charging and battery problems, he now wants it replaced with the iPhone Plus!
Title: Re: EEVBlog 121GW Discussion thread
Post by: imidis on March 21, 2018, 08:38:02 am
I don't have a 121GW or own one. However, many large corporations put out bug ridden and poorly built items. I think the big difference between them and Dave, is Dave cares. Instead of brushing things under the rug, ignoring or hiding them, avoiding any responsibility like so many companies do.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Elasia on March 21, 2018, 09:15:10 am
I don't have a 121GW or own one. However, many large corporations put out bug ridden and poorly built items. I think the big difference between them and Dave, is Dave cares. Instead of brushing things under the rug, ignoring or hiding them, avoiding any responsibility like so many companies do.

Not just large... you got a ton of hacks out there too due to companies just flat out either not understanding risk control around software or even ones that do and just dont give 2 cents... the medical device land is just littered with them and is absurd.  A lot of sectors could learn a thing or two from the avionics industry... probably the best group to have their shit together

I've mostly used agilent portable dmms but i think my next one will be a 121GW if there is a 2nd gen.. i do like the idea of it but late to the party this round
Title: Re: EEVBlog 121GW Discussion thread
Post by: lukasz.kostka on March 22, 2018, 01:23:29 am
Hi.

Is there any chance for new batch of 121GW ? I see that it is out of stock.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on March 22, 2018, 02:56:16 am
Dave still has a couple of thousand 121GW to deliver from his extremely successful Kickstarter campaign.  That needs to be fulfilled before any consideration can be given to him getting them "in stock" in his EEVblog store.

There was a delay from parts shortages earlier this year - and I don't know if they have been resolved or where that manufacturing is up to.  We do know the mechanical issue with the range switch has been sorted out, but considering the other problems at the moment, it is possible there may be some reservation about forging ahead with a mass run, just in case there needs to be a hardware revision.   << PLEASE NOTE, I am only guessing here. >>   If it is found these problems can be completely eliminated with firmware updates, then I would expect production to get up to speed at the earliest opportunity ... but Dave is the best person to give clear answers here.
Title: Re: EEVBlog 121GW Discussion thread
Post by: lukasz.kostka on March 22, 2018, 02:59:20 am
Thx.

Do you know if there is any channel / information source that I can subscribe to see when multimeters will be available ?
Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on March 22, 2018, 03:09:40 am
I believe Dave does Twitter - @eevblog .  I'd be pretty confident he would tweet about that.

(Sorry, I don't do Twitter.)


You could also check in here for updates, as you have.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Worsdier on March 22, 2018, 03:28:44 am
Hi.

Is there any chance for new batch of 121GW ? I see that it is out of stock.

I’m afraid you still have a long time to wait for stock. I backed one of the first 400 meters and it’s been 4 months overdue.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on March 22, 2018, 11:32:49 am
Thx.

Do you know if there is any channel / information source that I can subscribe to see when multimeters will be available ?

Sign up for the newsletter
http://www.eevblog.com/newsletter/ (http://www.eevblog.com/newsletter/)

Many people still ask, and I don't know why people seaming don't quite understand that I have to deliver the Kickstarter units first before I sell to the general public.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Seppy on March 22, 2018, 02:27:37 pm
At this point we are basically using the current user base as a testing platform to find and confirm bug fixes. There is nothing better than giving it to a few hundred people and getting feedback.

This is fine, but please "fix" things and don't "cover up".

The bluetooth transmission is broken by design and by implementation.
  • There is no data integrity, aka. CRC or something on records (design error)
  • The ASCII decimal/hex coding wastes more then 2/3 of the already scarce bluetooth bandwidth (design error)
  • You have to check every single byte received for plausibility (and you'll fail in a lot of cases) (implementation error)
  • If you look at the errors in the data it's clear that some buffer in the firmware get's overwritten (implementation error)

Would current owner prefer we not make interim firmware releases available for testing?

I'm fine with testing, no problem.

But the 1.07 -> 1.09 is not a fix, it's just trying to cover up above mentioned errors a bit better.

Start with fixing the missing CRC. Then errors can be detected reliably and automatically and one can trust the data received is what the firmware wanted to send.

As stated before there was actually a checksum. What was happening was the OS was dropping half the packet on some systems, we compacted the packet so that it fits into 19 bytes.

This means that the XOR checksum now reliably makes it into the transmission. There is an update to the multimeter App and firmware that improves the situation greatly but further testing is needed. If anybody needs help developing a script to read the packet feel free to contact me.

The BLE packet format is now in a document on the 121GW product page.

If you install version 1.10 of the firmware you will also need to update the app.
You can do that on the Google Play / Window Store, (at least when they approve the update).

Links for the mentioned documents and firmware can be found at:
https://www.eevblog.com/product/121gw/ (https://www.eevblog.com/product/121gw/)
Title: Re: EEVBlog 121GW Discussion thread
Post by: Fungus on March 22, 2018, 05:28:16 pm
Thx.

Do you know if there is any channel / information source that I can subscribe to see when multimeters will be available ?

Go here and search for "121G":

https://www.oreillyauto.com/ (https://www.oreillyauto.com/)

Title: Re: EEVBlog 121GW Discussion thread
Post by: Iagash on March 23, 2018, 12:30:42 am
If you install version 1.10 of the firmware you will also need to update the app.
You can do that on the Google Play / Window Store, (at least when they approve the update).

Thanks, first check findings:

The values displayed in VA mode by the app are still wrong:
meter displays (correctly, verified with other meter): 1966.2mVA DC, 4.3672V, 450.29 mA
app displays: 1966.2mVA DC, 2.1863V, 204.52 A

If I change the input to the meter for negative current, the meter displays the negative current correctly, but the app still displays the same wrong positive current.

So the the values are off around factor 2x, current displays A instead of mA.

This is DC mode, firmware 1.10, app version 5

The update rate is much higher now, thanks!

I'll check the documents and update my script and let you know what I find there.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Iagash on March 23, 2018, 03:03:35 am
If I change the input to the meter for negative current, the meter displays the negative current correctly, but the app still displays the same wrong positive current.

This is a bug in your app, Seppy. I get the correct sign value for the sub-display via bluetooth.

Longterm log is now running.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Elasia on March 23, 2018, 06:05:28 am
Thx.

Do you know if there is any channel / information source that I can subscribe to see when multimeters will be available ?

Sign up for the newsletter
http://www.eevblog.com/newsletter/ (http://www.eevblog.com/newsletter/)

Many people still ask, and I don't know why people seaming don't quite understand that I have to deliver the Kickstarter units first before I sell to the general public.

Simple... because its shiny!  .....  Squirrel!  That and they most likely don't comprehend your order book nor mass production and distribution of custom small batch electronics.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Iagash on March 23, 2018, 08:10:07 am
Ok, Version 1.10 is definitely a step forward but it still contains errors despite a correct checksum.

There is a pattern, when switching the second display from current to voltage in DC VA-mode the decimal point is wrong:
Code: [Select]
--
1521739280.909 2023-08 02342    Power DC (VA)  1966.3 mVA       DCA  205.12    0% f:  5%
1521739281.179 2023-08 02342    Power DC (VA)  1966.3 mVA       DCV  21.863    0% f:  5%
1521739281.517 2023-08 02342    Power DC (VA)  1966.3 mVA       DCV  2.1863    0% f:  5%
--
1521739349.017 2023-08 02342    Power DC (VA)  1967.2 mVA       DCA  204.99    0% f:  5%
1521739349.287 2023-08 02342    Power DC (VA)  1967.2 mVA       DCV  21.855    0% f:  5%
1521739349.557 2023-08 02342    Power DC (VA)  1967.2 mVA       DCV  2.1855    0% f:  5%
--
1521739615.442 2023-08 02342    Power DC (VA)  1966.9 mVA       DCA  204.99    0% f:  5%
1521739615.712 2023-08 02342    Power DC (VA)  1966.9 mVA       DCV  21.862    0% f:  5%
1521739615.914 2023-08 02342    Power DC (VA)  1967.1 mVA       DCV  2.1862    0% f:  5%
--

But sometimes it stays wrong:
Code: [Select]
--
1521741169.774 2023-08 02342    Power DC (VA)  1966.2 mVA       DCA  205.10    0% f:  5%
1521741170.044 2023-08 02342    Power DC (VA)  1966.3 mVA       DCV  21.866    0% f:  5%
1521741170.584 2023-08 02342    Power DC (VA)  1966.3 mVA       DCV  21.866    0% f:  5%
1521741170.854 2023-08 02342    Power DC (VA)  1966.3 mVA       DCV  21.866    0% f:  5%
1521741171.192 2023-08 02342    Power DC (VA)  1966.3 mVA       DCV  21.866    0% f:  5%
1521741171.327 2023-08 02342    Power DC (VA)  1966.3 mVA       DCV  21.866    0% f:  5%
1521741171.597 2023-08 02342    Power DC (VA)  1966.7 mVA       DCV  21.857    0% f:  5%
1521741171.799 2023-08 02342    Power DC (VA)  1966.7 mVA       DCV  21.857    0% f:  5%
1521741172.070 2023-08 02342    Power DC (VA)  1966.7 mVA       DCV  21.857    0% f:  5%
1521741172.272 2023-08 02342    Power DC (VA)  1966.7 mVA       DCV  21.857    0% f:  5%
1521741172.541 2023-08 02342    Power DC (VA)  1966.7 mVA       DCV  21.857    0% f:  5%
1521741172.880 2023-08 02342    Power DC (VA)  1966.7 mVA       DCV  21.857    0% f:  5%
1521741173.352 2023-08 02342    Power DC (VA)  1966.7 mVA       DCA  205.09    0% f:  5%
--

Sometimes I even get a wrong mode:
Code: [Select]
--
1521743502.116 2023-08 02342    Power DC (VA)  1968.8 mVA       DCA  204.66    0% f:  5%
1521743502.589 2000-00 00040 Voltage LowZ (V) -0.61975 V    48% f:  5%
1521743502.859 2023-08 02342    Power DC (VA)  1968.7 mVA       DCA  204.66    0% f:  5%
--

I collected arround 44k log records around 2k2 or 5% have a wrong checksum.

From the remaning 42k loglines with correct checksum 155 are broken, having either a wrong mode (66) a wrong decimal point(87) and 2 have some other parse error.
Title: Re: EEVBlog 121GW Discussion thread
Post by: HKJ on March 23, 2018, 08:16:10 am
From the remaning 42k loglines with correct checksum 155 are broken

A XOR is not guaranteed to catch more than one byte errors, once in a while a multi byte error will slip through.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Iagash on March 23, 2018, 08:43:35 am
Another error:

The bargraph display in the app doesn't match the display on the meter.
I also get "strange" values via bluetooth, but the document about the BLE format doesn't describe how the values should be interpreted and the gitlab repo of the app is not uptodate.

I question the sending of the bargraph data via BLE at all, since the bargraph is meant for fast updates, which seems useless to me via BLE with 4-5 updates per second we see now.

I would prefer if the meter would send the values it has but doesn't display on the meter, like temperature and sending always current and voltage in VA mode.
But this is not a bug, more a question of preference and usage.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Iagash on March 23, 2018, 09:08:57 am
From the remaning 42k loglines with correct checksum 155 are broken

A XOR is not guaranteed to catch more than one byte errors, once in a while a multi byte error will slip through.

Yes of course, but I'm still very glad to be able to throw out the guessing of digits.
The remaining errors can be found quite easily by checking the log lines with grep and awk.

The goal would be getting flow-control right between the CPU and the BLE module, then even no checksum would be needed as FrankBuss pointed out.

The errors with the decimal point are probably another bug in the firmware that has nothing to do with the wrong checksums.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Seppy on March 23, 2018, 11:32:16 am
Ok, Version 1.10 is definitely a step forward but it still contains errors despite a correct checksum.

There is a pattern, when switching the second display from current to voltage in DC VA-mode the decimal point is wrong:
Code: [Select]
--
1521739280.909 2023-08 02342    Power DC (VA)  1966.3 mVA       DCA  205.12    0% f:  5%
1521739281.179 2023-08 02342    Power DC (VA)  1966.3 mVA       DCV  21.863    0% f:  5%
1521739281.517 2023-08 02342    Power DC (VA)  1966.3 mVA       DCV  2.1863    0% f:  5%
--
1521739349.017 2023-08 02342    Power DC (VA)  1967.2 mVA       DCA  204.99    0% f:  5%
1521739349.287 2023-08 02342    Power DC (VA)  1967.2 mVA       DCV  21.855    0% f:  5%
1521739349.557 2023-08 02342    Power DC (VA)  1967.2 mVA       DCV  2.1855    0% f:  5%
--
1521739615.442 2023-08 02342    Power DC (VA)  1966.9 mVA       DCA  204.99    0% f:  5%
1521739615.712 2023-08 02342    Power DC (VA)  1966.9 mVA       DCV  21.862    0% f:  5%
1521739615.914 2023-08 02342    Power DC (VA)  1967.1 mVA       DCV  2.1862    0% f:  5%
--

But sometimes it stays wrong:
Code: [Select]
--
1521741169.774 2023-08 02342    Power DC (VA)  1966.2 mVA       DCA  205.10    0% f:  5%
1521741170.044 2023-08 02342    Power DC (VA)  1966.3 mVA       DCV  21.866    0% f:  5%
1521741170.584 2023-08 02342    Power DC (VA)  1966.3 mVA       DCV  21.866    0% f:  5%
1521741170.854 2023-08 02342    Power DC (VA)  1966.3 mVA       DCV  21.866    0% f:  5%
1521741171.192 2023-08 02342    Power DC (VA)  1966.3 mVA       DCV  21.866    0% f:  5%
1521741171.327 2023-08 02342    Power DC (VA)  1966.3 mVA       DCV  21.866    0% f:  5%
1521741171.597 2023-08 02342    Power DC (VA)  1966.7 mVA       DCV  21.857    0% f:  5%
1521741171.799 2023-08 02342    Power DC (VA)  1966.7 mVA       DCV  21.857    0% f:  5%
1521741172.070 2023-08 02342    Power DC (VA)  1966.7 mVA       DCV  21.857    0% f:  5%
1521741172.272 2023-08 02342    Power DC (VA)  1966.7 mVA       DCV  21.857    0% f:  5%
1521741172.541 2023-08 02342    Power DC (VA)  1966.7 mVA       DCV  21.857    0% f:  5%
1521741172.880 2023-08 02342    Power DC (VA)  1966.7 mVA       DCV  21.857    0% f:  5%
1521741173.352 2023-08 02342    Power DC (VA)  1966.7 mVA       DCA  205.09    0% f:  5%
--

Sometimes I even get a wrong mode:
Code: [Select]
--
1521743502.116 2023-08 02342    Power DC (VA)  1968.8 mVA       DCA  204.66    0% f:  5%
1521743502.589 2000-00 00040 Voltage LowZ (V) -0.61975 V    48% f:  5%
1521743502.859 2023-08 02342    Power DC (VA)  1968.7 mVA       DCA  204.66    0% f:  5%
--

I collected arround 44k log records around 2k2 or 5% have a wrong checksum.

From the remaning 42k loglines with correct checksum 155 are broken, having either a wrong mode (66) a wrong decimal point(87) and 2 have some other parse error.

It does appear that you have the wrong app, try the other app avaliable on the app store. This is not the format that my app logs, so yeah it must be the wrong app.

https://play.google.com/store/apps/details?id=eevblog.x121gw&hl=en

Update 1:
I have reproduced the voltage reading error in VA mode, am investigating whether the packet is the cause or the app, will update this post soon.

Update 2:
There is an issue with the voltage display (in the app on the sub display) in the VA mode, it appears to behave like a signed/unsigned issue with the formation of the packet, this means that for voltages above (32768 - 1 ish +- the calibrated offset) the value appears to result in invalid readings. It is possible still that the App has caused the issue but it is looking quite unlikely.
This will be resolved as soon as possible.

Note: The decimal position for the mVA appears also to be reported incorrectly in the packet (only those modes) these issues will also be dealt with soon.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Iagash on March 23, 2018, 11:41:25 pm

It does appear that you have the wrong app, try the other app avaliable on the app store. This is not the format that my app logs, so yeah it must be the wrong app.

https://play.google.com/store/apps/details?id=eevblog.x121gw&hl=en

Yes Seppy, it's the wrong app, I'm sorry. The output is from my BLE linux script which I adapted to the new format according to the BLE documentation.

I can't do extended logging with your app, since I have only one BLE capable Android device and no BLE capable Windows and not even a Windows with a Microsoft store. The Android phone is my phone and has to follow me around. So I can't leave it untouched next to the meter for long. I just use it to compare the values displayed by the app to the output of my script.

I also had the problem with your android app, that I couldn't save the log when I left it running once over night. When pressing save the app just froze for some seconds and then continued. Maybe my phone has too little memory.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Iagash on March 24, 2018, 09:50:11 pm
I added plausibility checks back into my script. I'm checking the year and month the meter is transmitting, since it seems to be always the same.
Then I added printing the data of invalid records. The log below shows the invalid data between two correct records. As you can see, they don't happen very often.

Maybe you can check, if you can also see this pattern with your app. The last column shows the percentage of records with invalid xor checksum. So around 5-6% of the records are broken. I have not yet analyzed these records.

Code: [Select]
20180324-10:07:40.176 2023-08 02342    Power DC (VA)  2005.9 mVA       DCV  2.0987    0% f:  5%
20180324-10:07:40.648 error: unparsable record: Invalid year (0)
20180324-10:07:40.648 error: data: f2 00 00 01 40 00 d5 f2 17 80 23 42 18 00 4e 60 01 04 51
20180324-10:07:40.783 error: skiped 7 input bytes
20180324-10:07:40.783 2023-08 02342    Power DC (VA)  2006.4 mVA       DCV  2.0978    0% f:  5%
--
20180324-10:08:42.006 2023-08 02342    Power DC (VA)  2006.2 mVA       DCV  2.0978    0% f:  5%
20180324-10:08:42.478 error: unparsable record: Invalid year (0)
20180324-10:08:42.478 error: data: f2 00 00 01 40 00 eb f2 17 80 23 42 18 00 4e 5e 01 04 51
20180324-10:08:42.614 error: skiped 7 input bytes
20180324-10:08:42.614 2023-08 02342    Power DC (VA)  2006.2 mVA       DCV  2.0978    0% f:  6%
--
20180324-10:09:19.199 2023-08 02342    Power DC (VA)  2006.2 mVA       DCV  2.0978    0% f:  5%
20180324-10:09:19.671 error: unparsable record: Invalid year (0)
20180324-10:09:19.671 error: data: f2 00 00 01 40 00 eb f2 17 80 23 42 18 00 4e 5e 01 04 51
20180324-10:09:19.806 error: skiped 7 input bytes
20180324-10:09:19.806 2023-08 02342    Power DC (VA)  2006.2 mVA       DCV  2.0978    0% f:  5%
--
20180324-10:11:36.427 2023-08 02342    Power DC (VA)  2006.8 mVA       DCV  2.0978    0% f:  6%
20180324-10:11:36.900 error: unparsable record: Invalid year (0)
20180324-10:11:36.900 error: data: f2 00 00 01 40 00 d1 f2 17 80 23 42 18 00 4e 64 01 04 51
20180324-10:11:37.035 error: skiped 7 input bytes
20180324-10:11:37.035 2023-08 02342    Power DC (VA)  2006.8 mVA       DCV  2.0978    0% f:  6%
--
20180324-10:12:51.825 2023-08 02342    Power DC (VA)  2006.6 mVA       DCV  2.0978    0% f:  6%
20180324-10:12:52.297 error: unparsable record: Invalid year (0)
20180324-10:12:52.297 error: data: f2 00 00 01 40 00 d7 f2 17 80 23 42 18 00 4e 62 01 04 51
20180324-10:12:52.433 error: skiped 7 input bytes
20180324-10:12:52.433 2023-08 02342    Power DC (VA)  2006.6 mVA       DCV  2.0978    0% f:  6%
--
20180324-10:16:26.477 2023-08 02342    Power DC (VA)  2006.6 mVA       DCV  2.0978    0% f:  6%
20180324-10:16:26.949 error: unparsable record: Invalid year (0)
20180324-10:16:26.949 error: data: f2 00 00 01 40 00 d7 f2 17 80 23 42 18 00 4e 62 01 04 51
20180324-10:16:27.084 error: skiped 7 input bytes
20180324-10:16:27.084 2023-08 02342    Power DC (VA)  2006.6 mVA       DCV  2.0978    0% f:  6%
--
20180324-10:18:36.415 2023-08 02342    Power DC (VA)  2006.8 mVA       DCV  2.0978    0% f:  5%
20180324-10:18:36.887 error: unparsable record: Invalid year (0)
20180324-10:18:36.887 error: data: f2 00 00 01 40 00 d1 f2 17 80 23 42 18 00 4e 64 01 04 51
20180324-10:18:37.022 error: skiped 7 input bytes
20180324-10:18:37.022 2023-08 02342    Power DC (VA)  2006.8 mVA       DCV  2.0978    0% f:  6%
--
20180324-10:37:36.767 2023-08 02342    Power DC (VA)  2006.8 mVA       DCV  2.0978    0% f:  5%
20180324-10:37:37.239 error: unparsable record: Invalid year (0)
20180324-10:37:37.239 error: data: f2 00 00 01 40 00 d1 f2 17 80 23 42 18 00 4e 64 01 04 51
20180324-10:37:37.374 error: skiped 7 input bytes
20180324-10:37:37.374 2023-08 02342    Power DC (VA)  2006.8 mVA       DCV  2.0978    0% f:  5%
--
20180324-10:40:23.155 2023-08 02342    Power DC (VA)  2006.8 mVA       DCV  2.0978    0% f:  6%
20180324-10:40:23.628 error: unparsable record: Invalid year (0)
20180324-10:40:23.628 error: data: f2 00 00 01 40 00 d1 f2 17 80 23 42 18 00 4e 64 01 04 51
20180324-10:40:23.763 error: skiped 7 input bytes
20180324-10:40:23.763 2023-08 02342    Power DC (VA)  2006.8 mVA       DCV  2.0979    0% f:  6%
--
20180324-10:41:13.916 2023-08 02342    Power DC (VA)  2006.8 mVA       DCV  2.0978    0% f:  6%
20180324-10:41:14.388 error: unparsable record: Invalid year (0)
20180324-10:41:14.388 error: data: f2 00 00 01 40 00 d1 f2 17 80 23 42 18 00 4e 64 01 04 51
20180324-10:41:14.523 error: skiped 7 input bytes
20180324-10:41:14.523 2023-08 02342    Power DC (VA)  2006.8 mVA       DCV  2.0978    0% f:  6%
--
20180324-10:45:01.864 2023-08 02342    Power DC (VA)  2007.1 mVA       DCV  2.0978    0% f:  6%
20180324-10:45:02.337 error: unparsable record: Invalid year (0)
20180324-10:45:02.337 error: data: f2 00 00 01 40 00 d2 f2 17 80 23 42 18 00 4e 67 01 04 51
20180324-10:45:02.472 error: skiped 7 input bytes
20180324-10:45:02.472 2023-08 02342    Power DC (VA)  2007.1 mVA       DCV  2.0978    0% f:  6%
--
20180324-10:48:21.463 2023-08 02342    Power DC (VA)  2006.8 mVA       DCV  2.0978    0% f:  6%
20180324-10:48:21.935 error: unparsable record: Invalid year (0)
20180324-10:48:21.935 error: data: f2 00 00 01 40 00 d1 f2 17 80 23 42 18 00 4e 64 01 04 51
20180324-10:48:22.071 error: skiped 7 input bytes
20180324-10:48:22.071 2023-08 02342    Power DC (VA)  2006.8 mVA       DCV  2.0978    0% f:  6%
--
20180324-10:51:01.102 2023-08 02342    Power DC (VA)  2006.8 mVA       DCV  2.0978    0% f:  6%
20180324-10:51:01.574 error: unparsable record: Invalid year (0)
20180324-10:51:01.574 error: data: f2 00 00 01 40 00 d1 f2 17 80 23 42 18 00 4e 64 01 04 51
20180324-10:51:01.709 error: skiped 7 input bytes
20180324-10:51:01.709 2023-08 02342    Power DC (VA)  2006.8 mVA       DCV  2.0978    0% f:  6%
--
20180324-10:52:48.427 2023-08 02342    Power DC (VA)  2008.6 mVA       DCA  204.66    0% f:  6%
20180324-10:52:48.900 error: unparsable record: Invalid year (0)
20180324-10:52:48.900 error: data: f2 00 00 01 40 00 cf f2 17 80 23 42 18 00 4e 76 15 02 4f
20180324-10:52:49.035 error: skiped 7 input bytes
20180324-10:52:49.035 2023-08 02342    Power DC (VA)  2008.6 mVA       DCA  204.66    0% f:  6%
--
20180324-11:02:35.006 2023-08 02342    Power DC (VA)  2006.8 mVA       DCV  2.0980    0% f:  5%
20180324-11:02:35.478 error: unparsable record: Invalid year (0)
20180324-11:02:35.478 error: data: f2 00 00 01 40 00 d0 f2 17 80 23 42 18 00 4e 65 01 04 51
20180324-11:02:35.613 error: skiped 7 input bytes
20180324-11:02:35.613 2023-08 02342    Power DC (VA)  2006.9 mVA       DCV  2.0978    0% f:  5%
--
20180324-11:03:35.824 2023-08 02342    Power DC (VA)  2006.4 mVA       DCV  2.0978    0% f:  5%
20180324-11:03:36.296 error: unparsable record: Invalid year (0)
20180324-11:03:36.296 error: data: f2 00 00 01 40 00 d5 f2 17 80 23 42 18 00 4e 60 01 04 51
20180324-11:03:36.431 error: skiped 7 input bytes
20180324-11:03:36.431 2023-08 02342    Power DC (VA)  2006.4 mVA       DCV  2.0978    0% f:  6%
--
20180324-11:14:06.817 2023-08 02342    Power DC (VA)  2006.8 mVA       DCV  2.0978    0% f:  6%
20180324-11:14:07.290 error: unparsable record: Invalid year (0)
20180324-11:14:07.290 error: data: f2 00 00 01 40 00 d1 f2 17 80 23 42 18 00 4e 64 01 04 51
20180324-11:14:07.425 error: skiped 7 input bytes
20180324-11:14:07.425 2023-08 02342    Power DC (VA)  2006.8 mVA       DCV  2.0978    0% f:  6%
--
20180324-11:21:51.963 2023-08 02342    Power DC (VA)  2007.0 mVA       DCV  2.0978    0% f:  6%
20180324-11:21:52.435 error: unparsable record: Invalid year (0)
20180324-11:21:52.435 error: data: f2 00 00 01 40 00 d3 f2 17 80 23 42 18 00 4e 66 01 04 51
20180324-11:21:52.570 error: skiped 7 input bytes
20180324-11:21:52.570 2023-08 02342    Power DC (VA)  2007.0 mVA       DCV  2.0978    0% f:  6%
--
20180324-11:33:36.262 2023-08 02342    Power DC (VA)  2007.8 mVA       DCA  204.75    0% f:  6%
20180324-11:33:36.734 error: unparsable record: Invalid year (0)
20180324-11:33:36.734 error: data: f2 00 00 01 40 00 db f2 17 80 23 42 18 00 4e 6e 01 04 51
20180324-11:33:36.870 error: skiped 7 input bytes
20180324-11:33:36.870 2023-08 02342    Power DC (VA)  2007.8 mVA       DCV  2.0978    0% f:  6%
--
20180324-11:36:30.886 2023-08 02342    Power DC (VA)  2007.2 mVA       DCV  2.0978    0% f:  6%
20180324-11:36:31.358 error: unparsable record: Invalid year (0)
20180324-11:36:31.358 error: data: f2 00 00 01 40 00 dd f2 17 80 23 42 18 00 4e 68 01 04 51
20180324-11:36:31.493 error: skiped 7 input bytes
20180324-11:36:31.493 2023-08 02342    Power DC (VA)  2007.2 mVA       DCV  2.0978    0% f:  6%
Title: Re: EEVBlog 121GW Discussion thread
Post by: Iagash on March 26, 2018, 06:38:48 am
Here are some records with failing xor checksums:

Code: [Select]
20180325-21:31:47.828 error: invalid checksum: f2 17 80 23 42 18 00 25 45 01 04 70 1d 00 00 04 40 80 50
20180325-21:31:52.351 error: invalid checksum: f2 17 80 23 42 18 00 25 49 01 04 70 25 00 00 04 08 00 64
20180325-21:32:01.463 error: invalid checksum: f2 17 80 23 42 18 00 25 45 15 02 fb 1f 00 00 04 40 00 4e
20180325-21:32:06.053 error: invalid checksum: f2 17 80 23 42 06 00 25 46 01 04 70 20 00 00 04 40 00 6e
20180325-21:32:07.741 error: invalid checksum: f2 17 80 23 42 18 00 25 40 21 02 7e 22 00 00 04 40 00 76
20180325-21:32:11.521 error: invalid checksum: f2 17 80 23 42 18 00 25 47 01 04 70 01 00 00 04 40 00 6c
20180325-21:32:20.566 error: invalid checksum: f2 17 80 23 42 18 00 25 49 15 02 7e 07 00 00 04 40 00 43
20180325-21:32:25.089 error: invalid checksum: f2 17 80 23 42 18 40 25 43 01 04 70 16 00 00 04 40 00 5d
20180325-21:32:26.844 error: invalid checksum: f2 17 80 23 42 18 00 25 a9 15 02 7e 21 00 00 04 40 00 0a
20180325-21:32:29.611 error: invalid checksum: f2 17 80 88 42 18 00 25 42 01 04 70 0c 00 00 04 40 00 46
20180325-21:32:31.366 error: invalid checksum: f2 17 80 23 42 18 00 22 42 01 04 70 0c 00 00 04 40 00 46
20180325-21:32:35.889 error: invalid checksum: f2 17 80 23 42 0c 00 25 44 01 04 70 14 00 00 04 40 00 58
20180325-21:32:48.714 error: invalid checksum: f2 17 80 23 42 18 00 25 40 01 00 70 0b 00 00 04 40 00 43
20180325-21:32:53.236 error: invalid checksum: f2 17 80 23 21 18 00 25 3e 15 02 7e 1d 00 00 04 40 00 37
20180325-21:32:54.991 error: invalid checksum: f2 17 80 23 42 18 00 25 09 01 04 70 01 00 00 04 40 00 37
20180325-21:32:57.759 error: invalid checksum: f2 17 80 23 42 01 00 25 3d 15 02 7e 20 00 00 04 40 00 09
20180325-21:32:59.446 error: invalid checksum: f2 17 80 23 10 18 00 25 3d 15 02 7e 20 00 00 04 40 00 09
20180325-21:33:09.571 error: invalid checksum: f2 17 80 23 42 18 00 25 45 15 02 7e 07 00 00 04 40 00 4e
20180325-21:33:12.339 error: invalid checksum: f2 17 80 23 42 01 00 25 43 01 04 70 16 00 00 04 40 00 5d
20180325-21:33:14.161 error: invalid checksum: f2 17 80 23 42 18 00 25 43 20 04 70 16 00 00 04 40 00 5d

I don't really understand what's happening here. It looks a bit like random bit errors. could it be a birate mismatch between CPU and BLE module?

Maybe someone with more experience with this kind of errors can comment on this.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Seppy on March 26, 2018, 11:40:36 am

It does appear that you have the wrong app, try the other app avaliable on the app store. This is not the format that my app logs, so yeah it must be the wrong app.

https://play.google.com/store/apps/details?id=eevblog.x121gw&hl=en

I also had the problem with your android app, that I couldn't save the log when I left it running once over night. When pressing save the app just froze for some seconds and then continued. Maybe my phone has too little memory.

I'll look into this, not sure what caused it but i'll do my best to reproduce, it may take a while to reproduce these type of issues can sometimes take a while to figure out the exact mechanism as its likely something specific about the android API. I'll get back to you or just release a fix as an update if it is reproducible.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Iagash on March 26, 2018, 10:52:35 pm
I'll look into this, not sure what caused it but i'll do my best to reproduce, it may take a while to reproduce these type of issues can sometimes take a while to figure out the exact mechanism as its likely something specific about the android API. I'll get back to you or just release a fix as an update if it is reproducible.

Thanks, but don't spend much time on this. Short logs are working fine. The fault could also be my phone I just tried it once.

I'd be much more interested if you can see the same data errors that I see with my linux script.

Maybe you could add logging of these failed records raw data to your app, so that I can compare these?
Title: Re: EEVBlog 121GW Discussion thread
Post by: FrankBuss on March 27, 2018, 05:16:13 am
Here are some records with failing xor checksums:

Code: [Select]
20180325-21:31:47.828 error: invalid checksum: f2 17 80 23 42 18 00 25 45 01 04 70 1d 00 00 04 40 80 50
20180325-21:31:52.351 error: invalid checksum: f2 17 80 23 42 18 00 25 49 01 04 70 25 00 00 04 08 00 64
20180325-21:32:01.463 error: invalid checksum: f2 17 80 23 42 18 00 25 45 15 02 fb 1f 00 00 04 40 00 4e
20180325-21:32:06.053 error: invalid checksum: f2 17 80 23 42 06 00 25 46 01 04 70 20 00 00 04 40 00 6e
20180325-21:32:07.741 error: invalid checksum: f2 17 80 23 42 18 00 25 40 21 02 7e 22 00 00 04 40 00 76
20180325-21:32:11.521 error: invalid checksum: f2 17 80 23 42 18 00 25 47 01 04 70 01 00 00 04 40 00 6c
20180325-21:32:20.566 error: invalid checksum: f2 17 80 23 42 18 00 25 49 15 02 7e 07 00 00 04 40 00 43
20180325-21:32:25.089 error: invalid checksum: f2 17 80 23 42 18 40 25 43 01 04 70 16 00 00 04 40 00 5d
20180325-21:32:26.844 error: invalid checksum: f2 17 80 23 42 18 00 25 a9 15 02 7e 21 00 00 04 40 00 0a
20180325-21:32:29.611 error: invalid checksum: f2 17 80 88 42 18 00 25 42 01 04 70 0c 00 00 04 40 00 46
20180325-21:32:31.366 error: invalid checksum: f2 17 80 23 42 18 00 22 42 01 04 70 0c 00 00 04 40 00 46
20180325-21:32:35.889 error: invalid checksum: f2 17 80 23 42 0c 00 25 44 01 04 70 14 00 00 04 40 00 58
20180325-21:32:48.714 error: invalid checksum: f2 17 80 23 42 18 00 25 40 01 00 70 0b 00 00 04 40 00 43
20180325-21:32:53.236 error: invalid checksum: f2 17 80 23 21 18 00 25 3e 15 02 7e 1d 00 00 04 40 00 37
20180325-21:32:54.991 error: invalid checksum: f2 17 80 23 42 18 00 25 09 01 04 70 01 00 00 04 40 00 37
20180325-21:32:57.759 error: invalid checksum: f2 17 80 23 42 01 00 25 3d 15 02 7e 20 00 00 04 40 00 09
20180325-21:32:59.446 error: invalid checksum: f2 17 80 23 10 18 00 25 3d 15 02 7e 20 00 00 04 40 00 09
20180325-21:33:09.571 error: invalid checksum: f2 17 80 23 42 18 00 25 45 15 02 7e 07 00 00 04 40 00 4e
20180325-21:33:12.339 error: invalid checksum: f2 17 80 23 42 01 00 25 43 01 04 70 16 00 00 04 40 00 5d
20180325-21:33:14.161 error: invalid checksum: f2 17 80 23 42 18 00 25 43 20 04 70 16 00 00 04 40 00 5d

I don't really understand what's happening here. It looks a bit like random bit errors. could it be a birate mismatch between CPU and BLE module?

Maybe someone with more experience with this kind of errors can comment on this.

This looks like a baudrate problem, or maybe wrong start bit detection or something like this. E.g. when 0x42 turns into 0x21, one bit shifted to the right. Same for 0x18 turning int 0x0c, one bit shifted.

Very unlikely that it has anything to do with the RF transfer from the Bluetooth module to the receiver, because as I noted earlier, BLE has a sophisticated error correction. Not just xor, but CRC, which is easy to calculate with tables, I've implemented this once myself for another product. You can verify this if you increase the distance: there shouldn't be more errors, but it gets slower, because packets gets resend, at least when I tested it with my Blue Gecko Silabs IC, which had no packet errors at all at the application level.

Maybe you can measure the RX/TX lines between the Bluetooth module and the CPU to check if the baudrate is exact in your multimeter, if David can't reproduce it?
Title: Re: EEVBlog 121GW Discussion thread
Post by: plexus on March 27, 2018, 06:37:03 am
I would love an iphone app for the 121GW that is better than the existing one in the app store. Better GUI and user experience!
Title: Re: EEVBlog 121GW Discussion thread
Post by: Seppy on March 27, 2018, 04:40:02 pm
Here are some records with failing xor checksums:

Code: [Select]
20180325-21:31:47.828 error: invalid checksum: f2 17 80 23 42 18 00 25 45 01 04 70 1d 00 00 04 40 80 50
20180325-21:31:52.351 error: invalid checksum: f2 17 80 23 42 18 00 25 49 01 04 70 25 00 00 04 08 00 64
20180325-21:32:01.463 error: invalid checksum: f2 17 80 23 42 18 00 25 45 15 02 fb 1f 00 00 04 40 00 4e
20180325-21:32:06.053 error: invalid checksum: f2 17 80 23 42 06 00 25 46 01 04 70 20 00 00 04 40 00 6e
20180325-21:32:07.741 error: invalid checksum: f2 17 80 23 42 18 00 25 40 21 02 7e 22 00 00 04 40 00 76
20180325-21:32:11.521 error: invalid checksum: f2 17 80 23 42 18 00 25 47 01 04 70 01 00 00 04 40 00 6c
20180325-21:32:20.566 error: invalid checksum: f2 17 80 23 42 18 00 25 49 15 02 7e 07 00 00 04 40 00 43
20180325-21:32:25.089 error: invalid checksum: f2 17 80 23 42 18 40 25 43 01 04 70 16 00 00 04 40 00 5d
20180325-21:32:26.844 error: invalid checksum: f2 17 80 23 42 18 00 25 a9 15 02 7e 21 00 00 04 40 00 0a
20180325-21:32:29.611 error: invalid checksum: f2 17 80 88 42 18 00 25 42 01 04 70 0c 00 00 04 40 00 46
20180325-21:32:31.366 error: invalid checksum: f2 17 80 23 42 18 00 22 42 01 04 70 0c 00 00 04 40 00 46
20180325-21:32:35.889 error: invalid checksum: f2 17 80 23 42 0c 00 25 44 01 04 70 14 00 00 04 40 00 58
20180325-21:32:48.714 error: invalid checksum: f2 17 80 23 42 18 00 25 40 01 00 70 0b 00 00 04 40 00 43
20180325-21:32:53.236 error: invalid checksum: f2 17 80 23 21 18 00 25 3e 15 02 7e 1d 00 00 04 40 00 37
20180325-21:32:54.991 error: invalid checksum: f2 17 80 23 42 18 00 25 09 01 04 70 01 00 00 04 40 00 37
20180325-21:32:57.759 error: invalid checksum: f2 17 80 23 42 01 00 25 3d 15 02 7e 20 00 00 04 40 00 09
20180325-21:32:59.446 error: invalid checksum: f2 17 80 23 10 18 00 25 3d 15 02 7e 20 00 00 04 40 00 09
20180325-21:33:09.571 error: invalid checksum: f2 17 80 23 42 18 00 25 45 15 02 7e 07 00 00 04 40 00 4e
20180325-21:33:12.339 error: invalid checksum: f2 17 80 23 42 01 00 25 43 01 04 70 16 00 00 04 40 00 5d
20180325-21:33:14.161 error: invalid checksum: f2 17 80 23 42 18 00 25 43 20 04 70 16 00 00 04 40 00 5d

I don't really understand what's happening here. It looks a bit like random bit errors. could it be a birate mismatch between CPU and BLE module?

Maybe someone with more experience with this kind of errors can comment on this.

This looks like a baudrate problem, or maybe wrong start bit detection or something like this. E.g. when 0x42 turns into 0x21, one bit shifted to the right. Same for 0x18 turning int 0x0c, one bit shifted.

Very unlikely that it has anything to do with the RF transfer from the Bluetooth module to the receiver, because as I noted earlier, BLE has a sophisticated error correction. Not just xor, but CRC, which is easy to calculate with tables, I've implemented this once myself for another product. You can verify this if you increase the distance: there shouldn't be more errors, but it gets slower, because packets gets resend, at least when I tested it with my Blue Gecko Silabs IC, which had no packet errors at all at the application level.

Maybe you can measure the RX/TX lines between the Bluetooth module and the CPU to check if the baudrate is exact in your multimeter, if David can't reproduce it?

Alright so I've logged data for 2 minutes on BLE and UART then validated the packets, it doesn't appear i'm getting any of the bad packets on android.
Similarly on windows there were no bad packets.

Do you have any specific conditions which might help reproduce this issue.

NOTE: If you compile my main C++ file be sure to set struct alignment to be for bytes not like 32 bit integers or something, often the default is not byte.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Iagash on March 27, 2018, 07:50:33 pm

Alright so I've logged data for 2 minutes on BLE and UART then validated the packets, it doesn't appear i'm getting any of the bad packets on android.
Similarly on windows there were no bad packets.

Do you have any specific conditions which might help reproduce this issue.

NOTE: If you compile my main C++ file be sure to set struct alignment to be for bytes not like 32 bit integers or something, often the default is not byte.

Thanks a lot. Yes, your data looks good.

Can you explain how to log the raw data on android?

Then I'd like to try this with my meter to see if the problem is still there.

I tried with 3 different linux systems, my desktop, a thinkpad X230 and a thinkpad X220. They all show the same invalid records.

Maybe I have a bad meter?
Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on March 27, 2018, 09:04:15 pm
Just a question to clear it from the discussion....

Since this communication is still an RF link - have you tried alternate orientations between Tx and Rx, different distances, different environmental elements, such as RF reflective structures, RFI, etc?
Title: Re: EEVBlog 121GW Discussion thread
Post by: Seppy on March 28, 2018, 11:41:14 am

Alright so I've logged data for 2 minutes on BLE and UART then validated the packets, it doesn't appear i'm getting any of the bad packets on android.
Similarly on windows there were no bad packets.

Do you have any specific conditions which might help reproduce this issue.

NOTE: If you compile my main C++ file be sure to set struct alignment to be for bytes not like 32 bit integers or something, often the default is not byte.

Thanks a lot. Yes, your data looks good.

Can you explain how to log the raw data on android?

Then I'd like to try this with my meter to see if the problem is still there.

I tried with 3 different linux systems, my desktop, a thinkpad X230 and a thinkpad X220. They all show the same invalid records.

Maybe I have a bad meter?

At the moment raw packet logging is not a feature of the app, I use debug outputs (in visual studio, with debug mode) to get the data.

There are a fair few apps on the play store which seem suitable, I haven't used these but they appear to do what you want:
https://play.google.com/store/apps/details?id=com.zicasoftware.ziblemonitor
https://play.google.com/store/apps/details?id=com.edodm85.bluetoothbleterminal.free


Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on March 28, 2018, 12:44:27 pm
I tried with 3 different linux systems, my desktop, a thinkpad X230 and a thinkpad X220. They all show the same invalid records.
Maybe I have a bad meter?

Do you have any issues at all with the range switch?
There is a possibility that could be an issue.
Title: Re: EEVBlog 121GW Discussion thread
Post by: FrankBuss on March 28, 2018, 06:38:15 pm
I tried with 3 different linux systems, my desktop, a thinkpad X230 and a thinkpad X220. They all show the same invalid records.
Maybe I have a bad meter?

Do you have any issues at all with the range switch?
There is a possibility that could be an issue.

How could the range switch cause invalid xor checksums?
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on March 28, 2018, 06:41:13 pm
I tried with 3 different linux systems, my desktop, a thinkpad X230 and a thinkpad X220. They all show the same invalid records.
Maybe I have a bad meter?

Do you have any issues at all with the range switch?
There is a possibility that could be an issue.

I was thinking of the spurious VA values. We no longer get these as it's been (as far as we can tell) fixed in software. So if spurious values are being seen, maybe that's a possible cause?
But if it's a checksum thing, then forget I said it.
But as I believe David (seppy) has said, we are no longer getting corrupted data, and hence no more checksum errors.

How could the range switch cause invalid xor checksums?
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on March 28, 2018, 06:45:55 pm
I'll look into this, not sure what caused it but i'll do my best to reproduce, it may take a while to reproduce these type of issues can sometimes take a while to figure out the exact mechanism as its likely something specific about the android API. I'll get back to you or just release a fix as an update if it is reproducible.

Thanks, but don't spend much time on this. Short logs are working fine. The fault could also be my phone I just tried it once.
I'd be much more interested if you can see the same data errors that I see with my linux script.
Maybe you could add logging of these failed records raw data to your app, so that I can compare these?

Is anyone else having issues with the bluetooth data? If not then we probably don't have a choice at this point but to consider the bluetooth issues fixed, as always subject the future any future identified and repeatable issues.
UEi fixed a bug in the micro send routine sending spurious data, and we have shortened (more than halved) the packet size to reduce known packet loss were were seeing. We no see no issues at all at our end on our app.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Iagash on March 28, 2018, 07:29:04 pm

At the moment raw packet logging is not a feature of the app, I use debug outputs (in visual studio, with debug mode) to get the data.

There are a fair few apps on the play store which seem suitable, I haven't used these but they appear to do what you want:
https://play.google.com/store/apps/details?id=com.zicasoftware.ziblemonitor
https://play.google.com/store/apps/details?id=com.edodm85.bluetoothbleterminal.free

Thanks.

I tried these and they can talk to the meter, but seem unable to receive and log the data packets.

Title: Re: EEVBlog 121GW Discussion thread
Post by: Iagash on March 28, 2018, 07:37:37 pm

I was thinking of the spurious VA values. We no longer get these as it's been (as far as we can tell) fixed in software. So if spurious values are being seen, maybe that's a possible cause?
But if it's a checksum thing, then forget I said it.
But as I believe David (seppy) has said, we are no longer getting corrupted data, and hence no more checksum errors.

How could the range switch cause invalid xor checksums?

I don't see spurious VA values as in the early versions of the firmware.

With V1.10 I still see wrong voltage and current displays in certain parts of the measuring range, I see a spurious wrong decimal point in current display and I see wrong range display (A instead of mA) in the current display. All of this in DC VA-mode.

Apart from that the displayed values are consistently wrong.

I guess the invalid checksums must then be some electrical problem in my meter if no one else can see them.

As there seems no way to debug it further, I can't help you there.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on March 28, 2018, 08:37:44 pm
With V1.10 I still see wrong voltage and current displays in certain parts of the measuring range, I see a spurious wrong decimal point in current display and I see wrong range display (A instead of mA) in the current display. All of this in DC VA-mode.
Apart from that the displayed values are consistently wrong.

On the meter display or the app display? (or both)
Does the SD card logged data show correct or incorrect readings?

Quote
I guess the invalid checksums must then be some electrical problem in my meter if no one else can see them.

Again, how are you validating your checksums? with your own software?
Title: Re: EEVBlog 121GW Discussion thread
Post by: Iagash on March 28, 2018, 08:55:59 pm
With V1.10 I still see wrong voltage and current displays in certain parts of the measuring range, I see a spurious wrong decimal point in current display and I see wrong range display (A instead of mA) in the current display. All of this in DC VA-mode.
Apart from that the displayed values are consistently wrong.

On the meter display or the app display? (or both)

Only in the app, the meter is correct.

Does the SD card logged data show correct or incorrect readings?

I didn't try the SD-card since the log is of no use to me without timestamps.

I guess the invalid checksums must then be some electrical problem in my meter if no one else can see them.

Again, how are you validating your checksums? with your own software?

Yes with my own software, you have the raw readings in the post above, you could verify yourself.
Title: Re: EEVBlog 121GW Discussion thread
Post by: plexus on March 29, 2018, 06:01:20 am
I updated the meter to 1.10 and now the iphone app doesn't work. it connects (apparently) but there is no meter display in the app.

Any ideas? Fixes? Any idea when a real eevblog iOS app will be released?
Title: Re: EEVBlog 121GW Discussion thread
Post by: HKJ on March 29, 2018, 06:28:36 am
I updated the meter to 1.10 and now the iphone app doesn't work. it connects (apparently) but there is no meter display in the app.

Any ideas? Fixes? Any idea when a real eevblog iOS app will be released?

The Bluetooth protocol changed, you have to use the correct application version (I do not know that yet, I am still waiting on my meter).
Title: Re: EEVBlog 121GW Discussion thread
Post by: plexus on March 29, 2018, 06:31:18 am
I updated the meter to 1.10 and now the iphone app doesn't work. it connects (apparently) but there is no meter display in the app.

Any ideas? Fixes? Any idea when a real eevblog iOS app will be released?

The Bluetooth protocol changed, you have to use the correct application version (I do not know that yet, I am still waiting on my meter).

EEVBlog: any ETA on an iOS app?

Should I downgrade the firmware? Will that work? Any idea to what version? I use that app!
Title: Re: EEVBlog 121GW Discussion thread
Post by: Iagash on March 29, 2018, 07:30:57 am
Should I downgrade the firmware? Will that work? Any idea to what version? I use that app!

Anything < 1.10 should work, so I'd say use 1.07.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on March 29, 2018, 01:54:11 pm
I updated the meter to 1.10 and now the iphone app doesn't work. it connects (apparently) but there is no meter display in the app.
Any ideas? Fixes? Any idea when a real eevblog iOS app will be released?

The Bluetooth packet changed as has been discussed on here.
We (EEVblog "we", not UEi) do not endorse nor have control over the UEi application that is currently on the iPhone store. We are not aware of if or when they are updating that.
David is starting working on the iPhone version shortly, we now have a mac setup to enable the compiler to do this.
Title: Re: EEVBlog 121GW Discussion thread
Post by: plexus on March 29, 2018, 02:15:27 pm
I updated the meter to 1.10 and now the iphone app doesn't work. it connects (apparently) but there is no meter display in the app.
Any ideas? Fixes? Any idea when a real eevblog iOS app will be released?

The Bluetooth packet changed as has been discussed on here.
We (EEVblog "we", not UEi) do not endorse nor have control over the UEi application that is currently on the iPhone store. We are not aware of if or when they are updating that.
David is starting working on the iPhone version shortly, we now have a mac setup to enable the compiler to do this.

Thanks Dave that's good news. Looking forward to a spiffy iOS app.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on March 29, 2018, 03:56:22 pm
Thanks Dave that's good news. Looking forward to a spiffy iOS app.

In theory it's as easy as pressing Compile for iOS, but we have not done this before, so  :-//
Title: Re: EEVBlog 121GW Discussion thread
Post by: plexus on March 29, 2018, 04:01:26 pm
Thanks Dave that's good news. Looking forward to a spiffy iOS app.

In theory it's as easy as pressing Compile for iOS, but we have not done this before, so  :-//

It's probably a good time to get into iOS if not just for the experience of it. Like it or not it is a significant market and it's likely a good iOS app will inspire meter sales. But remember, iOS users are used to a particular look and feel. Don't go all Android-y/Windoze on us.  :scared: :scared: :scared:
Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on March 29, 2018, 05:24:57 pm
But remember, iOS users are used to a particular look and feel.

Sleek, stylish, streamlined - and it sets the parameters and tells the user what to do, because it knows best.
Title: Re: EEVBlog 121GW Discussion thread
Post by: plexus on March 29, 2018, 05:35:44 pm
But remember, iOS users are used to a particular look and feel.

Sleek, stylish, streamlined - and it sets the parameters and tells the user what to do, because it knows best.

That's pretty much true of Apple.

But I think there is enough flexibility with the iOS UX framework that a flexible app could be designed.
Title: Re: EEVBlog 121GW Discussion thread
Post by: kory on March 29, 2018, 08:20:15 pm
Dave thanks for the last update on these meters.  Since some people have cancelled and the meters have already been ordered, would it be possible to order more meters?

Also, it is well worth the wait for the bugs to be worked out, especially any hardware bugs.

Take care everyone!
Title: Re: EEVBlog 121GW Discussion thread
Post by: firstcolle on March 29, 2018, 08:25:29 pm
Really really looking forward to get mine :)

thanks for all your work (Dave and all the forum users that helped to find, solve and test bugs!)
Title: About changing the shipping address
Post by: VinzC on March 29, 2018, 08:56:47 pm
Hi Dave.

The survey link you posted in the Kickstarter comments section (Johnny B. Goode @ https://www.kickstarter.com/projects/eevblog/eevblog-121gw-multimeter/rewards/6297526/survey (https://www.kickstarter.com/projects/eevblog/eevblog-121gw-multimeter/rewards/6297526/survey)) to change the shipping address indeed doesn't work for me; it drives me back to kickstarter home page.

@all,

EDIT: No taking the audience for dummies, this is only for the sake of completeness.

I had to use the button «Show my contribution» (translated from French: «Afficher mon engagement»). That button stands to the right of «You are a contributor» and is visible once logged in and you're viewing the multimeter project. Then select the Survey tab. From there you can change your shipping address :-+ .

Otherwise use the kickstarter menu under your login icon on the top right corner of the page, click the EEVBlog multimeter and from there «Show my contribution».

Thanks for the update. I'm still looking forward to the postman knocking at my door ;-) .

 \$\Omega\$ sweet  \$\Omega\$ 8)
Title: Re: EEVBlog 121GW Discussion thread
Post by: Cliff Matthews on March 29, 2018, 10:43:19 pm
..a good iOS app will inspire meter sales.
Today's headlines: "Thousands of seniors and trendy spoon-fed millennials suddenly adopt electronics as a hobby"  :-DD
Title: Re: EEVBlog 121GW Discussion thread
Post by: Iagash on March 30, 2018, 02:37:44 am
At the moment raw packet logging is not a feature of the app, I use debug outputs (in visual studio, with debug mode) to get the data.

I would still suggest you include the feature in your app.

It might be the linux bluetooth stack that is the reason for the errors, but it might also be some electrical problem with pullup/diode level shifter (R76/D4 in the schematic) in my (or others) meter. Maybe the resulting voltages are too narrowly specified.

With that feature more people could check easily if that's the case on more meters.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Elasia on March 30, 2018, 02:52:27 am
At the moment raw packet logging is not a feature of the app, I use debug outputs (in visual studio, with debug mode) to get the data.

I would still suggest you include the feature in your app.

It might be the linux bluetooth stack that is the reason for the errors, but it might also be some electrical problem with pullup/diode level shifter (R76/D4 in the schematic) in my (or others) meter. Maybe the resulting voltages are too narrowly specified.

With that feature more people could check easily if that's the case on more meters.

+1 for raw packet logging / debugging, it really comes in handy to eliminate possible failure modes when making protocols
Title: Re: EEVBlog 121GW Discussion thread
Post by: Candid on March 30, 2018, 07:45:05 am
I re-checked with 1.10 and get the same results. Can someone confirm my measurements?
Why is the 121GW reading wrong in auto range/manual 5V range in this situation?

Can you reproduce the following measurements?
2.0V peak to peak sine wave 4kHz, No DC offset, duty cycle 50%. Both meters in AC mode. Firmware 1.07 on my 121GW with serial number EEVblog 000084

Auto mode on both meters, Fluke in highres mode:
121GW selects 5V range, reads 1.1133Vac
Fluke 28II selects 6V range, reads 0.7031Vac

manual mode on both meters:
121GW 5V range, reads 1.1133Vac
Fluke 28II 6V range, 0.7032Vac

121GW 50V range, reads 0.659Vac (and it looses the frequency measurement and displays 0.00kHz)
Fluke 28II 60V range, reads 0.663Vac

See the attached pictures.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Messtechniker on March 30, 2018, 10:10:44 pm
Since the 121GW seems to have an UART, I'd like to know precisely
where to get at the UART signals.
Are these at Pin 122 on U4 for Rx and Pin 119 for Tx?
Title: Re: EEVBlog 121GW Discussion thread
Post by: darrellg on March 31, 2018, 04:48:54 am
Since the 121GW seems to have an UART, I'd like to know precisely
where to get at the UART signals.
Are these at Pin 122 on U4 for Rx and Pin 119 for Tx?

There is a schematic on the product page at https://www.eevblog.com/product/121gw/ (https://www.eevblog.com/product/121gw/).
Title: Re: EEVBlog 121GW Discussion thread
Post by: fanOfeeDIY on April 02, 2018, 11:16:14 pm
Finally conduct updating the firmware of my 121GW multimeter.

I am happy with the autorange speed.

https://youtu.be/6Y1KzSA-BUE
Title: Re: EEVBlog 121GW Discussion thread
Post by: fanOfeeDIY on April 03, 2018, 02:05:37 am
Finally conduct updating the firmware of my 121GW multimeter.

I am happy with the autorange speed.

https://youtu.be/6Y1KzSA-BUE

I think I need to get better of improving video quality.
Title: Re: EEVBlog 121GW Discussion thread
Post by: coromonadalix on April 03, 2018, 07:41:52 am
nice to see improvements like this :)

now Dave  design an bench meter version loll
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on April 03, 2018, 09:48:27 am
Dave thanks for the last update on these meters.  Since some people have cancelled and the meters have already been ordered, would it be possible to order more meters?

Sorry, but no, not at this stage.
Title: Re: EEVBlog 121GW Discussion thread
Post by: JustMeHere on April 03, 2018, 10:19:22 am
Oh can't wait. Need a new DMM.
Title: Re: EEVBlog 121GW Discussion thread
Post by: carpin on April 03, 2018, 10:51:06 am
Oh can't wait. Need a new DMM.

Multimeter spreadsheet (38 brands and 210 meters listed
https://www.eevblog.com/forum/testgear/multimeter-spreadsheet/ (https://www.eevblog.com/forum/testgear/multimeter-spreadsheet/)
Title: Re: EEVBlog 121GW Discussion thread
Post by: lowimpedance on April 03, 2018, 11:18:31 am
I re-checked with 1.10 and get the same results. Can someone confirm my measurements?
Why is the 121GW reading wrong in auto range/manual 5V range in this situation?

Can you reproduce the following measurements?
2.0V peak to peak sine wave 4kHz, No DC offset, duty cycle 50%. Both meters in AC mode. Firmware 1.07 on my 121GW with serial number EEVblog 000084

Auto mode on both meters, Fluke in highres mode:
121GW selects 5V range, reads 1.1133Vac
Fluke 28II selects 6V range, reads 0.7031Vac

manual mode on both meters:
121GW 5V range, reads 1.1133Vac
Fluke 28II 6V range, 0.7032Vac

121GW 50V range, reads 0.659Vac (and it looses the frequency measurement and displays 0.00kHz)
Fluke 28II 60V range, reads 0.663Vac

See the attached pictures.

 Conducted similar measurements and can confirm similar results with regard to the frequency display. I will post the results in the 121GW issues thread where it is more appropriate.
EDIT decided to post the results here after doing some more testing and I think its not actually any bugs as such and just more like the characteristics of the meter front end.
anyway test results below........

 Ok further to Candid's test I conducted a similar test of the AC range and secondary frequency display reading.
Results for: 2V p-p 4 kHz sine wave input (terminated into 50 \$\Omega\$.). My 121GW with firmware rev 1.10.
Other meters used in comparison where Fluke 87V and Fluke 8840a

Meters in Auto ranging.
121GW reads 0.7288V RMS and the secondary display show the frequency of 3.999 kHz.
Fluke 87V in hi res reads 0.7300V RMS
Fluke 8840a reads 0.7300V RMS

Meters set to manual range.
121GW on 5V
87V on 6V
8840 on 2V
All display the same as above as expected.

Meters set to next range up.
121GW on 50V,  The voltage reading starts at 0.701V RMS for around 3 to 5 seconds then drops to 0.682V RMS and at which point the secondary frequency display goes to all zeros.
Fluke 87V on 60V, reads 0.690V RMS.
Fluke 8840a on 20V reads 0.7299V RMS and on 200V range reads 0.720V RMS.

additional measurement on the 121GW 500V range reads 0.47V RMS at both 4 kHz and 500 Hz (secondary frequency display is at 0), just for fun  :P.

NB * Further measurements of the frequency reading display show that it has a threshold of just over ~1.1 V before the secondary display starts to read frequency correctly when manual ranging to the 50V range.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Seppy on April 03, 2018, 11:58:06 am
I re-checked with 1.10 and get the same results. Can someone confirm my measurements?
Why is the 121GW reading wrong in auto range/manual 5V range in this situation?

Can you reproduce the following measurements?
2.0V peak to peak sine wave 4kHz, No DC offset, duty cycle 50%. Both meters in AC mode. Firmware 1.07 on my 121GW with serial number EEVblog 000084

Auto mode on both meters, Fluke in highres mode:
121GW selects 5V range, reads 1.1133Vac
Fluke 28II selects 6V range, reads 0.7031Vac

manual mode on both meters:
121GW 5V range, reads 1.1133Vac
Fluke 28II 6V range, 0.7032Vac

121GW 50V range, reads 0.659Vac (and it looses the frequency measurement and displays 0.00kHz)
Fluke 28II 60V range, reads 0.663Vac

See the attached pictures.

Regarding the 50V range the loss of the frequency measurement is expected, it is the wrong range for that reading and the threshold doesn't kick in for that range as it is higher.
The 5V range does appear wrong on your meter but we haven't been able to reproduce it, it could be an issue with your unit in that range.
Can you confirm that the Hz range functions correctly on your meter?

Can you also test the same range with 400Hz?
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on April 03, 2018, 10:09:05 pm
With regards to the requested 500V/5A (250VA) VA power mode. It is possible to add this (with some sacrifice in other ranges), and we have tested a solution.
But now I'm I am wondering whether or not it's actually worthwhile?
After all the meter is only capable of measuring VA and not true Watts, as the chipset does not have the phase measurement capability.
With this in mind, how useful is VA measurement in AC mode to people without a true Watts capability?
Note, that adding AC VA ranges drastically increases the number of factory calibration points required for every range added, and we are trying to minimise these ranges were possible.

SNAP POLL:
1) Should the 500V AC VA mode be added at the expense of a few of the other lower ranges?
2) Is AC VA mode even useful to people? (obviously the DC VA mode is)
Title: Re: EEVBlog 121GW Discussion thread
Post by: Fungus on April 03, 2018, 10:11:17 pm
No.

PS: What would be the "sacrifices in other ranges"?
Title: Re: EEVBlog 121GW Discussion thread
Post by: HKJ on April 03, 2018, 10:17:08 pm
1) Should the 500V AC VA mode be added at the expense of a few of the other lower ranges?
2) Is AC VA mode even useful to people? (obviously the DC VA mode is)

1) I believe this meter is for electronic, i.e. it needs the lower ranges.
2) I do not see the point in AC VA modes, I want real Watt.

The reason I bought the meter was the low burden voltage and the high diode test voltage, but if I start using it generally it will be for electronic.
Title: Re: EEVBlog 121GW Discussion thread
Post by: IanB on April 03, 2018, 11:40:07 pm
1) Should the 500V AC VA mode be added at the expense of a few of the other lower ranges?
2) Is AC VA mode even useful to people? (obviously the DC VA mode is)

No. This is an electronics meter. There are more dedicated tools available for AC power measurements that can also do Watts and power factor. It is not worth sacrificing lower ranges for this.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on April 04, 2018, 12:36:28 am
Sorry for the confusion.
I was talking about the 500V range at lower currents.
i.e. We plan to add only a 500V/10A range, not 500V/uA/mA ranges as well, that would add far too extra many factory calibration points.
We are having accuracy problems with the 500V/10A AC VA mode at the more outside edges of the voltage and current values, they are not sure if they can fix this.
I'm now asking if it's worthwhile having the 500V/10A AC VA range at all? I can't personally, but I'm not really an AC industry guy.
Title: Re: EEVBlog 121GW Discussion thread
Post by: imk on April 04, 2018, 01:13:33 am
Hello,
As don't have the 121GW yet was wondering before ordering if the PC Gui logging software will work with one of these please:
https://www.overclockers.co.uk/asus-usb-bt400-bluetooth-4.0-usb-adaptor-nw-076-as.html (https://www.overclockers.co.uk/asus-usb-bt400-bluetooth-4.0-usb-adaptor-nw-076-as.html)
Many thanks
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on April 04, 2018, 01:14:27 am
Hello,
As don't have the 121GW yet was wondering before ordering if the PC Gui logging software will work with one of these please:
https://www.overclockers.co.uk/asus-usb-bt400-bluetooth-4.0-usb-adaptor-nw-076-as.html (https://www.overclockers.co.uk/asus-usb-bt400-bluetooth-4.0-usb-adaptor-nw-076-as.html)
Many thanks

Any 4.0 adapter that supports BLE mode should work.
Title: Re: EEVBlog 121GW Discussion thread
Post by: imk on April 04, 2018, 01:37:07 am
Hello,
As don't have the 121GW yet was wondering before ordering if the PC Gui logging software will work with one of these please:
https://www.overclockers.co.uk/asus-usb-bt400-bluetooth-4.0-usb-adaptor-nw-076-as.html (https://www.overclockers.co.uk/asus-usb-bt400-bluetooth-4.0-usb-adaptor-nw-076-as.html)
Many thanks

Any 4.0 adapter that supports BLE mode should work.

Hello Dave and many thanks for the prompt reply.
So i have been driving me-self nuts trying to find a new MM for a week now and think this really fit my needs.
Only thing i would change if possible would be the ability to remove/swap  the micro sd card without taking the back off, a little hatch would be great and well if you do consider it, it could i guess a retro fit back for those lucky people that already have one.
BTW i have contacted Welectron re when they may have some but was wondering if you had a waiting customer list i could be added to please, i can pm you my email if you wish?
Again many thanks imk
Title: Re: EEVBlog 121GW Discussion thread
Post by: imk on April 04, 2018, 02:00:03 am
1) Should the 500V AC VA mode be added at the expense of a few of the other lower ranges?
2) Is AC VA mode even useful to people? (obviously the DC VA mode is)

1. My needs are electronic so no need for 500v ac
2. Would AC VA (Watts) be useful for audio amplifier output power measurements? if so then maybe useful to me.
Title: Re: EEVBlog 121GW Discussion thread
Post by: IanB on April 04, 2018, 02:08:30 am
I'm now asking if it's worthwhile having the 500V/10A AC VA range at all? I can't personally, but I'm not really an AC industry guy.

This is how I understood the question, and how I answered it. It doesn't seem worth sacrificing other capabilities for this.
Title: Re: EEVBlog 121GW Discussion thread
Post by: bicycleguy on April 04, 2018, 04:04:11 am
With regards to the requested 500V/5A (250VA) VA power mode.
Is that 2500VA?
It is possible to add this (with some sacrifice in other ranges), and we have tested a solution.
What is the sacrifice exactly?  Isn't the next range down 500mVAC.
But now I'm I am wondering whether or not it's actually worthwhile?
After all the meter is only capable of measuring VA and not true Watts, as the chipset does not have the phase measurement capability.
With this in mind, how useful is VA measurement in AC mode to people without a true Watts capability?
Doe's this mean Joe noob (ie me) looking around for things to measure won't be able to look at all my energy wasting 110VAC stuff.  I think my new fangled utility meter bills me measuring only VA? 
Title: Re: EEVBlog 121GW Discussion thread
Post by: HKJ on April 04, 2018, 04:07:21 am
Doe's this mean Joe noob (ie me) looking around for things to measure won't be able to look at all my energy wasting 110VAC stuff.  I think my new fangled utility meter bills me measuring only VA?

Usual it is Watt the utility meters are measuring. VA is just current multiplied by voltage, i.e. you can get a very good estimate of VA by measuring the current and multiply by 120.
Title: Re: EEVBlog 121GW Discussion thread
Post by: IanB on April 04, 2018, 04:23:58 am
Doe's this mean Joe noob (ie me) looking around for things to measure won't be able to look at all my energy wasting 110VAC stuff.  I think my new fangled utility meter bills me measuring only VA?

You are better using a Kill-A-Watt (original, or one of the many clones) device for this application. It will report both true power and power factor, and will have a built-in totalizing feature. It is also much safer to plug into a power socket without dangling wires or test leads.

Your utility meter measures actual power and you get charged for actual power. You do not get charged for VA.
Title: Re: EEVBlog 121GW Discussion thread
Post by: 1anX on April 04, 2018, 08:15:56 am
I bought the meter for electronics and like others have indicated the low burden voltage and higher zener test voltages appealed to me.
I have other meters for mains AC voltages and currents!
Title: Re: EEVBlog 121GW Discussion thread
Post by: Candid on April 04, 2018, 08:26:42 am
The 5V range does appear wrong on your meter but we haven't been able to reproduce it, it could be an issue with your unit in that range.
Can you confirm that the Hz range functions correctly on your meter?

Can you also test the same range with 400Hz?
HZ range functions well up to about 720kHz in the Hz mode, and up to 680kHz in V mode on the second display (with a sine 2Vpp).

I tested with 400Hz sine 2Vpp and get the same wrong voltage measurement at 5Vac (auto) range mode (1,1xxx Vrms). 50Vac manual mode gives me again the correct measurement.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on April 04, 2018, 09:20:22 am
Is that 2500VA?

5000VA actually, 10A capable.

Quote
What is the sacrifice exactly?  Isn't the next range down 500mVAC.

The next range down is 500VA, but it's a 50V range, not 500V, that's what I'm saying, there is only one 500V range and that is 10A.

Quote
Doe's this mean Joe noob (ie me) looking around for things to measure won't be able to look at all my energy wasting 110VAC stuff.  I think my new fangled utility meter bills me measuring only VA?

You should not be using a multimeter like this for your appliances, just but a cheap Kill-A-Watt unit that measures proper W and VA power.
Most utilities will charge in W, not VA for residential customers, but that varies depending upon the country and utility company.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Cliff Matthews on April 04, 2018, 10:20:07 am
This $11 inductive meter (https://www.banggood.com/100A-Power-Monitor-Module-AC-Meter-Panel-p-983057.html?cur_warehouse=CN) can be handy enclosed on the receptacle end of a DIY extension cord. Here it is in action (https://youtu.be/ZL7WTpRMNwE).
Title: Re: EEVBlog 121GW Discussion thread
Post by: Elasia on April 04, 2018, 12:28:41 pm
AC fruit cake checking in

I also say no, there are more purpose built devices for this on both the low end as above and high end as well like this http://en-us.fluke.com/products/power-quality-analyzers/fluke-345-clamp-meter.html (http://en-us.fluke.com/products/power-quality-analyzers/fluke-345-clamp-meter.html) i got at work.

Or can even be made quickly and cheap but who does that when China does it for you these days

As others already said, i think the world of a good electronics meter built for that purpose.. dont spoil the goods trying to be good at to many different things.
Title: Re: EEVBlog 121GW Discussion thread
Post by: geekGee on April 04, 2018, 01:08:39 pm
The meter is EEVBlog branded and I believe the first "E" stands for "electronics".  ;D

That's why I ordered one anyway.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Seppy on April 04, 2018, 01:40:52 pm

I was thinking of the spurious VA values. We no longer get these as it's been (as far as we can tell) fixed in software. So if spurious values are being seen, maybe that's a possible cause?
But if it's a checksum thing, then forget I said it.
But as I believe David (seppy) has said, we are no longer getting corrupted data, and hence no more checksum errors.

How could the range switch cause invalid xor checksums?

I don't see spurious VA values as in the early versions of the firmware.

With V1.10 I still see wrong voltage and current displays in certain parts of the measuring range, I see a spurious wrong decimal point in current display and I see wrong range display (A instead of mA) in the current display. All of this in DC VA-mode.

Apart from that the displayed values are consistently wrong.

I guess the invalid checksums must then be some electrical problem in my meter if no one else can see them.

As there seems no way to debug it further, I can't help you there.

Update has been released to the app stores, likely hasn't updated on both yet but these issues should all be resolved now, we also have a new firmware version which will be resolving one of the other issues (when the voltage in VA mode is above 32767 approximately, this firmware update hasn't been released, this issue was a packet issue not a app issue so for those values you'll need to wait for the next firmware update).
Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on April 04, 2018, 02:33:17 pm
Only thing i would change if possible would be the ability to remove/swap  the micro sd card without taking the back off, a little hatch would be great and well if you do consider it

This has been mentioned before - but I believe the issue is one of safety.  The Cat ratings and safety design of the 121GW is based on the only access to the meter's circuitry being through the probe sockets on the front - which have been designed to certain standards.

To access the microSD card, you would be given access to the microSD card slot - which is connected to the meter's innards.  Such an interface would need very special consideration to be suitably rated - if, indeed, that were at all possible.  Since the microSD facility was a "fit in", the restriction on access in order to maintain safety and the Cat ratings is one that will (as I understand it) have to stand.

Using the Bluetooth facility is probably going to be a better bet for the sort of things I suspect you are contemplating.
Title: Re: EEVBlog 121GW Discussion thread
Post by: 1anX on April 06, 2018, 08:34:58 am
Hey Dave, should I start checking my letterbox anytime soon for a delivery?
It must be getting very close by now for the Johnny B Goode shipment to be shipped.
Looking forward to playing with this meter sometime very soon  :-+
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on April 06, 2018, 08:54:43 am
Only thing i would change if possible would be the ability to remove/swap  the micro sd card without taking the back off, a little hatch would be great and well if you do consider it

This has been mentioned before - but I believe the issue is one of safety.  The Cat ratings and safety design of the 121GW is based on the only access to the meter's circuitry being through the probe sockets on the front - which have been designed to certain standards.

To access the microSD card, you would be given access to the microSD card slot - which is connected to the meter's innards.  Such an interface would need very special consideration to be suitably rated - if, indeed, that were at all possible.  Since the microSD facility was a "fit in", the restriction on access in order to maintain safety and the Cat ratings is one that will (as I understand it) have to stand.

Yes, it's an issue of access safety.
I know it's a bit of a PITA, but it takes under 20 seconds to remove the boot, unscrew the cover and remove the SD card and insert into computer.
If you need more accessible data logging then I'd recommend a proper data logger. This is a multimeter first with some SD logging capability, not the other way around.
I guess you could always dremel a slot in the back perhaps?
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on April 06, 2018, 09:16:13 am
Hey Dave, should I start checking my letterbox anytime soon for a delivery?
It must be getting very close by now for the Johnny B Goode shipment to be shipped.
Looking forward to playing with this meter sometime very soon  :-+

The rest of the Great Scott backer will be shipped first.
We are close to a release solution, just dealing with a few last minute things, that's my job this morning.
Title: Re: EEVBlog 121GW Discussion thread
Post by: IanB on April 06, 2018, 09:19:30 am
Yes, it's an issue of access safety.
I know it's a bit of a PITA, but it takes under 20 seconds to remove the boot, unscrew the cover and remove the SD card and insert into computer.
If you need more accessible data logging then I'd recommend a proper data logger. This is a multimeter first with some SD logging capability, not the other way around.
I guess you could always dremel a slot in the back perhaps?

I would have imagined trying to have the SD card slot under the battery cover rather than having to open the whole meter to access it...?
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on April 06, 2018, 10:04:17 am
I would have imagined trying to have the SD card slot under the battery cover rather than having to open the whole meter to access it...?

The SD card is under the battery cover (with machine screws, so won't wear out), but like many meters you have to remove the rubber boot to access the battery compartment.
I've timed it, it took me less than 20 seconds to access.
Title: Re: EEVBlog 121GW Discussion thread
Post by: VEGETA on April 06, 2018, 12:47:38 pm
Why don't you make the SD card slot from the side like laptops? just a hole\slot in the side of the multimeter and it will be perfect. The holster will hide and protect it.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Cliff Matthews on April 06, 2018, 01:25:27 pm
Why don't you make the SD card slot from the side like laptops? just a hole\slot in the side of the multimeter and it will be perfect. The holster will hide and protect it.
But it's not in the same compliance category as a laptop, so it wouldn't have passed standards testing.
(EC 60950 talks about "Emission of flame or expulsion of molten metal")
Title: Re: EEVBlog 121GW Discussion thread
Post by: bitwelder on April 06, 2018, 03:22:57 pm
I guess you could always dremel a slot in the back perhaps?
:scared:

Would one of those WiFi-enabled SD cards work?
Title: Re: EEVBlog 121GW Discussion thread
Post by: mtdoc on April 06, 2018, 03:34:42 pm
Why don't you make the SD card slot from the side like laptops? just a hole\slot in the side of the multimeter and it will be perfect. The holster will hide and protect it.
But it's not in the same compliance category as a laptop, so it wouldn't have passed standards testing.
(EC 60950 talks about "Emission of flame or expulsion of molten metal")

IIRC the Mooshimeter had the same issue with testing and its SD card slot and also opted for a slot that required opening the case to access.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on April 06, 2018, 03:50:14 pm
I guess you could always dremel a slot in the back perhaps?
:scared:

Would one of those WiFi-enabled SD cards work?

It's micro SD, do they even make those?
And no idea if it would work.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Mr.B on April 06, 2018, 04:56:43 pm
IIRC the Mooshimeter had the same issue with testing and its SD card slot and also opted for a slot that required opening the case to access.

Correct.
The one I have has thinner indented plastic molding where the slot was in the original design.
The guy who designed the meter had to change the injection mold to comply with the required safety standards.
However, the end user can easily snap out the plastic to make a slot if they wish - at their own risk of course.
Title: Re: EEVBlog 121GW Discussion thread
Post by: mtdoc on April 06, 2018, 10:20:51 pm
IIRC the Mooshimeter had the same issue with testing and its SD card slot and also opted for a slot that required opening the case to access.

Correct.
The one I have has thinner indented plastic molding where the slot was in the original design.
The guy who designed the meter had to change the injection mold to comply with the required safety standards.
However, the end user can easily snap out the plastic to make a slot if they wish - at their own risk of course.

Yep. James had to change it. The result was something that passes testing but can be easily modified for easier SD card access.

I don’t know if something similar could have been done with the 121GW - maybe not since a large OEM is involved. But I agree with Dave that it’s not that hard to get to the SD slot in any case.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on April 06, 2018, 10:25:00 pm
I don’t know if something similar could have been done with the 121GW

It wasn't. The SD card was added after the case molds had been made.
Title: Re: EEVBlog 121GW Discussion thread
Post by: imk on April 06, 2018, 11:08:19 pm
Oh Dave, i wonder if this SD issues is getting more attention than it deserves?

I  need (not urgently) a new multimeter as my main one is on the blink so thought i'd treat myself to a nice new one as landmark birthday coming up.
Friend wants me to do some battery performance comparisons plus i want to do some solar cell output checks so data logging via MM seems the way to go.
Bust my brain for a week going around the reviews/shops looking for what I thought  i wanted which was a wired solution (RS232/USB).
Then a moment of clarity dawned, a MM with 4xAA built in recording/logging at a price the fits my needs+budget equation that doesn't need wires WOW!
Much searching reveals one solution the 121GW, Dave when can i have one please?

I only mentioned the SD hatch as possible scenario "Can't find my USB dongle and Bugger I need to go to workshop for Screwdriver.
Please forget i ever mentioned it and if there's anything i can do to help you get the 121GW in the shops just ask as i'm retired and have time to help good projects like this :-)
Plus lots of C/C++ PC and embedded/PIC coding miles.
 
Ian
 
Title: Re: EEVBlog 121GW Discussion thread
Post by: VEGETA on April 07, 2018, 12:19:33 am
I wonder about something... Why don't mutlimeters come with rechargeable batteries such as Li-ion\Li-Po? with capability to charge it with micro USB plug.

I suspect that it won't pass tests for safety or so, but I need the correct answer.
Title: Re: EEVBlog 121GW Discussion thread
Post by: IanB on April 07, 2018, 12:29:12 am
I wonder about something... Why don't mutlimeters come with rechargeable batteries such as Li-ion\Li-Po? with capability to charge it with micro USB plug.

I suspect that it won't pass tests for safety or so, but I need the correct answer.

1) Most multimeters use so little power that rechargeable batteries are unnecessary
2) If you want to use rechargeable batteries with an external charger there is nothing to stop you
3) With a built-in rechargeable battery you are left unable to use the meter while the batteries are recharging, making this an inconvenient solution
Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on April 07, 2018, 01:38:23 am
 4) Access for charging internal batteries would compromise safety - just as having external access to the internal microSD card would be on the 121GW
Title: Re: EEVBlog 121GW Discussion thread
Post by: HKJ on April 07, 2018, 01:53:10 am
4) Access for charging internal batteries would compromise safety - just as having external access to the internal microSD card would be on the 121GW

It is possible to work around that (A safety rated DC/DC converter).
Title: Re: EEVBlog 121GW Discussion thread
Post by: imk on April 07, 2018, 02:08:07 am
I wonder about something... Why don't mutlimeters come with rechargeable batteries such as Li-ion\Li-Po? with capability to charge it with micro USB plug.

I suspect that it won't pass tests for safety or so, but I need the correct answer.

Guess this is how you get around the safety issues of rechargeable MM
https://www.alibaba.com/product-detail/Rechargeable-Self-Restoring-LCD-Digital-Multimeter_60366637118.html?spm=a2700.7724857.main07.8.198777e4cV0KF7 (https://www.alibaba.com/product-detail/Rechargeable-Self-Restoring-LCD-Digital-Multimeter_60366637118.html?spm=a2700.7724857.main07.8.198777e4cV0KF7)
Title: Re: EEVBlog 121GW Discussion thread
Post by: VEGETA on April 07, 2018, 02:16:54 am
4) Access for charging internal batteries would compromise safety - just as having external access to the internal microSD card would be on the 121GW

I think it is just an over concern. I don't think that there is anything bad gonna happen since we have tons of products with Li-ion batteries and are safe, same for SD card issue. But this is just my humble opinion... If there is an affordable good meter like 121gw but with rechargeable battery, I would buy it.

 
Quote
Guess this is how you get around the safety issues of rechargeable MM
https://www.alibaba.com/product-detail/Rechargeable-Self-Restoring-LCD-Digital-Multimeter_60366637118.html?spm=a2700.7724857.main07.8.198777e4cV0KF7 (https://www.alibaba.com/product-detail/Rechargeable-Self-Restoring-LCD-Digital-Multimeter_60366637118.html?spm=a2700.7724857.main07.8.198777e4cV0KF7)

LOL... WTF! this is very nice although being stupid!

perfect workaround  :-DD :-DD :-DD Safety my ***

These probably followed ElectroBOOM advice: "Safety always comes second priority"
Title: Re: EEVBlog 121GW Discussion thread
Post by: HKJ on April 07, 2018, 02:17:35 am
Guess this is how you get around the safety issues of rechargeable MM
https://www.alibaba.com/product-detail/Rechargeable-Self-Restoring-LCD-Digital-Multimeter_60366637118.html?spm=a2700.7724857.main07.8.198777e4cV0KF7 (https://www.alibaba.com/product-detail/Rechargeable-Self-Restoring-LCD-Digital-Multimeter_60366637118.html?spm=a2700.7724857.main07.8.198777e4cV0KF7)

Keysight has one DMM where you apply 24VDC to the probe input to charge, this means you have a huge external power supply.
I do not really know what I like best of these two solution.
Title: Re: EEVBlog 121GW Discussion thread
Post by: IanB on April 07, 2018, 02:37:45 am
If there is an affordable good meter like 121gw but with rechargeable battery, I would buy it.

Why would you buy it? What problem does it solve for you?
Title: Re: EEVBlog 121GW Discussion thread
Post by: ez24 on April 07, 2018, 04:25:44 am

Guess this is how you get around the safety issues of rechargeable MM
https://www.alibaba.com/product-detail/Rechargeable-Self-Restoring-LCD-Digital-Multimeter_60366637118.html?spm=a2700.7724857.main07.8.198777e4cV0KF7 (https://www.alibaba.com/product-detail/Rechargeable-Self-Restoring-LCD-Digital-Multimeter_60366637118.html?spm=a2700.7724857.main07.8.198777e4cV0KF7)

This meter has something I like : polyfuses

Why don't other meters use them?

Title: Re: EEVBlog 121GW Discussion thread
Post by: HKJ on April 07, 2018, 04:34:16 am
This meter has something I like : polyfuses

Why don't other meters use them?

One reason may be burden voltage, they have higher on resistance than fuses (At least the ones I have seen in multimeters).

They can probably not match a high quality fuse in safety either.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Cliff Matthews on April 07, 2018, 04:37:48 am
DMM front-end design factors-in known resistance of fuses that recover well. Sadly, polyfuses may some undesirable specs.
Title: Re: EEVBlog 121GW Discussion thread
Post by: bitwelder on April 07, 2018, 05:19:14 am
Would some kind of inductive powering (like Qi charging) feasible in a safe way in a meter, if the receiving antenna is e.g. well inside the body of the instrument, like the battery compartment?
Title: Re: EEVBlog 121GW Discussion thread
Post by: IanB on April 07, 2018, 06:38:08 am
Would some kind of inductive powering (like Qi charging) feasible in a safe way in a meter, if the receiving antenna is e.g. well inside the body of the instrument, like the battery compartment?

Again, it adds complexity and cost, to what purpose? What is the point?

Cell phones get charged every few days, so convenient recharging is relevant.

Multimeters get recharged every few months, maybe once a year. So what problem does a built-in rechargeable battery solve?
Title: Re: EEVBlog 121GW Discussion thread
Post by: tautech on April 07, 2018, 08:29:05 am
Would some kind of inductive powering (like Qi charging) feasible in a safe way in a meter, if the receiving antenna is e.g. well inside the body of the instrument, like the battery compartment?

Again, it adds complexity and cost, to what purpose? What is the point?

Cell phones get charged every few days, so convenient recharging is relevant.

Multimeters get recharged every few months, maybe once a year. So what problem does a built-in rechargeable battery solve?
Overall size and weight especially with lithium ion.

Joe Smith did some DMM logging tests with Bluetooth and it certainly can chew up batteries whereas if a DMM was logging while parked in an inductive charging cradle long term battery live would no longer be part of the picture.

Dave might like to think about a R2 version implementing these sorts of design features.
Title: Re: EEVBlog 121GW Discussion thread
Post by: IanB on April 07, 2018, 08:49:36 am
Joe Smith did some DMM logging tests with Bluetooth and it certainly can chew up batteries whereas if a DMM was logging while parked in an inductive charging cradle long term battery live would no longer be part of the picture.

That's true, but...I am forced to wonder if a combination of "sensitive measuring instrument" and "externally imposed inductive field" would be a good idea?

I am inclined to suspect it would be a shielding nightmare.
Title: Re: EEVBlog 121GW Discussion thread
Post by: IanB on April 07, 2018, 08:52:22 am
BTW, I have logged for hours at a time with my favorite logging meters and not had any concerns about battery drain, even though using a 9 V battery.

It's probably not the logging that's expensive, but the Bluetooth.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on April 07, 2018, 09:29:07 am
Would some kind of inductive powering (like Qi charging) feasible in a safe way in a meter, if the receiving antenna is e.g. well inside the body of the instrument, like the battery compartment?

No point when your meter has 500+ hours battery life, and you can change the batteries available anywhere.
Title: Re: EEVBlog 121GW Discussion thread
Post by: VEGETA on April 07, 2018, 11:06:09 am
when will 121gw meters be available again? how much total price to Jordan?

Also what is the difference in performance between it and the brymen one?
Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on April 07, 2018, 11:33:19 am
To all those who missed the point on safety I was trying to make:   :palm:

The safety concern is one where you have a breach in the isolation of the meter for a charging port.  Only this response addressed that:
Would some kind of inductive powering (like Qi charging) feasible in a safe way in a meter, if the receiving antenna is e.g. well inside the body of the instrument, like the battery compartment?


Whether any efforts along this line are worth the effort, however, is another question.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on April 07, 2018, 01:23:47 pm
After quite some R&D and testing, we have decided to drop the proposed 500V VA range support.
All the existing 50V and lower ranges will be available.
Title: Re: EEVBlog 121GW Discussion thread
Post by: imk on April 07, 2018, 04:54:50 pm
Lipo's, alkaline's, Nicad etc are all things of the past anyway.
TEN TIMES the energy density of the above and all you need is tea spoon of sugar to recharge them.
500 hr becomes 5000 hr and that's half a year of continues use, even electric car start to make sense :-)
https://vtnews.vt.edu/articles/2014/01/012213-cals-battery.html
Title: Re: EEVBlog 121GW Discussion thread
Post by: Messtechniker on April 07, 2018, 11:13:27 pm
Well, most news on this sugar battery is from 2014,
with not much thereafter.  Problems? Busted? April fools? :wtf:
Title: Re: EEVBlog 121GW Discussion thread
Post by: bitwelder on April 07, 2018, 11:43:33 pm
Would some kind of inductive powering (like Qi charging) feasible in a safe way in a meter, if the receiving antenna is e.g. well inside the body of the instrument, like the battery compartment?

No point when your meter has 500+ hours battery life, and you can change the batteries available anywhere.
I was thinking of very long datalogging sessions, and perhaps using a meter that is not so low-power to last 500+ hours.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Scottjd on April 08, 2018, 04:13:40 am
Would some kind of inductive powering (like Qi charging) feasible in a safe way in a meter, if the receiving antenna is e.g. well inside the body of the instrument, like the battery compartment?

No point when your meter has 500+ hours battery life, and you can change the batteries available anywhere.
Is this 500 hours of battery life while actively logging to an SD card and broadcasting serial Bluetooth signals? I have a logging meter, it doesn’t get any battery life like a normal one does with a single 9V.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Scottjd on April 08, 2018, 04:20:08 am
4) Access for charging internal batteries would compromise safety - just as having external access to the internal microSD card would be on the 121GW
How would access to the SD card compromise safety?
Ok, potential loop grounding issue if plugged into a computer USB port while measuring mains voltage at the same time. Or like three meters I own the simple solution is serial put data to usb via two infrared making it completely iscolated from the ground in the USB of the computer.
After all, it doesn’t need to be USB 3.1 Gen 2 sleeeds at 10Gbs data transfer, it is just little lines of text being stored. If the micro processor had a little extra code it might be able to complete one of the oldest tasks besides computers have dkne for years besides a calculator, and compress this into a zip file making it 1/100th of the original size for faster transfer speeds.

Update: I just saw the comment you made to those who missed the point. I didn’t miss it, but I do have a $20 meter in my hand that does this type of isolation made by Digitek, it’s the DT-4000ZC
if a $20 meter can do this, I’m sure the effort can be that much extra?
Title: Re: EEVBlog 121GW Discussion thread
Post by: mikeselectricstuff on April 08, 2018, 04:25:48 am
4) Access for charging internal batteries would compromise safety - just as having external access to the internal microSD card would be on the 121GW
How would access to the SD card compromise safety?
Because the DMM's 0V rail could be connected to several hundred volts
Title: Re: EEVBlog 121GW Discussion thread
Post by: Scottjd on April 08, 2018, 04:51:39 am
4) Access for charging internal batteries would compromise safety - just as having external access to the internal microSD card would be on the 121GW
How would access to the SD card compromise safety?
Because the DMM's 0V rail could be connected to several hundred volts

Ok, I know I dropped a $20 meter for an example,but the fluke 289 works the same way. The receiving IR and PCB/Chip is not connected to the main DMM PCB at all, in fact it’s powered by the 5VDC from the USB port. So forgive me if I wrong, but I still don’t see how that would be possible.
Title: Re: EEVBlog 121GW Discussion thread
Post by: IanB on April 08, 2018, 05:50:56 am
Ok, I know I dropped a $20 meter for an example,but the fluke 289 works the same way. The receiving IR and PCB/Chip is not connected to the main DMM PCB at all, in fact it’s powered by the 5VDC from the USB port. So forgive me if I wrong, but I still don’t see how that would be possible.

Because the SD card does not have onboard power like a USB port, and so the SD card driver has to be powered by the meter's internal circuitry, which means there is an electrical path between the terminals of the meter and the SD card.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Scottjd on April 08, 2018, 11:38:59 am
Ok, I know I dropped a $20 meter for an example,but the fluke 289 works the same way. The receiving IR and PCB/Chip is not connected to the main DMM PCB at all, in fact it’s powered by the 5VDC from the USB port. So forgive me if I wrong, but I still don’t see how that would be possible.

Because the SD card does not have onboard power like a USB port, and so the SD card driver has to be powered by the meter's internal circuitry, which means there is an electrical path between the terminals of the meter and the SD card.

Ok, apparently I missed the point. I thought we were talking about transferring data on the SD off the meter   different ways?
I’m over it.
Title: Re: EEVBlog 121GW Discussion thread
Post by: imk on April 09, 2018, 03:34:03 am
121GW battery life vs battery type.
As far as the 500 hr battery life claim is this for alkaline or NiCad and what mah rating
My camera packs up much earlier on nicad than on fresh alkaline as the static voltage is lower for NiCad's
Any 121GW test data for various battery chemistry yet?
Title: Re: EEVBlog 121GW Discussion thread
Post by: maukka on April 09, 2018, 06:56:11 pm
You should not be using a multimeter like this for your appliances, just but a cheap Kill-A-Watt unit that measures proper W and VA power.
Most utilities will charge in W, not VA for residential customers, but that varies depending upon the country and utility company.
I did not think the Killawatt could read very low power levels. 
But a good (for a cheap) power meter like the Zhurui PR10 (https://www.aliexpress.com/store/group/Power-Recorder/427884_509189231.html) will do fine down to 5mA at 230V. Takes 0.1 watts to display power though.

HKJ's test http://lygte-info.dk/review/Power%20Zhurui%20Power%20Recorder%20PR10%20UK.html (http://lygte-info.dk/review/Power%20Zhurui%20Power%20Recorder%20PR10%20UK.html)
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on April 09, 2018, 09:25:39 pm
121GW battery life vs battery type.
As far as the 500 hr battery life claim is this for alkaline or NiCad and what mah rating
My camera packs up much earlier on nicad than on fresh alkaline as the static voltage is lower for NiCad's
Any 121GW test data for various battery chemistry yet?

4.2V dropout voltage, approx 5mA consumption, you can do the math with whatever chemistry.
The spec is Alkaline.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on April 09, 2018, 09:29:08 pm
Is this 500 hours of battery life while actively logging to an SD card and broadcasting serial Bluetooth signals?

No, logging is lower, but don't have accurate specs for that. SD drops it to a few hundred hours IIRC. Have not tested Bluetooth, but it's BLE at a low sample rate so shouldn't take much.
Title: Re: EEVBlog 121GW Discussion thread
Post by: coromonadalix on April 10, 2018, 12:31:31 pm
would be nice to pop in something like this gadget :  http://www.icstation.com/dual-card-adapter-shield-micro-card-dual-system-switch-converter-raspberry-b2b3b-p-10868.html (http://www.icstation.com/dual-card-adapter-shield-micro-card-dual-system-switch-converter-raspberry-b2b3b-p-10868.html)

or an flexible sd card extender ???, but you have to slot the casing either way ...
Title: Re: EEVBlog 121GW Discussion thread
Post by: imk on April 10, 2018, 05:16:32 pm
Is this 500 hours of battery life while actively logging to an SD card and broadcasting serial Bluetooth signals?

No, logging is lower, but don't have accurate specs for that. SD drops it to a few hundred hours IIRC. Have not tested Bluetooth, but it's BLE at a low sample rate so shouldn't take much.

Either way this 121GW is way ahead of anything else i have found, the PeakTech 3440 only does 7hr on batteries when logging so not a solution at all.
121GW is definitely going to get best meter of the year award :-)
Title: Re: EEVBlog 121GW Discussion thread
Post by: blueskull on April 10, 2018, 05:44:31 pm
@EEVBlog Just receive a "last minute address change" notification from KS. Are the US units about to be shipped?
Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on April 10, 2018, 06:49:48 pm
Getting ready to print the shipping labels is my guess.
Title: Re: EEVBlog 121GW Discussion thread
Post by: imk on April 10, 2018, 07:02:17 pm
121GW battery life vs battery type.
As far as the 500 hr battery life claim is this for alkaline or NiCad and what mah rating
My camera packs up much earlier on nicad than on fresh alkaline as the static voltage is lower for NiCad's
Any 121GW test data for various battery chemistry yet?

4.2V dropout voltage, approx 5mA consumption, you can do the math with whatever chemistry.
The spec is Alkaline.

Well quick math looks like a 2400 mah AA NiCd down to 10% charge will still run the 121GW, so still in the region of 500 hr run time.
3200 mah Ni-MH would real push the envelope, think two sets of these would be why for me to go :-)

No mention of a supply date yet, so makes me wonder if not some under the covers magic being worked out  8)
Title: Re: EEVBlog 121GW Discussion thread
Post by: HKJ on April 10, 2018, 07:16:23 pm
3200 mah Ni-MH would real push the envelope, think two sets of these would be why for me to go :-)

3200mAh NiMH would probably not work very long, the maximum real capacity I have seen is around 2500-2700mAh, anything rated with more usual has a lot less.
Title: Re: EEVBlog 121GW Discussion thread
Post by: imk on April 12, 2018, 12:56:06 am
121GW battery life vs battery type.
As far as the 500 hr battery life claim is this for alkaline or NiCad and what mah rating
My camera packs up much earlier on nicad than on fresh alkaline as the static voltage is lower for NiCad's
Any 121GW test data for various battery chemistry yet?

4.2V dropout voltage, approx 5mA consumption, you can do the math with whatever chemistry.
The spec is Alkaline.

Well quick math looks like a 2400 mah AA NiCd down to 10% charge will still run the 121GW, so still in the region of 500 hr run time.
3200 mah Ni-MH would real push the envelope, think two sets of these would be why for me to go :-)

No mention of a supply date yet, so makes me wonder if not some under the covers magic being worked out  8)

Hello HKJ,
Like with most things these days what it says on the box is not what it does.
Imk
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on April 12, 2018, 11:05:16 am
@EEVBlog Just receive a "last minute address change" notification from KS. Are the US units about to be shipped?

Yes, we had to lock down the address changes and KS makes us wait 48hours. We actually have like 150 or something last minutes changes!
1000 units will be available end of April (as in available to ship to the various distributors, Welectron for the EU, here for Oz/NZ/others, EUi/KaneTest for the US)
and another 1000 units end of May
(so I guess their production capacity is 1000 units a month)
As before, the remainder of the Great Scott backers will be shipped first. But given that there will be a lot of leftover units from the first 1000 unit batch, many Johnny B. Goode backers will get theirs at the same time. 
Title: Re: EEVBlog 121GW Discussion thread
Post by: VEGETA on April 12, 2018, 03:21:25 pm
So when will this be available to us regular customers?

I am in Jordan, how much will it cost to be shipped to here?
Title: Re: EEVBlog 121GW Discussion thread
Post by: tomp on April 12, 2018, 03:26:42 pm
Welectron for the EU
Hi, Dave. I have also received "last minute address change" e-mail, but I have not received the PayPal VAT invoices yet. Have you sent them? I am in Johnny B. Goode group and I chose the EU shipping option. Please be so kind and post an update to Kickstarter as soon as you send the invoices, so we do not miss something.

By the way, how is the "exclusive EEVblog video of the development history of this meter"? :)
Title: Re: EEVBlog 121GW Discussion thread
Post by: imk on April 12, 2018, 08:05:40 pm
@EEVBlog Just receive a "last minute address change" notification from KS. Are the US units about to be shipped?

Yes, we had to lock down the address changes and KS makes us wait 48hours. We actually have like 150 or something last minutes changes!
1000 units will be available end of April (as in available to ship to the various distributors, Welectron for the EU, here for Oz/NZ/others, EUi/KaneTest for the US)
and another 1000 units end of May
(so I guess their production capacity is 1000 units a month)
As before, the remainder of the Great Scott backers will be shipped first. But given that there will be a lot of leftover units from the first 1000 unit batch, many Johnny B. Goode backers will get theirs at the same time.


Already got my name on one at Welectron n waiting, thanks Dave for the heads up, bit of luck be here for my milestone Bday
imk
Title: Re: EEVBlog 121GW Discussion thread
Post by: Average Meatsack on April 13, 2018, 01:38:23 pm
Bugger! Missed the email to confirm the delivery address. Will it be a signature required delivery? If not, that may cause problems since the front door of my flat faces the road and I wouldn't want it stolen.

Which courier company is handling the NZ deliveries. I just hope it isn't AusPost as my one and only experience with them was terrible.
Title: Re: EEVBlog 121GW Discussion thread
Post by: nickdepinet on April 14, 2018, 07:00:05 am
@EEVBlog Just receive a "last minute address change" notification from KS. Are the US units about to be shipped?

Yes, we had to lock down the address changes and KS makes us wait 48hours. We actually have like 150 or something last minutes changes!
1000 units will be available end of April (as in available to ship to the various distributors, Welectron for the EU, here for Oz/NZ/others, EUi/KaneTest for the US)
and another 1000 units end of May
(so I guess their production capacity is 1000 units a month)
As before, the remainder of the Great Scott backers will be shipped first. But given that there will be a lot of leftover units from the first 1000 unit batch, many Johnny B. Goode backers will get theirs at the same time.

A bit confused here - are the US Great Scott units being shipped from the fixed units from before or are they coming from this new batch being shipped at the end of April? Basically just wondering what happened to the original great scott units that made it through customs into the US before they got redirected to KaneTest.
Title: Re: EEVBlog 121GW Discussion thread
Post by: TMM on April 14, 2018, 06:01:56 pm
Would some kind of inductive powering (like Qi charging) feasible in a safe way in a meter, if the receiving antenna is e.g. well inside the body of the instrument, like the battery compartment?
The main issue is that the inductive field will couple into the analogue front end and maybe throw it out of spec - semiconductor junctions can act as rectifiers and cause an offset on the measurement. I design inductively powered devices and just measuring small signals in the presence of a HF band inductive field can be challenging at times. Unlike electric fields it's not trivial to make a device immune to HF band magnetic fields - thin metal cans do diddly squat. A better solution would just be to power it with a properly isolated DC-DC supply.
Title: How to purchase 121GW?
Post by: rpb1 on April 15, 2018, 01:24:08 am
seemingly stupid question... i must have missed something? 

how do i get into the queue for one or more of the 121GW's to be released in May?  i'm in the USA

essentially, how do i purchase?

been spinning around looking in eevblog and i cant find this info.  Found it listed in the "store" but without a means to order it - only view info.

Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on April 15, 2018, 01:34:27 am
If you haven't got your name down in the Kickstarter, you will have to wait until Dave gets them into his online shop.  Before that happens, he has to honour the outstanding Kickstarter orders.

Keep checking on his shop - but from what I've gleaned, don't expect to see anything for a month or more.
 Check back on this thread, too - as you will likely pick up on progress here.

There is no "queue" you can get on.  Dave won't be taking back orders.  You will just have to wait until they are available and grab one - just like the rest of us.

UPDATE:
Actually, this post of Dave's gives more detail...
@EEVBlog Just receive a "last minute address change" notification from KS. Are the US units about to be shipped?

Yes, we had to lock down the address changes and KS makes us wait 48hours. We actually have like 150 or something last minutes changes!
1000 units will be available end of April (as in available to ship to the various distributors, Welectron for the EU, here for Oz/NZ/others, EUi/KaneTest for the US)
and another 1000 units end of May
(so I guess their production capacity is 1000 units a month)
As before, the remainder of the Great Scott backers will be shipped first. But given that there will be a lot of leftover units from the first 1000 unit batch, many Johnny B. Goode backers will get theirs at the same time.
Title: Re: EEVBlog 121GW Discussion thread
Post by: rpb1 on April 15, 2018, 03:14:17 am
thanks Brumby,

ya i read that post as well... just wasnt sure.

i have no issue with waiting, my Fluke will work fine until then i'm sure !!   
would rather wait for full production anyway when all bugs are vetted.

i'll just wait until it becomes something that can be ordered from the shop.

Title: Re: EEVBlog 121GW Discussion thread
Post by: lacek on April 15, 2018, 08:21:27 pm
is there somewhere a "comparison" of 121GW and say BM869s or other good multimeters say in terms of accuracy? 121GW certainly has lots to otter such as wireless PC connectivity, but this 50mV range seems really cool (though I do not understand what does it mean its only in relative mode).
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on April 15, 2018, 08:45:04 pm
@EEVBlog Just receive a "last minute address change" notification from KS. Are the US units about to be shipped?

Yes, we had to lock down the address changes and KS makes us wait 48hours. We actually have like 150 or something last minutes changes!
1000 units will be available end of April (as in available to ship to the various distributors, Welectron for the EU, here for Oz/NZ/others, EUi/KaneTest for the US)
and another 1000 units end of May
(so I guess their production capacity is 1000 units a month)
As before, the remainder of the Great Scott backers will be shipped first. But given that there will be a lot of leftover units from the first 1000 unit batch, many Johnny B. Goode backers will get theirs at the same time.

A bit confused here - are the US Great Scott units being shipped from the fixed units from before or are they coming from this new batch being shipped at the end of April? Basically just wondering what happened to the original great scott units that made it through customs into the US before they got redirected to KaneTest.

Technically they are the original units.
Title: Re: EEVBlog 121GW Discussion thread
Post by: fanOfeeDIY on April 15, 2018, 11:54:34 pm
Maybe some people laugh :)

I purchased some other 50,000 count handheld DMMs just for the video,
from curiosity of the auto range speed.

I think I need to join the therapy thread. :)

https://youtu.be/3r_a7RUtwpw
Title: Re: EEVBlog 121GW Discussion thread
Post by: glarsson on April 16, 2018, 10:20:41 pm
Is it a fair teat to connect several meters together in ohms mode and drawing conclusions from how they behave? Several meters trying to push sequences of various currents and interpreting the resulting voltage. Chaos. Might work ok with shorted probes, but still...
Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on April 16, 2018, 10:44:31 pm
Is it a fair teat to connect several meters together in ohms mode and drawing conclusions from how they behave? Several meters trying to push sequences of various currents and interpreting the resulting voltage. Chaos. Might work ok with shorted probes, but still...

That was my initial reaction when I first saw that sort of setup - but I think the answer is that it can only work with shorted probes.
Title: Re: EEVBlog 121GW Discussion thread
Post by: bicycleguy on April 17, 2018, 03:18:33 am
...
I think I need to join the therapy thread. :)
..
Yes, you need help :-+
Title: Re: EEVBlog 121GW Discussion thread
Post by: fanOfeeDIY on April 18, 2018, 09:37:11 am
Does your wife know?   :-DD   Looking forward to seeing the high resolution pictures of the two meters.

My wife fount it out..... She saw my video.....

So I told her that you are globally famous which is a good thing :)

Then the reply was silence....

I do not feel I could buy any more multimeter in my life  :'(
Title: Re: EEVBlog 121GW Discussion thread
Post by: fanOfeeDIY on April 18, 2018, 09:48:10 am
Is it a fair teat to connect several meters together in ohms mode and drawing conclusions from how they behave? Several meters trying to push sequences of various currents and interpreting the resulting voltage. Chaos. Might work ok with shorted probes, but still...

That was my initial reaction when I first saw that sort of setup - but I think the answer is that it can only work with shorted probes.

I thought the same.
I am not sure it is in the video, I printed out the spec pages of all multimeters (I had them on right side of the desk) and on manual of DT4282 had the current for every ohm range used, and TY720 had the maximum current could be used for every ohm range. All of the currents were different.

I worried first of damaging the multimeters by current flowing from other multimeters when connecting together.
My brain still only has analog meter age and it might stress the battery inside.
( Then I thought if digital multimeter was so fragile, it would not survive joe's robustness test. :) )
And the shorting the probe all the current from all meters of all ranges could be the same behavior even for the individually shorting the probe.

End up connecting all multmeters together. I am too lazy to make some jig for taking video. :)

Title: Re: EEVBlog 121GW Discussion thread
Post by: Fungus on April 18, 2018, 02:18:21 pm
Then the reply was silence....

:-DD :-DD
There's already a fancy Agilent and another Hioki in the background so I guess he knows what he's doing.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Fungus on April 18, 2018, 03:10:14 pm
Is it a fair teat to connect several meters together in ohms mode and drawing conclusions from how they behave? Several meters trying to push sequences of various currents and interpreting the resulting voltage. Chaos. Might work ok with shorted probes, but still...

That was my initial reaction when I first saw that sort of setup - but I think the answer is that it can only work with shorted probes.

I thought the same.

I worried first of damaging the multimeters by current flowing from other multimeters when connecting together.
My brain still only has analog meter age and it might stress the battery inside.
( Then I thought if digital multimeter was so fragile, it would not survive joe's robustness test. :) )

It wouldn't damage any meter with a proper CAT rating.

OTOH it might skew the test results by giving some meters a head start. eg. Nether the Fluke nor the Hioki are showing "0L" at the start of each test.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Scottjd on April 18, 2018, 03:16:08 pm
Does your wife know?   :-DD   Looking forward to seeing the high resolution pictures of the two meters.

My wife fount it out..... She saw my video.....

So I told her that you are globally famous which is a good thing :)

Then the reply was silence....

I do not feel I could buy any more multimeter in my life  :'(
Ok, so it’s a technicality but this idea might work?
You don’t BUY anymore, just do what some other youtubers do.
Contact bangood and they will send you meters. Then your not buying any of them.
I personally don’t work with bangood so I don’t know how it works. But as long as you disclose it’s from a vendor before the video review or testing I don’t think many people watching care that much these days.
Off the top of my head in the genre of electronic YouTube channels I can think of 3 or 4 that get items all the time from bangood and they still have high subs and views, so it probably doesn’t matter much.
This way you can keep your DMM addiction going without buying another one.  :-+
Title: Re: EEVBlog 121GW Discussion thread
Post by: Fungus on April 18, 2018, 03:22:56 pm
Ok, so it’s a technicality but this idea might work?
You don’t BUY anymore, just do what some other youtubers do.
Contact bangood and they will send you meters. Then your not buying any of them.

There's a place that sends you free multimeters? For free?

Don't let that information reach the therapy thread.  :scared:
Title: Re: EEVBlog 121GW Discussion thread
Post by: Scottjd on April 18, 2018, 03:40:00 pm
Is it a fair teat to connect several meters together in ohms mode and drawing conclusions from how they behave? Several meters trying to push sequences of various currents and interpreting the resulting voltage. Chaos. Might work ok with shorted probes, but still...

That was my initial reaction when I first saw that sort of setup - but I think the answer is that it can only work with shorted probes.

I thought the same.
I am not sure it is in the video, I printed out the spec pages of all multimeters (I had them on right side of the desk) and on manual of DT4282 had the current for every ohm range used, and TY720 had the maximum current could be used for every ohm range. All of the currents were different.

I worried first of damaging the multimeters by current flowing from other multimeters when connecting together.
My brain still only has analog meter age and it might stress the battery inside.
( Then I thought if digital multimeter was so fragile, it would not survive joe's robustness test. :) )
And the shorting the probe all the current from all meters of all ranges could be the same behavior even for the individually shorting the probe.

End up connecting all multmeters together. I am too lazy to make some jig for taking video. :)
My thoughts on the difference in speed for the readings in addition to what others mentioned.
Despite them all being 50k count meters, you will notice they have different levels of resolution for the resistance mode. Not all 50K or even 60K meters offer high resolution in resistance.
So I was wondering if the meters that show a higher resolution could be the reason for a slightly longer time. This gets tricky, because if you manually set the 121GW to display the same resolution as the others it might have an advantage also not having to auto detect the range of the resistance. I guess either way you run it, it still won’t be exactly a far comparison? Then again you could say the 121GW took a little longer because it’s factoring in a higher resolution of resistance to display even in Auto range.
I think even my Fluke 289 60K count meter shows lower resolution then the 121GW does in resistance. 
But it shows the point you were demonstrating, the average speed of the auto range detection.

I would be interesting to see how the 121GW stands against a bench meter that you can set to display the same resolution and still use auto ranging. Maybe something like a much older HP 34401A in two wire mode?
Joe, don’t you own a HP 34401A? I would try this, but I’m missing the 121GW and still waiting.
I know you have a preproduction 121GW, not sure how or if the firmware updates work on your version or if you tried to update it?

Hopefully it comes soon before I move, I figured after the Kickstarter address update request it was going to be just days away before getting a tracking number. It’s getting so close to the dates I’m looking to sell my house I might have to ask for a refund and forgo the idea of reviewing it despite being in the Great Scott group. Even if I get it before I sell my lab might be packed up by then so I wouldn’t be able to do any videos anyway.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Scottjd on April 18, 2018, 03:41:24 pm
Ok, so it’s a technicality but this idea might work?
You don’t BUY anymore, just do what some other youtubers do.
Contact bangood and they will send you meters. Then your not buying any of them.

There's a place that sends you free multimeters? For free?

Don't let that information reach the therapy thread.  :scared:
There’s a therapy thread? Please share, my best friend needs multimeter obsession help.  :-DD
Title: Re: EEVBlog 121GW Discussion thread
Post by: Fungus on April 18, 2018, 04:06:02 pm
There's a place that sends you free multimeters? For free?

Don't let that information reach the therapy thread.  :scared:
There’s a therapy thread? Please share, my best friend needs multimeter obsession help.  :-DD

https://www.eevblog.com/forum/testgear/test-equipment-anonymous-(tea)-group-therapy-thread/ (https://www.eevblog.com/forum/testgear/test-equipment-anonymous-(tea)-group-therapy-thread/)
Title: Re: EEVBlog 121GW Discussion thread
Post by: Scottjd on April 18, 2018, 04:43:54 pm
There's a place that sends you free multimeters? For free?

Don't let that information reach the therapy thread.  :scared:
There’s a therapy thread? Please share, my best friend needs multimeter obsession help.  :-DD

https://www.eevblog.com/forum/testgear/test-equipment-anonymous-(tea)-group-therapy-thread/ (https://www.eevblog.com/forum/testgear/test-equipment-anonymous-(tea)-group-therapy-thread/)

Awesome, thanks. I sent an email to his wife, time to set up an intervention for him. It’s for his own good, he just doesn’t know it yet. Or he’s in denial, maybe he needs to hit bottom first.
Either way, this will plant the seed and it will be up to him.
Thanks for that thread.
Title: Re: EEVBlog 121GW Discussion thread
Post by: VEGETA on April 19, 2018, 03:46:42 pm
How much will it cost when it is ready? how much shipping to Jordan?

I am interested in it since I used to measure low value resistors (0.15) and current flowing through it but my meters weren't optimal for the job. This one should be significantly better overall.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Scottjd on April 19, 2018, 08:03:33 pm
I thought they would have shipped by now. 
According to yesterday’s update I guess the shipping information update request was only for people to receive the PCB and switch fix, not for shipping meters to others. That wasn’t clear, so as it stands not ETA on when the meters will resume shipping. Well this a the official statement “ future shipments which should be commencing again shortly.”
Who knows what shortly is? With this time line I may need to update my address, or maybe not. I guess that depends on what shortly is?
Title: Re: EEVBlog 121GW Discussion thread
Post by: Terry01 on April 19, 2018, 11:53:03 pm
I thought they would have shipped by now. 
According to yesterday’s update I guess the shipping information update request was only for people to receive the PCB and switch fix, not for shipping meters to others. That wasn’t clear, so as it stands not ETA on when the meters will resume shipping. Well this a the official statement “ future shipments which should be commencing again shortly.”
Who knows what shortly is? With this time line I may need to update my address, or maybe not. I guess that depends on what shortly is?
So much for Christmas.  Funny is that you bought it for an early review and even though we are several months into the KS, even if it takes a half year for you to see the meter, you may still be one of the first reviewers.   :-DD


Ha Ha! Hope you get it soon buddy...
Title: Re: EEVBlog 121GW Discussion thread
Post by: Scottjd on April 20, 2018, 05:56:09 pm
I thought they would have shipped by now. 
According to yesterday’s update I guess the shipping information address update request was mostly for people receiving  the PCB and switch fix, not for shipping meters to those still waiting. That wasn’t clear on the address update request, so as it stands no ETA on when the meters will resume shipping. Well the official statement is  “future shipments which should be commencing again shortly.”
Who know what shortly is? With this time line I may need to update my address before shorty happens? I guess that depends on what shortly is defined as?
So much for Christmas.  Funny is that you bought it for an early review and even though we are several months into the KS, even if it takes a half year for you to see the meter, you may still be one of the first reviewers.   :-DD

LOL, some day, maybe someday? I know Vegeta just asked about it based on the resolution it displays for reading resistors. I thought to myself that is what I was planning for my review was accuracy of the meter at a decent price for the resolution.
I did invest a chunk of money for new precision resistors to go with the ones I already owned used in the BM235 review, and used to benchmark the HP 34401A when I received it 2 years ago. I still have the same voltage standard I built and it’s still accurate as the day I tuned it after it warms up. I hope to show that the HP bench meter hasn’t drifted in two years and it’s  still as accurate from when I did the BM235 review. Even bought a new low value capacitor standard to show higher resolution readings in these mode. Even my Fluke 289 has a hard time displaying this capacitor standard correctly unless I manually range it. I couldn’t find all the resistors ranges I wanted in a milspec 0.025% accuracy with low temperature coefficiency like the ones I already own, so some of the higher values I bought are 0.1% to 1% tolerances like the 10M ohm, 1G ohm values. I need to build a little box like yours, I bought a box for this, just never had the time to move all the resistors into the box yet.
The plan was to show the features, accuracy and precision of the 121GW compared to some bench meters and see ifs it can be a good mobile alternative,  or smaller option to save on bench space for the hobbiest. I have one 5 digit meter that is NIST certified that partially validates my 6.5 digit 34401A so I know it’s still reading accurate, and other logging meters  Fluke 289 I planed to compare with on long 24/48 hours logging sessions.   Now that I’m thinking of this again the NIST certification may be expired on the 5 digit meter now, or might be expired by the time I get the 121GW meter. But it was still valid in December and January.

Was looking forward to possible third party firmware for future features like power factor calculation readings with AC LED lights, but with the VA now limited to the 50V range I don’t think this would be possible anymore like on the mooshie meter.  I might end up buying another mooshie before I get the 121GW since technically it’s a Bluetooth logging meter for comparison if they have fixed the app issues. I did test it shortly after iOS 11, so this could have been a lot of the app and Bluetooth disconnect issues I was seeing? Or keep using a $29 kilowatt meter for power factor readings, but I was looking for the all in one meter.

Open source firmware was a selling point. Although not all open source t I think it’s been reversed engineered enough to make changes. I believe these talented coders are waiting for a near final firmware before making any bug changes. Maybe these same people that can code might make a better iOS Apple app also since to my knowledge the official EEVBlog iOS app still isn’t done.  Just a generic app from the manufacturer is available. I thought with the extra time on delays and shipping the EEVBlog iOS official app might have been completed by now? Heck, a one time bottom banner ad at the app launch during BT pairing could produce a residual income to pay for any yearly app fee, and if the meter takes off it might even turn a profit for future development and all improvements.

Since I invested money to do a good/bad review I’m trying to hang in with this. Ok,  I don’t really do “bad reviews” or thumbs down fail reviews, I try to do honest reviews for people to decide if the product is the best for the users needs. Sometimes you need more then one tool for the job, but it’s always nice if you can find one tool that does everything you need for your job. If I didn’t buy theses new resistors and capacitor standards I probably would have asked for a refund months ago.

Ideas, plans, life decisions, I seem to be waiting on other factors I don’t have any control over.  Once winter ends I can start to pack the house to sell. It was snowing again today and I have a birds that nested over my outside solar light and it’s snowing,  probably hope the LED lights will keep them warm. Since winter “supposedly” ended we have had a few nice mid 70’s days, but also a tornado that touch down, a few thunderstorms, then back to freezing and snow three more times. What weird weather this year. So I can’t sell stuff in my house to move until the weather gets nicer. So I guess the sale of the house is waiting on this, I don’t want to move everything.  Hopefully I’ll get the 121GW before the house sells, if not another address change? I would also need to set up the lab again after the move that will just delay the review and take more time. But maybe that works better since I prefer to test things for 2 to 4 weeks before doing any review. I’ve waited this long, and so have others so what’s another few weeks?
Title: Re: EEVBlog 121GW Discussion thread
Post by: maukka on April 21, 2018, 10:13:16 pm
FWIW here's one 121GW against Ian Johnston's PDVS2 10V reference (http://www.ianjohnston.com/index.php/onlineshop/handheld-precision-digital-voltage-source-v2-detail).

PDVS2   121GW
0.5000 V   0.5000 V
1.0000 V   1.0000 V
1.5000 V   1.5000 V
2.0000 V   2.0000 V
2.5000 V   2.4999 V
3.0000 V   2.9999 V
3.5000 V   3.4999 V
4.0000 V   3.9999 V
4.5000 V   4.4999 V
5.0000 V   5.0000 V
5.5000 V   5.499 V
6.0000 V   5.999 V
6.5000 V   6.499 V
7.0000 V   6.999 V
7.5000 V   7.499 V
8.0000 V   7.999 V
8.5000 V   8.499 V
9.0000 V   8.999 V
9.5000 V   9.499 V
10.0000 V   9.999 V
Title: Re: EEVBlog 121GW Discussion thread
Post by: maukka on April 22, 2018, 01:22:50 am
Don't have the meter anymore.
Title: Re: EEVBlog 121GW Discussion thread
Post by: VEGETA on April 22, 2018, 09:13:27 am
What about its capabilities in measuring small resistances like 0.1R or so?
Title: Re: EEVBlog 121GW Discussion thread
Post by: Scottjd on April 23, 2018, 04:36:58 pm
Did you have your standards calibrated so we have some known reference? 

One of the videos I had pulled was comparing the pre-production meter with the 34401 and my BK LCR meter.   Dave had said early on that the meter may not have been in cal but I seem to recall it being pretty decent.   

OK, watching it now... Wow was it painful to watch it read a 150pf capacitor.  I wonder if the new firmware and final hardware is still this slow.   Accuracy wise, looks fairly impressive considering this was after I had damaged the meter twice and had modified it.   Looking forward to seeing the final version ran.
I have capacitor standards, as for the resistors they are just expensive Vishay mill spec low ppm high efficiency new resistors. Even if my lab temperature drifts 3 Celsius they will read the same, but my lab doesn’t drift that much. I already logged the lab temp for 48 hours and it was almost 1 degree Celsius max drift in temperature.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Scottjd on April 23, 2018, 04:39:36 pm
What about its capabilities in measuring small resistances like 0.1R or so?
I have a precision current shunt resistor for ghaynvalie, I think I own two. And I own two 4 wire kelvin miliohm meter to confirm then accuracy. So I plan to see if it can measure that low, and lower with fuses and 100mm strips of nickel since I can easily calculate the knows resistance of nickel from my battery spot welding rig. So I’ll let you know once I get mine.

But despite the resolution with it being only a 2 wire measument, I don’t expect lower reading from a handheld meter to be that accurate. It does show a higher resolution then any of the other meters I own for resistance, so it may surprise me. I’ll have to keep waiting to find out.
Title: Re: EEVBlog 121GW Discussion thread
Post by: VEGETA on April 23, 2018, 06:12:35 pm
So for example is the Chinese LCR meter (30$) on Banggood or Aliexpress a better choice for the job than this expensive DMM?
Title: Re: EEVBlog 121GW Discussion thread
Post by: BravoV on April 23, 2018, 07:06:11 pm
So for example is the Chinese LCR meter (30$) on Banggood or Aliexpress a better choice for the job than this expensive DMM?

Even better, a $5 cheap DMM + a cheap DIY constant current power supply, will make you able to measure sub 1 Ohm quite accurate, as long you understand the principal of 4 wires measurement.

2 wires probe DMM even the expensive one, can NOT measure sub 1 Ohm reliably.
Title: Re: EEVBlog 121GW Discussion thread
Post by: VEGETA on April 23, 2018, 07:09:28 pm
So for example is the Chinese LCR meter (30$) on Banggood or Aliexpress a better choice for the job than this expensive DMM?

Even better, a $5 cheap DMM + a cheap DIY constant current power supply, will make you able to measure sub 1 Ohm quite accurate, as long you understand the principal of 4 wires measurement.

2 wires probe DMM even the expensive one, can NOT measure sub 1 Ohm reliably.

I came to realize that by practice after making 0.15R resistor out of 15 1.5R ones to act as a power resistor. It gets even worse when I connected my multimeter to measure current passing through it, then multimeter internal resistance was added to make the whole measurement unreliable.

Title: Re: EEVBlog 121GW Discussion thread
Post by: HKJ on April 23, 2018, 07:13:38 pm
I came to realize that by practice after making 0.15R resistor out of 15 1.5R ones to act as a power resistor. It gets even worse when I connected my multimeter to measure current passing through it, then multimeter internal resistance was added to make the whole measurement unreliable.

If you want about basic current measurement, maybe my article can help: https://lygte-info.dk/info/DMMCurrent%20UK.html
Title: Re: EEVBlog 121GW Discussion thread
Post by: BravoV on April 23, 2018, 07:14:04 pm
I came to realize that by practice after making 0.15R resistor out of 15 1.5R ones to act as a power resistor. It gets even worse when I connected my multimeter to measure current passing through it, then multimeter internal resistance was added to make the whole measurement unreliable.

Either you've made a mistake, or you have a really crappy DMM that has internal resistance is so low in voltage mode that affect that kind of reading.
Title: Re: EEVBlog 121GW Discussion thread
Post by: coromonadalix on April 23, 2018, 07:49:33 pm
if youre able to zero out the leads impedance with the meter, it may do some 0.x ohms resistors, but an dmm is not an milliohms tester with or without 4 wire modes, it has is limits too, unless specefically built for that ...

the video give an good example of low impedance measurements

@vegeta
I think youve made an error to put the meter in parallel with your 0.15 ohm resistor, you measure current in serie
 
To minimize the chance of blowing fuses or overheating the meter, i use a precision 0.1 ohms 20watt,  put the load in serie with ac or dc current,  with the formula    V = R x I

I read in millivolts the voltage across the load and do the maths,  it save tons of expensives fuses if it goes wrong.   0.1 ohm is 1/10th of the current value passing thru and read in an dmm, 

For more precise current measurements, you have clamp meters, or clamp meter attachements for dmm's, they can be very precise and go very low in current in some models, you can zero the inputs too...
Title: Re: EEVBlog 121GW Discussion thread
Post by: Scottjd on April 23, 2018, 08:23:33 pm
So I’ve been testing this meter, I bought two of them. One from Ebay and one from Amazon. The Amazon came with the Kevin clips also that are useful.
I usually test thing thoroughly before I recommend them, and this meter is not advertised as a miliohm meter. It’s desinged and sold as a battery internal resistance tester. I’ve compared this to three others for batteries and this is the only one that meets the standard these days that battery manufactures are using to measuring the IR of high current discharge battery cells. All my knows cells from data sheets match near perfect when I use this meter. The battery IR standard is using a 1Khz AC signal with a known current. Both are almost exactly 1Khz compared to others that allowed a 10% variance and gave bad results.

Then I realized this could probably also do miliohm measuments since the signal and current are so stable and accurate. So far they have worked great. I’ve measured accurately down to 6.9 miliohms from a known part and lower but not confirmed if the lower readings were accurate. For example and pure nickel strip best for carrying currents between battery lithium cells from 10 to 15 amps that is 0.15mm thick, by 8mm wide and 100mm long should measure at 6.9 miliohms. Unfortunately a lot of sellers on eBay sell “pure nickel”, but it’s realy nickel plated steel/iron. Nickel plated with the same size will only carry 2 to 7 amps. The variance realy depends on the quality of your spot weld, but either ways that’s a big difference. Nicrome wire is another know easy to measure material by gauge and length, so then I realized I can confirm fake counterfeit fuses from real fuses with this meter also, and it worked great.

So if you want a cheap and accurate way to measure miliohms that you can also use to measure internal resistance of batteries with I recommend you try this meter. It’s a little more on the affordable side compared to other meters with the same accuracy and performance. The one downfall is because it’s not officially a meter like a DMM it’s not fused and has no protection like PTC to clamps down. This shouldn’t be used to try and measure any current accross something except for on batteries as it’s designed. It works on lithium, LiFe, alkaline and every type of cell I’ve tested so far.
https://www.amazon.com/gp/product/B0768WQJQC/ref=oh_aui_search_detailpage?ie=UTF8&psc=1 (https://www.amazon.com/gp/product/B0768WQJQC/ref=oh_aui_search_detailpage?ie=UTF8&psc=1)

I usually don’t talk about my reviews and upcoming videos I’m working on, but since this seems to be a hot topic lately and some ones asked me if I have and English version of the manual I figured I would add this. So I’ve also attached the draft translation of the manual, this is not completed yet, it’s about 85% done being translated and compared to the features of the meters I’m testing. If someone else owns this meters d would like to help translate and formate parts I haven’t finished near the end to a sensible translation (not translations from google or bing that have sentences that are lost in translation and don’t make sense) then let me know. I have the soft version and the draft in a word doc for easy editing.
I hope to have the review video completed soon on this meter.

I hope this helps, now we can return to the regularly scheduled topic of this thread.  :-DD
Scott

Ok, now I’m going back to sleep. Have fun.
Edit, fixed half a sleep spelling errors.  |O
Title: Re: EEVBlog 121GW Discussion thread
Post by: HKJ on April 23, 2018, 08:48:21 pm
So if you want a cheap and accurate way to measure miliohms that you can also use to measure internal resistance of batteries with I recommend you try this meter.

"This little meter" is easy to get from China in two different versions, I have done review of both:

YR1030: https://lygte-info.dk/review/InternalResistanceMeterYR1030%20UK.html
YR1035: https://lygte-info.dk/review/InternalResistanceMeterYR1035%20UK.html

But if you buy from China you risk getting a model with only Chinese text (It is not that big of a problem).
Title: Re: EEVBlog 121GW Discussion thread
Post by: Scottjd on April 23, 2018, 09:27:32 pm
This is the word doc I anyone else want to make corrections to the manual.
Title: Re: EEVBlog 121GW Discussion thread
Post by: HKJ on April 23, 2018, 09:47:26 pm
battery company that went out of buisness.

No company went out of business. There website is here: http://www.vapcelltech.com/ (http://www.vapcelltech.com/)  with recent updates.

maybe to see if you had a user manual.

I do have a English user manual (photos) for the old version, but the new version has a few changes.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Scottjd on April 23, 2018, 10:16:51 pm
battery company that went out of buisness.

No company went out of business.

maybe to see if you had a user manual.

I was told by several that VapeCell went out of buisness. They only relabeled the meter, I wasn’t saying the one who makes it went out of buisness. But at the time when I researched it the valecell domain was sold off, the Skype account was closed, the email was rejected by the server for unknown recipient. So I confirmed it with some other contacts.  Or did they start back up again? This was in November or December I think.
Title: Re: EEVBlog 121GW Discussion thread
Post by: maukka on April 23, 2018, 10:23:30 pm
For example and pure nickel strip best for carrying currents between battery lithium cells from 10 to 15 amps that is 0.15mm thick, by 8mm wide and 100mm long should measure at 6.9 miliohms.

Sorry about the offtopic.

That's a nice tip, but are you sure it's true? I don't have a big enough stock to test and verify, but to determine if my Chinese strips are pure or just plated I have tried to dremel them and see if sparks fly or scratch them and put into salt water for a couple of days to see if they rust.

https://www.youtube.com/watch?v=Xr4gqUDWxgg (https://www.youtube.com/watch?v=Xr4gqUDWxgg)
https://www.youtube.com/watch?v=w40t0RxQd3Q (https://www.youtube.com/watch?v=w40t0RxQd3Q)

I just measured a couple nickel strips one of which I suspected to be nickel plated steel judging by the mentioned tests (it sparked when ground and rusted faster although took several days), but the resistance isn't that far off taking into account the thickness.

Strip 1: 8 x 0.27 mm:   5.70 mOhm (/10 cm) (suspected real deal)
Strip 2: 10 x 0.20 mm: 6.87 mOhm (/10 cm) (suspected nickel plated steel)

(https://i.imgur.com/PUgh4rR.jpg)
Title: Re: EEVBlog 121GW Discussion thread
Post by: Scottjd on April 23, 2018, 11:20:05 pm
Valid question, truth be told their is not much of a difference between them as you will see in the picture. But it was enough to confirm the roll I bought was real. And you rod need both pieces to be exactly the same strips in length width and thickness for a fair comparison for any of these tests to be valid.
You will also see an obvious difference in the plating texture in the pictures.
I’ve had some other thoughts also, but haven’t tried them yet. I’m not patient for some things and want the easy test now answer.
One of my other thoughts was the putting 10 amps through both and messing with the FLIR.  Ignore the temperature reading due to the in the metal reflective emissivity, but you should still see the colors indicate what one gets hotter over a minute.

I really notice the difference when welding, the nickel will burn through easier if the current is up to high. Or the steel plated will need you to turn up the machine to get a good weld.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Scottjd on April 23, 2018, 11:21:20 pm
Ifyou look at the pictures the steel plated one at about a 50mm length can support a 100g weight. The pure nickel bent and fell through the vise so I pulled the weight off and just set it aside.
It’s been a while since I was so active in a thread. Well it’s been fun, but I’m having issues typing now with my finger cramping up so I’m going offline.
Title: Re: EEVBlog 121GW Discussion thread
Post by: fanOfeeDIY on April 23, 2018, 11:33:19 pm

It wouldn't damage any meter with a proper CAT rating.

OTOH it might skew the test results by giving some meters a head start. eg. Nether the Fluke nor the Hioki are showing "0L" at the start of each test.

Thanks, Fluke 87V and Hioki DT4282 are not showing OL.
The fluke and hioki are the ones have lower current on measuring ohm and it might related to it.

Also, it might be behaving differently when scanning between the ranges to find the right range.

Well, I am a lazy person. :)
Title: Re: EEVBlog 121GW Discussion thread
Post by: fanOfeeDIY on April 23, 2018, 11:39:12 pm
Ok, so it’s a technicality but this idea might work?
You don’t BUY anymore, just do what some other youtubers do.
Contact bangood and they will send you meters. Then your not buying any of them.
I personally don’t work with bangood so I don’t know how it works. But as long as you disclose it’s from a vendor before the video review or testing I don’t think many people watching care that much these days.
Off the top of my head in the genre of electronic YouTube channels I can think of 3 or 4 that get items all the time from bangood and they still have high subs and views, so it probably doesn’t matter much.
This way you can keep your DMM addiction going without buying another one.  :-+
[/quote]

I started to take videos just for my fun in my time, one was to keep my English.

If I become more serous of taking the video in the future, then I might need to think the content of the video with more meters.

The main concern is taking spaces in the room at the moment. (I think) :)
Title: Re: EEVBlog 121GW Discussion thread
Post by: fanOfeeDIY on April 23, 2018, 11:40:14 pm
There's a place that sends you free multimeters? For free?

Don't let that information reach the therapy thread.  :scared:
There’s a therapy thread? Please share, my best friend needs multimeter obsession help.  :-DD

https://www.eevblog.com/forum/testgear/test-equipment-anonymous-(tea)-group-therapy-thread/ (https://www.eevblog.com/forum/testgear/test-equipment-anonymous-(tea)-group-therapy-thread/)

 :-DD :-DD
Title: Re: EEVBlog 121GW Discussion thread
Post by: fanOfeeDIY on April 23, 2018, 11:45:09 pm

I found this video where he pulls apart the Yokogawa.  Looks like they have some sort of gas tubes.   The Gossen used GDT's and held up very well in the transient tests.  The Keysight meter I looked at also used GDTs and was damaged early on in the testing.   

Does your meter look the same inside as this one?


Sorry for scaring people that I am not uploading images on the forum.
(I am not killed yet for having too much meters) :)

I just finished taking high resolution images.
I found some of the images which I took after the last video were not showing good for uploading to eebvlog.
I was considering to take the some images again, then I became busy.

I will upload them soon.
Title: Re: EEVBlog 121GW Discussion thread
Post by: nidlaX on April 24, 2018, 01:29:11 pm
Is there a more concrete timeline available for the shipping of the US meters? I may need to change my address again if the meters don't ship within a few weeks.
Title: Re: EEVBlog 121GW Discussion thread
Post by: fanOfeeDIY on April 24, 2018, 04:52:14 pm

Thanks for taking the pictures.   Looking forward to seeing them.


I finally uploaded them here.
https://www.eevblog.com/forum/testgear/ty720-kew-1062-handheld-multimeter-inside-high-resolution-images/ (https://www.eevblog.com/forum/testgear/ty720-kew-1062-handheld-multimeter-inside-high-resolution-images/)
Title: Re: EEVBlog 121GW Discussion thread
Post by: knapik on April 24, 2018, 08:20:34 pm
I got the switch shim fix and new knob and installed it today. The knob itself is much tighter now, and it seems to have helped the turning off issue I was constantly having near the Ohms and power selection. For a little bit, I was still having the same issue where the multimeter was turning off, but after a little bit of time, it seems to have settled in, and I can't replicate it even with some spirited jiggling.
Title: Re: EEVBlog 121GW Discussion thread
Post by: VK5RC on April 24, 2018, 08:28:41 pm
Thanks, I also got the shim and new knob, went in well, definitely a bit firmer now - but I didn't have any problems before! :-+
Title: Re: EEVBlog 121GW Discussion thread
Post by: ANTALIFE on April 24, 2018, 10:43:05 pm
Looks like I am one of the unlucky ones that only got shipped a replacement knob but no shim ; - ;
Have contacted Dave to try and get the shim re-shipped
Title: Re: EEVBlog 121GW Discussion thread
Post by: 1anX on April 26, 2018, 08:41:42 am
Looks like I am one of the unlucky ones that only got shipped a replacement knob but no shim ; - ;
Have contacted Dave to try and get the shim re-shipped

 :palm: :palm: :palm: :palm: :palm:
Title: Re: EEVBlog 121GW Discussion thread
Post by: morrone on April 26, 2018, 01:22:29 pm
I had a fairly long logging session recently that logged DC V while charging a 12V battery.  I left it on the default logging rate, thinking that was once per second, but it turns out that my meter defaulted to "0", so according to the manual was actually logging at the fastest rate of around 200ms.

Around 25-26 hours later I went to the meter and saw a voltage of around 13.67V.  My victron BMV-712 told me that current down to nothing, so that was as far as the charger was going to take it.  I stopped the logging, and the beginnings and end of the log file look like:

START,2018/04/24,16:45:07,
ID,170800000,
INTERVAL,000,sec,
,MAIN,,,SUB-1,,,SUB-2,,,Remark,
No. ,Func. ,Value,Unit,Func. ,Value,Unit,Func. ,Value,Unit,
1,DCV,013.182,V,,,,,,,,
2,DCV,013.188,V,,,,,,,,
3,DCV,013.187,V,,,,,,,,
4,DCV,013.187,V,,,,,,,,
5,DCV,013.187,V,,,,,,,,
6,DCV,013.187,V,,,,,,,,
[cut]
364219,DCV,013.529,V,,,,,,,,
364220,DCV,013.530,V,,,,,,,,
364221,DCV,013.529,V,,,,,,,,
364222,DCV,013.530,V,,,,,,,,
364223,DCV,013.529,V,,,,,,,,
364224,DCV,013.529,V,,,,,,,,
364225,DCV,013.530,V,,,,,,,,
364226,DCV,013.529,V,,,,,,,,
MAX,67374,DCV,013.531,V,
MIN,1,DCV,013.182,V,

Something is very odd here.  The last sample was 13.529V, and the max was recorded as 13.531.

I am not sure what happened here.  It doesn't help that the meter only logs sample count, and not time.  If I really assume that it took a sample every 200ms, then the meter only logged for a little over 20 hours.  But I know that I stopped it a minimum of 25 hours later.  So, OK, 200ms is approximate.  So maybe its is more like every 250ms on average...that would work out to a little over 25 hours (after 364226 samples).

But if it really was logging up until the point that I stopped it, then why were there no records of the 13.67V readings that I saw on the display (and was also reported by the Victron BMV-712)?
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on April 26, 2018, 02:37:54 pm
I got the switch shim fix and new knob and installed it today. The knob itself is much tighter now, and it seems to have helped the turning off issue I was constantly having near the Ohms and power selection. For a little bit, I was still having the same issue where the multimeter was turning off, but after a little bit of time, it seems to have settled in, and I can't replicate it even with some spirited jiggling.

Maybe there was some form of contaminant on the pads or contacts that eventually wiped away?
Title: Re: EEVBlog 121GW Discussion thread
Post by: Seppy on April 26, 2018, 02:53:15 pm
Looks like I am one of the unlucky ones that only got shipped a replacement knob but no shim ; - ;
Have contacted Dave to try and get the shim re-shipped

I have now shipped the part.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Seppy on April 26, 2018, 04:34:38 pm
I had a fairly long logging session recently that logged DC V while charging a 12V battery.  I left it on the default logging rate, thinking that was once per second, but it turns out that my meter defaulted to "0", so according to the manual was actually logging at the fastest rate of around 200ms.

Around 25-26 hours later I went to the meter and saw a voltage of around 13.67V.  My victron BMV-712 told me that current down to nothing, so that was as far as the charger was going to take it.  I stopped the logging, and the beginnings and end of the log file look like:

START,2018/04/24,16:45:07,
ID,170800000,
INTERVAL,000,sec,
,MAIN,,,SUB-1,,,SUB-2,,,Remark,
No. ,Func. ,Value,Unit,Func. ,Value,Unit,Func. ,Value,Unit,
1,DCV,013.182,V,,,,,,,,
2,DCV,013.188,V,,,,,,,,
3,DCV,013.187,V,,,,,,,,
4,DCV,013.187,V,,,,,,,,
5,DCV,013.187,V,,,,,,,,
6,DCV,013.187,V,,,,,,,,
[cut]
364219,DCV,013.529,V,,,,,,,,
364220,DCV,013.530,V,,,,,,,,
364221,DCV,013.529,V,,,,,,,,
364222,DCV,013.530,V,,,,,,,,
364223,DCV,013.529,V,,,,,,,,
364224,DCV,013.529,V,,,,,,,,
364225,DCV,013.530,V,,,,,,,,
364226,DCV,013.529,V,,,,,,,,
MAX,67374,DCV,013.531,V,
MIN,1,DCV,013.182,V,

Something is very odd here.  The last sample was 13.529V, and the max was recorded as 13.531.

I am not sure what happened here.  It doesn't help that the meter only logs sample count, and not time.  If I really assume that it took a sample every 200ms, then the meter only logged for a little over 20 hours.  But I know that I stopped it a minimum of 25 hours later.  So, OK, 200ms is approximate.  So maybe its is more like every 250ms on average...that would work out to a little over 25 hours (after 364226 samples).

But if it really was logging up until the point that I stopped it, then why were there no records of the 13.67V readings that I saw on the display (and was also reported by the Victron BMV-712)?

Just a few questions:
- Did you read the 13.67V on the 121GW or another device (Error potentially in reference)
- Does your 121GW measure 13.5V correctly if simply given DC (Error potentially in calibration)
- What version of firmware do you currently have (So I can test against that version)
- Did sample 67374 correlate to the 13.531 V MAX value?
- What was your charging setup?
Title: Re: EEVBlog 121GW Discussion thread
Post by: knapik on April 26, 2018, 09:32:30 pm
I got the switch shim fix and new knob and installed it today. The knob itself is much tighter now, and it seems to have helped the turning off issue I was constantly having near the Ohms and power selection. For a little bit, I was still having the same issue where the multimeter was turning off, but after a little bit of time, it seems to have settled in, and I can't replicate it even with some spirited jiggling.

Maybe there was some form of contaminant on the pads or contacts that eventually wiped away?

I'm not too sure actually. I accidentally had the contacts in the wrong position for the first time I put the meter together resulting in all the positions being shifted, so when I took it apart again I rotated the contacts themselves to the off position before putting the dail back in. It did happen once again after I wrote my previous post, but its not something I can replicate consistently. It could be something like a bit of contamination, or the contacts being picky with the initial position. I'll mention it if I'm having any further issues with the multimeter resetting.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Insatman on April 27, 2018, 11:05:05 am

I am not sure what happened here.  It doesn't help that the meter only logs sample count, and not time.  If I really assume that it took a sample every 200ms, then the meter only logged for a little over 20 hours.  But I know that I stopped it a minimum of 25 hours later.  So, OK, 200ms is approximate.  So maybe its is more like every 250ms on average...that would work out to a little over 25 hours (after 364226 samples).


Question...Does the 121GW log counts not time because it lacks a real-time clock?   Could some sort of time-stamp be implemented in the log data in future based on the calculated time from sampling frequency?   This would really be helpful.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Cliff Matthews on April 27, 2018, 12:29:12 pm
Question...Does the 121GW log counts not time because it lacks a real-time clock?   Could some sort of time-stamp be implemented in the log data in future based on the calculated time from sampling frequency?   This would really be helpful.
RTC is U7. Here's the data sheet.
Title: Re: EEVBlog 121GW Discussion thread
Post by: morrone on April 27, 2018, 12:34:11 pm

Just a few questions:
- Did you read the 13.67V on the 121GW or another device (Error potentially in reference)
Yes, I saw 13.67V on the LCD display of the 121GW, and confirmed the value with another device before I ended logging by holding down the MEM button.  Both devices agreed fairly closely.  In hind sight, I probably should have made note of what the sample counter was doing on the LCD before ending logging.
Quote
- Does your 121GW measure 13.5V correctly if simply given DC (Error potentially in calibration)
I don't have any reason to believe that particular value is wrong.  The calibration reasonably matched a couple of my other meters last time I checked.  I'm running a log of a discharge cycle at the moment, but I will double check the calibration after that.  UPDATE: Yes, it matches two other meters quite closely measuring 13.5V.
Quote
- What version of firmware do you currently have (So I can test against that version)
1.10
Quote
- Did sample 67374 correlate to the 13.531 V MAX value?
Yes, sample 67374 was the first instance of 13.531V in the file.
Quote
- What was your charging setup?
This is in a travel trailer.  A WFCO WF-8735 is charging a Greenlife GL100 LiFePo battery (with built-in BMS to tolerate being used as a lead acid battery drop in replacement, even if it isn't ideal).  At the start of the log the WF-8735 is in constant current mode and was delivering just under 36A according to the victron battery monitor (the WF-8735 is rated for 35A, so that is fairly reasonable).  The leads of the 121GW are clipped directly to terminals on the battery posts.

The voltage in the logs gradually rises from 013.182V at the start to 13.531V at sample 67374.  After that the voltage hovers around 13.527V to 13.531V for the rest of the log.  I'm willing to share the log, but it is 11MB in size.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Insatman on April 27, 2018, 06:35:35 pm
Question...Does the 121GW log counts not time because it lacks a real-time clock?   Could some sort of time-stamp be implemented in the log data in future based on the calculated time from sampling frequency?   This would really be helpful.
RTC is U7. Here's the data sheet.

So...if it has an RTC...why not log timestamps?   Why make the user guess or try and figure it out...makes no sense.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Iagash on April 27, 2018, 08:40:10 pm
Update has been released to the app stores, likely hasn't updated on both yet but these issues should all be resolved now, we also have a new firmware version which will be resolving one of the other issues (when the voltage in VA mode is above 32767 approximately, this firmware update hasn't been released, this issue was a packet issue not a app issue so for those values you'll need to wait for the next firmware update).

Ok, with the new firmware 1.15 the wrong values in VA mode seem to be fixed. I still get checksum error on around 2% of the packets and the update rate seems to be reduced to about 2 packets per second.

Would you please push your app changes to the gitlab repo as I suspect the RangeLookup table in Packet121GW.cs has changed. I'd like to add your changes to my script.

Thanks!
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on April 27, 2018, 10:00:24 pm
v1.15 has been released, it's on the website for download. There are various small fixes.
Please everyone use that latest version when reporting issues, we want everyone on the same page.

Update on the shipping:
50 units coming to me on May 5th (the original lost 50), 1000 more units available from May 19th, and another 1000 units ASAP after that.
Kickstarter update will come tomorrow when I get back from holidays.
Title: Re: EEVBlog 121GW Discussion thread
Post by: VK5RC on April 28, 2018, 07:34:12 pm
Sorry for being a bit slow but where is the current version ie which website?
Thanks
Title: Re: EEVBlog 121GW Discussion thread
Post by: djadeski on April 28, 2018, 07:40:26 pm
You can find the files here: https://www.eevblog.com/product/121gw/ (https://www.eevblog.com/product/121gw/)

-dave
Title: Re: EEVBlog 121GW Discussion thread
Post by: kalross on April 29, 2018, 03:42:39 pm
Did any European early birds get the shim sent to them yet?  My meter dial has started to play up and I haven't received the shim.

Title: Re: EEVBlog 121GW Discussion thread
Post by: Vespian on April 29, 2018, 03:45:10 pm
With the added shipping delays for the US meters, I am going to need to change my shipping address. I was one of the Great Scott! backers.
Title: Re: EEVBlog 121GW Discussion thread
Post by: peteb2 on April 29, 2018, 05:37:27 pm
Just read Dave's latest update news of what's happening (sent as an email to Backers).

I just have gotta say from the point of view of someone who has backed a few Crowd Funded Projects now (where all of them delivered on time complete with their included Goal Additions)... this one has come unstuck a wee bit and i think it's simply because of it's own massive demand and therefore success.

With Dave having worked closely on the 121GW DMM's design and effectively endorsing it, it's a wonder it didn't blow out to 100s of 1000s of the things if not more being backed in the campaign.

I was so slow to get myself organized to do my backing in that i ended up in the Johnny Be Good group. I'd finally like to say i wouldn't want to be in Dave's role with a lot of folks who by now are sort of starting to wonder what's really happening but that i know the unit will eventually be a handy addition to my bench and that it's not the end all to wait as long as it needs for the thing to arrive....  ;)

Title: Re: EEVBlog 121GW Discussion thread
Post by: Candid on April 29, 2018, 07:38:38 pm
Did any European early birds get the shim sent to them yet?  My meter dial has started to play up and I haven't received the shim.
I am still waiting for delivery. I recognize the shim problem since about 2 weeks now.

If you are one of the early birds you should have the same version as me. Can you please check something for me?

When I shorten the voltage input to com and set the 121GW to voltage AC 5V range I get a value of about 0,4999V displayed. When I open the short it is nearly the same (a little more maybe 0,5001V). In all other voltage AC or DC ranges I get 0,0xxxV when the input is shortened.

I tried to calibrate zero offset but this did not help. The last firmware (v1.15) did not too.
Title: Re: EEVBlog 121GW Discussion thread
Post by: fanOfeeDIY on April 29, 2018, 08:02:19 pm
Did any European early birds get the shim sent to them yet?  My meter dial has started to play up and I haven't received the shim.
I am still waiting for delivery. I recognize the shim problem since about 2 weeks now.
 calibrate zero offset but this did not help. The last firmware (v1.15) did not too.

I am in Japan and I received the email that the shim set being sent on last Thursday and it has not been delivered to my home yet.

It could be simply it having delay at the custom. Normally it arrives in about five week days from Australia to Japan.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Scottjd on April 29, 2018, 09:54:41 pm
Dave,
I honestly don’t know if I will need to change my address or not based on the update email, obviously EUI should start shipping the next 1050 units. So if I understand this correctly the first 50 goes to Australia, then the next 1000 remaining EUi sends out goes to different fulfillment shippers based on the addresses in the remaining “great Scott” option? Since the “Great Scott” was only 450 I’m to assuming this supply will cover the remaining “Great Scott” supports on May 19th?

Now the question becomes if I change my address on Kickstarter how fast does this data get to EUI or the shipper like Kane for US customers and refreshed, and then passed onto Kane for the US shipper? Can we get a hard cutoff date to when the last date will be to change the address in Kickstarter?
I can’t give or know a hard date on when my address will change, if your have ever sold a house before then you know things can change at the last minute that will also change the date of the sale.

I don’t know about other country local posts but the US post office will not forward packages. The original shipping method was to be done with DHL as original mentioned in the “Great Scott” package I selected on Kickstarter. But it seems DHL isn’t handling any of these shipments now and was originally changed in the beginning also, that’s my assumption from the beginning logistics that seemed to be changed and was part of the original hold up at US customs.

I think a little more details will help me and others in my situation figure out what steps we might need to make next. For example, I have a UPS, USPS, and FedEx account. If I at least know what shipping carrier Kane will be using and the package is tracking then I may have different options to ensure I get the package without involving the Kickstarter address change.

If Kane is using USPS then my address forwarding will just screw this up. This means I need to do the Kickstarter address update and why the hard date would be useful and hope this change of address gets from Kickstarter, to Dave, then to Kane in time before it ships.

If I know Kane is using UPS for shipping then I don’t have to worry about my USPS post office forwarding and the meter package being returned, or worse case the new owner of my house keeping it. For this reason I hope these are being shipped insured?
I can work with my UPS account once I have a tracking number and request it be delivered to my new address or I can set up a UPS/or FedEx P.O Box. I would have done this already, but we never had a sure date in when shipping would continue and I couldn’t afford paying on a P.O. box since December just for this meter.

I can’t change Kickstarter to a confirmed new address since I have to sell the house first before buying a new one. And I was hoping to take a holiday that I haven’t had in 5 years first for maybe a month before buying a new home so it might go to a UPS P.O. box. Besides I don’t think Kickstarter allows P.O. box shipments anyway.

And same goes for FedEx, I believe I can work with my FedEx account in the same way I would work with my UPS account.
FYI: For others, it’s free to set up an basic UPS, FedEx, and USPS account online. You may need to provide a payment card but it didn’t involve a monthly fee and you don’t need to be a company for these accounts. Well at least it was when I set these up a few years ago.

Can we get a little more details?
1. How many of the “Great Scott” meters were already shipped in the first round. How many of the 450 still need to be shipped? If it will follow backer order and I know mine is in the next 100 from Kane then I’ll just let things be.
2. How is Kane shipping to US customers? Are they using FedEx, USPS, UPS, DHL? Knowing this I can at least put some changes in place with those shippers accounts to ensure it won’t get lost.
3. Will you or Kane be sending out tracking numbers? If I have this and see it’s going to the wrong address I can have the shipper intercept it and change the packages route to the correct destination. This could happen if a Kickstarter address change doesn’t get filtered to the shipper fast enough.
4. Well #3 is based off the assumption these will have tracking numbers. I hope they do at this point because to not track and insure packages could cause more customers issues with some people. And I’m sure this will just cause more work for you also.
5. On a scale from 1 to 10, how sure are you on the May 19th start of shipping before I pay for a P.O. Box. But I will still need to know the shipper Kane uses for the best P.O. box to set or put a hold on my packed from that shipper.

I would think you would want this to go as smooth as possible from this point forward considering all the issues and delays already.

I would rather not take any more “chances” or “unknown’s” from this point going forward. I would think some of this information I’m asking to be shared wouldn’t be hard to confirm. Kane probably has a contract in place with one specific shipper for each region, so that should be easy to let us know who the shipper is, if it will have a tracking number and if it will be insured.

Scott
Title: Re: EEVBlog 121GW Discussion thread
Post by: Hugoagogo on April 29, 2018, 11:36:04 pm
I was in the original batch of a meters sold through the store, and as such cant see the updates posted to the kick-starter page, is there any way I can see these at all, or an alternate place I can read them.

Also finally got around to updating the firmware, going from V1.01 to V1.15 certainly speeds up the autoranging.
Title: Re: EEVBlog 121GW Discussion thread
Post by: firewalker on April 30, 2018, 01:34:01 am
Quote
Hi Backers

Sorry for all the delays, but we have been working through various issues that are now sorted out and we are back on track for production.

UEi are ramping back up production and calibration, and have the following dates:

- 50 units are shipping to me on the 5th May (this is an original lot of units that went into limbo at the docks - long story, but we have to account for these separately and some people are aware of these and have asked about them)

- 1000 units will be available for shipping to the various distributors on the 19th May.
(EEVblog for Aus + misc countries, Kane Test for the US, Welectron for the EU)

- Another 1000 units will be available ASAP after that.

Please note that UEi can't magically produce and calibrate thousands of units at once, and especially testing and calibration takes significant time. Current capacity is basically around the 1000 units per month figure.

The first lot of 1050 units will obviously fulfill the remainder Great Scott backers (mostly US based customers), and there will be a large number left over to start fulfilling the Johhny B. Goode backers. But which of these backers will get shipped units first I can't say, as that will depend upon exact number of units available for each distribution center, and likely the order in which you backed. There will unfortunately be a large number of Johnny B/ Goode backers who will have to wait for the next 1000 unit batch.

And please note that the above dates are NOT shipping dates to backers, they are dates when units leave the factory to the distributors. Obviously there will be extra logistical handling delays involved that are unique to each distributor. So please understand that we can't give an exact date your particular unit will be shipped, so please refrain from asking. Rest assured that the wheels are in motion and you will be shipped your unit and receive your tracking number as soon as it ships.

The EU VAT invoices for Johnny B. Goode backers will be going out shortly, and there will be a separate update for this.

I will provide further updates when actual units ship to backers.

Also, for existing backers who have their meter, v1.15 of the firmware has been released with various fixes, please update and use that firmware whenever reporting any issues, we want everyone on the latest version.

As always, the best place to follow progress and discuss things is on the EEVblog forum thread for this, Kickstarter comments is just horribly suited to discussions.

https://www.eevblog.com/forum/testgear/eevblog-121gw-discussion-thread/ (https://www.eevblog.com/forum/testgear/eevblog-121gw-discussion-thread/)

Regards

Dave.
Title: Re: EEVBlog 121GW Discussion thread
Post by: JustinD on April 30, 2018, 01:56:48 am
Hey Dave, I am ready for a refund.  I was backer #115 for great scott, early bird.  I paid in November, 2017.   Sorry man, it's just been five months after the promised date.  I will have to stick with my Fluke.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Cliff Matthews on April 30, 2018, 03:26:20 am
Hey Dave, I am ready for a refund.  I was backer #115 for great scott, early bird.  I paid in November, 2017.   Sorry man, it's just been five months after the promised date.  I will have to stick with my Fluke.
Now that's odd.. Becoming a backer before becoming a forum member  :-//
Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on April 30, 2018, 03:49:43 am
Now that's odd.. Becoming a backer before becoming a forum member  :-//

Not necessarily.  The meter caught his eye before the forum did.  I can understand that.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Hugoagogo on April 30, 2018, 09:58:32 am
Thanks Firewalker, although I probably wasn't clear enough, the copied post is public on kickstarter.

There are four locked off posts in particular I wanted to stay on top of.
- Knob and shim shimpments (I got an email saying something from the eevblog store has been shipped, but not what it is or what to do with it)
- Update on hardware on software (is there any other faults I should know about?)
- Switch contact update
- General Update
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on April 30, 2018, 12:04:06 pm
I was in the original batch of a meters sold through the store, and as such cant see the updates posted to the kick-starter page, is there any way I can see these at all, or an alternate place I can read them.

Sorry, didn't think about that.
I guess I could bulk email those original 50 people?
This thread is the best place for updates really, the Kickstarter updates are more for those who haven't gotten their meter yet.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on April 30, 2018, 12:12:26 pm
Dave,
I honestly don’t know if I will need to change my address or not based on the update email, obviously EUI should start shipping the next 1050 units. So if I understand this correctly the first 50 goes to Australia, then the next 1000 remaining EUi sends out goes to different fulfillment shippers based on the addresses in the remaining “great Scott” option? Since the “Great Scott” was only 450 I’m to assuming this supply will cover the remaining “Great Scott” supports on May 19th?

Now the question becomes if I change my address on Kickstarter how fast does this data get to EUI or the shipper like Kane for US customers and refreshed, and then passed onto Kane for the US shipper? Can we get a hard cutoff date to when the last date will be to change the address in Kickstarter?

I have already closed off the date to change address, but I guess there will always be one or two people who happen to change address after this and before shipment.
If you really ned to change your adress then send a message on Kickstarter and David will have to update your address manually.


Quote
I can’t give or know a hard date on when my address will change, if your have ever sold a house before then you know things can change at the last minute that will also change the date of the sale.

I don’t know about other country local posts but the US post office will not forward packages. The original shipping method was to be done with DHL as original mentioned in the “Great Scott” package I selected on Kickstarter. But it seems DHL isn’t handling any of these shipments now and was originally changed in the beginning also, that’s my assumption from the beginning logistics that seemed to be changed and was part of the original hold up at US customs.

I think a little more details will help me and others in my situation figure out what steps we might need to make next. For example, I have a UPS, USPS, and FedEx account. If I at least know what shipping carrier Kane will be using and the package is tracking then I may have different options to ensure I get the package without involving the Kickstarter address change.

If Kane is using USPS then my address forwarding will just screw this up. This means I need to do the Kickstarter address update and why the hard date would be useful and hope this change of address gets from Kickstarter, to Dave, then to Kane in time before it ships.

If I know Kane is using UPS for shipping then I don’t have to worry about my USPS post office forwarding and the meter package being returned, or worse case the new owner of my house keeping it. For this reason I hope these are being shipped insured?
I can work with my UPS account once I have a tracking number and request it be delivered to my new address or I can set up a UPS/or FedEx P.O Box. I would have done this already, but we never had a sure date in when shipping would continue and I couldn’t afford paying on a P.O. box since December just for this meter.

I can’t change Kickstarter to a confirmed new address since I have to sell the house first before buying a new one. And I was hoping to take a holiday that I haven’t had in 5 years first for maybe a month before buying a new home so it might go to a UPS P.O. box. Besides I don’t think Kickstarter allows P.O. box shipments anyway.

And same goes for FedEx, I believe I can work with my FedEx account in the same way I would work with my UPS account.
FYI: For others, it’s free to set up an basic UPS, FedEx, and USPS account online. You may need to provide a payment card but it didn’t involve a monthly fee and you don’t need to be a company for these accounts. Well at least it was when I set these up a few years ago.

And therein lies the problem, what if a thousand people are in the same situation? it becomes a nightmare!

Quote
Can we get a little more details?
1. How many of the “Great Scott” meters were already shipped in the first round. How many of the 450 still need to be shipped? If it will follow backer order and I know mine is in the next 100 from Kane then I’ll just let things be.

All but the US ones have shipped, so 256 US units left.

Quote
2. How is Kane shipping to US customers? Are they using FedEx, USPS, UPS, DHL? Knowing this I can at least put some changes in place with those shippers accounts to ensure it won’t get lost.

I don't know what service they are using, I will ask.

Quote
3. Will you or Kane be sending out tracking numbers? If I have this and see it’s going to the wrong address I can have the shipper intercept it and change the packages route to the correct destination. This
could happen if a Kickstarter address change doesn’t get filtered to the shipper fast enough.

Yes. Kane will send them out.

Quote
5. On a scale from 1 to 10, how sure are you on the May 19th start of shipping before I pay for a P.O. Box. But I will still need to know the shipper Kane uses for the best P.O. box to set or put a hold on my packed from that shipper.

I can't be sure of anything until it actually happens. Kane have said May 19th, but that's NOT shipping to customers it's units available from their warehouse to distributors.

I would think you would want this to go as smooth as possible from this point forward considering all the issues and delays already.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on April 30, 2018, 12:19:46 pm
Hey Dave, I am ready for a refund.  I was backer #115 for great scott, early bird.  I paid in November, 2017.   Sorry man, it's just been five months after the promised date.  I will have to stick with my Fluke.

No problem, refunded.
Title: Re: EEVBlog 121GW Discussion thread
Post by: mtdoc on April 30, 2018, 12:20:48 pm
I got an email saying something from the eevblog store has been shipped, but not what it is or what to do with it

Yep me to.  Was it the new knob and shim? 
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on April 30, 2018, 12:21:30 pm
Did any European early birds get the shim sent to them yet?  My meter dial has started to play up and I haven't received the shim.
I am still waiting for delivery. I recognize the shim problem since about 2 weeks now.

If you are one of the early birds you should have the same version as me. Can you please check something for me?

When I shorten the voltage input to com and set the 121GW to voltage AC 5V range I get a value of about 0,4999V displayed. When I open the short it is nearly the same (a little more maybe 0,5001V). In all other voltage AC or DC ranges I get 0,0xxxV when the input is shortened.

I tried to calibrate zero offset but this did not help. The last firmware (v1.15) did not too.

We suspect you might have a range switch problems causing weird stuff.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on April 30, 2018, 12:22:20 pm
I got an email saying something from the eevblog store has been shipped, but not what it is or what to do with it

Yep me to.  Was it the new knob and shim?

Yes, it was the knob and shim being shipped.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Average Meatsack on April 30, 2018, 02:30:47 pm
Does each backer get a tracking number sent to them when their meter is dispatched on the final part of the journey?
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on April 30, 2018, 03:57:49 pm
Does each backer get a tracking number sent to them when their meter is dispatched on the final part of the journey?

Yes.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Hugoagogo on April 30, 2018, 10:12:21 pm
I was in the original batch of a meters sold through the store, and as such cant see the updates posted to the kick-starter page, is there any way I can see these at all, or an alternate place I can read them.

Sorry, didn't think about that.
I guess I could bulk email those original 50 people?
This thread is the best place for updates really, the Kickstarter updates are more for those who haven't gotten their meter yet.

Is there a page anywhere where this stuff can be kept track of, maybe a pinned post? Just with a rough outline of what the issues are, what the knob fix is, and how it is installed (mine turned up today :). I t would also be nice if there was a changelog for the firmware. It is just a bit hard to keep on top of multiple 30 page threads to know whats going on.

I don't mean to be complaining, the meter has worked pretty well for me so far (even before the mechanical and software updates).
Title: Re: EEVBlog 121GW Discussion thread
Post by: kalross on May 01, 2018, 10:56:41 am
If you are one of the early birds you should have the same version as me. Can you please check something for me?

When I shorten the voltage input to com and set the 121GW to voltage AC 5V range I get a value of about 0,4999V displayed. When I open the short it is nearly the same (a little more maybe 0,5001V). In all other voltage AC or DC ranges I get 0,0xxxV when the input is shortened.

I tried to calibrate zero offset but this did not help. The last firmware (v1.15) did not too.

All measures fine when shorted on those ranges Candid.
Title: Re: EEVBlog 121GW Discussion thread
Post by: ChrisG on May 01, 2018, 03:15:53 pm
All measures fine indeed on mine too.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Candid on May 01, 2018, 07:56:34 pm
Ok so I wait for the shim and knob and will see, if the problem can be solved. Thanks for the answers.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Acecool on May 02, 2018, 02:41:29 am
So it does AC as well as DC? I read somewhere it only did DC... odd...

Where can I buy it and how long does it take to ship to USA / North Carolina?

Edit: Nevermind....

https://www.kickstarter.com/projects/eevblog/eevblog-121gw-multimeter (https://www.kickstarter.com/projects/eevblog/eevblog-121gw-multimeter)

I found that and thought ok, great $250 AU - but not available so ok $260 with free shipping.. fine I'll pay that after reviewing the features - I'd love to back this project... - I log in ... not available...

I then go to the site ( You should really add a link - ie change EEVblog Electronics Community Forum text to link to the main site as the main forum has a ton of other links with breadcrumbs )... $330 AU + tax + shipping, etc... for it and the bag... $80 more - wow..... Doesn't look like I'll be able to get it...

10 days to back or take pre-orders on a project is way too low....
Title: Re: EEVBlog 121GW Discussion thread
Post by: kalross on May 02, 2018, 08:58:02 am
Did any European early birds get the shim sent to them yet?  My meter dial has started to play up and I haven't received the shim.

I've had no notification of shipping of shim yet...was early bird backer...Dec 2017

Ta.

K
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on May 02, 2018, 09:02:05 am
10 days to back or take pre-orders on a project is way too low....

And no matter how long I left there will be people still complaining they missed the Kickstarter.
And it's not like I didn't announce it in a video, on this forum, on Twitter, on Facebook, on my blog etc.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on May 02, 2018, 01:52:21 pm
10 days to back or take pre-orders on a project is way too low....

And no matter how long I left there will be people still complaining they missed the Kickstarter.
And it's not like I didn't announce it in a video, on this forum, on Twitter, on Facebook, on my blog etc.

As it was, the support for the Kickstarter campaign resulted in AU$ 644,674 pledged of AU$ 42,000 goal.  Just slightly over-achieving (by a factor of 15!).

Was someone hoping you'd hit the AU$ 1,000,000 ?!!
Title: Re: EEVBlog 121GW Discussion thread
Post by: geekGee on May 02, 2018, 02:43:14 pm
10 days to back or take pre-orders on a project is way too low....

I would say that 2,300 individuals thought 10 days was more than long enough to back the project.

I thought it was too long... I patiently held off until near the end, to hopefully avoid some of the initial product "teething" pains with a later shipment, so it was a long near 10 day wait to pull the trigger.  ;)
Title: Re: EEVBlog 121GW Discussion thread
Post by: Iagash on May 03, 2018, 06:05:32 am
Update has been released to the app stores, likely hasn't updated on both yet but these issues should all be resolved now, we also have a new firmware version which will be resolving one of the other issues (when the voltage in VA mode is above 32767 approximately, this firmware update hasn't been released, this issue was a packet issue not a app issue so for those values you'll need to wait for the next firmware update).

Would you please push your app changes to the gitlab repo as I suspect the RangeLookup table in Packet121GW.cs has changed. I'd like to add your changes to my script.

Thanks!

Hi Seppy,

ping :-)

Is there a chance that you update the gitlab repo?
I'd like to see how you did solve the subdisplay range in [m]VA mode.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Seppy on May 03, 2018, 11:14:39 am
Update has been released to the app stores, likely hasn't updated on both yet but these issues should all be resolved now, we also have a new firmware version which will be resolving one of the other issues (when the voltage in VA mode is above 32767 approximately, this firmware update hasn't been released, this issue was a packet issue not a app issue so for those values you'll need to wait for the next firmware update).

Would you please push your app changes to the gitlab repo as I suspect the RangeLookup table in Packet121GW.cs has changed. I'd like to add your changes to my script.

Thanks!

Hi Seppy,

ping :-)

Is there a chance that you update the gitlab repo?
I'd like to see how you did solve the subdisplay range in [m]VA mode.

Sorry haven't been able to update the git for a little while, I need to be entirely sure none of the app store details are included in the GIT repo.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Oldschool_tech on May 04, 2018, 03:13:28 pm
Hi, First time on the forum.  Dave and all, I have 121GW serial number 000168. Saw an email regarding the dispatch of the "Knob and shim kit" several weeks ago. Still nothing has arrived per Australia Post. Any way of tracking ?

Very happy with the meter. Purchased my first digital meter "AVO 2001" in 1984, and have various Flukes and a Tektronix TX3.

The minor issues with firmware should soon be resolved, I'm sure.
Title: Re: EEVBlog 121GW Discussion thread
Post by: cmumford on May 04, 2018, 11:34:52 pm
The minor issues with firmware should soon be resolved, I'm sure.

Hey Oldschool: Have you installed firmware v1.15?
Title: Re: EEVBlog 121GW Discussion thread
Post by: Oldschool_tech on May 05, 2018, 07:41:47 am
Yes I have v 1.15 installed. I have not had issues. Can't say that I have used meter extensively. But I meant that at least if an issue is detected and resolved, the firmware is easy to upgrade. I have had the switch play up. The 3V / 15V diode test function I find particularly handy.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Ahaber on May 07, 2018, 04:11:02 pm
I need to change my shipping address, but the survey is showing as closed on kickstarter. How can I go about doing this?
Title: Re: EEVBlog 121GW Discussion thread
Post by: plexus on May 08, 2018, 08:23:31 am
I got the shim kit today. Thanks Daves. Installed and working fine. I wasn't really having too much trouble with the original knob but this one feels better, tigher, confidence building.

Any ETA on the iOS bluetooth app? Since the one in the app store has stopped working with the firmware updates, I miss having the remote capability which was a top-3 reason I got the 121GW. I have am going to have to downgrade back to 1.07 and hope I can use the original app until you guys release an up to date one.

Did you really have to break the iOS app with the firmware update?
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on May 08, 2018, 09:45:53 am
Did you really have to break the iOS app with the firmware update?

Yes, we did have to, sorry, for reasons of comms integrity.
BTW, the iOS is not "ours", i.e. EEVblog's, it is UEI's app.
Title: Re: EEVBlog 121GW Discussion thread
Post by: plexus on May 08, 2018, 10:21:12 am
Did you really have to break the iOS app with the firmware update?

Yes, we did have to, sorry, for reasons of comms integrity.
BTW, the iOS is not "ours", i.e. EEVblog's, it is UEI's app.

Yes I knew that the one in the iOS app store is UEI's not yours. Ok.. well hopefully you will get an iOS app out soon!
Title: Re: EEVBlog 121GW Discussion thread
Post by: fanOfeeDIY on May 11, 2018, 03:27:50 am
I received the new rotary switch and shim for 121GW multimeter.
I took a video of before and after of changing them.

https://youtu.be/nL7wDFNH8hM
Title: Re: EEVBlog 121GW Discussion thread
Post by: plexus on May 11, 2018, 03:31:36 am
I received the new rotary switch and shim for 121GW multimeter.
I took a video of before and after of changing them.

Yes... do not remove the 4 small silver-capped screws on the top part of the back of the board - these hold the display down and there is no need to remove them or the display. It's a bit of a risk if you do remove the display because murphy's law can come into play.  :phew:
Title: Re: EEVBlog 121GW Discussion thread
Post by: fanOfeeDIY on May 11, 2018, 11:24:40 am
I received the new rotary switch and shim for 121GW multimeter.
I took a video of before and after of changing them.

Yes... do not remove the 4 small silver-capped screws on the top part of the back of the board - these hold the display down and there is no need to remove them or the display. It's a bit of a risk if you do remove the display because murphy's law can come into play.  :phew:

I completely understand it after I have de-soldered and soldered the LCD :)
The soldering joins are very thin.

I will probably never remove it again. I want my 121GW to last long.
Title: Re: EEVBlog 121GW Discussion thread
Post by: iainwhite on May 11, 2018, 10:06:01 pm
I got my packet with the new range switch but no yellow shim.    :(
Title: Re: EEVBlog 121GW Discussion thread
Post by: Candid on May 11, 2018, 10:45:21 pm
Lucky man, I got no shim and no switch up to now ;-)
Title: Re: EEVBlog 121GW Discussion thread
Post by: 1anX on May 12, 2018, 06:38:48 am
I got my packet with the new range switch but no yellow shim.    :(
Your not the first to report this!
Who is sending these kits out incomplete Dave?
Title: Re: EEVBlog 121GW Discussion thread
Post by: prof on May 13, 2018, 09:09:04 am
Received my (complete) kit today and replaced the switch. It's a bit finicky and the instructions are a bit confusing (like ensuring the proper alignment of the mechanics in the step before actually handling it or explaining to remove the fuse rather in the beginning though in retrospect it doesn't seem to be required at all?) but the results are really surprisingly different even though I wouldn't have considered the old behaviour a problem...  ;D
Title: Re: EEVBlog 121GW Discussion thread
Post by: mtdoc on May 13, 2018, 10:32:50 am
Funally got my knob snd shim, but no instructions. Are they posted somewhere?
Title: Re: EEVBlog 121GW Discussion thread
Post by: IanB on May 13, 2018, 11:04:36 am
Funally got my knob snd shim, but no instructions. Are they posted somewhere?

121GW knob installation replace rotary switch instructions

https://youtu.be/Kok7VJft3vs (https://youtu.be/Kok7VJft3vs)

http://www.eevblog.com/files/How%20to%20Replace%20121GW%20Rotary%20Switch-180411.pdf (http://www.eevblog.com/files/How%20to%20Replace%20121GW%20Rotary%20Switch-180411.pdf)
Title: Re: EEVBlog 121GW Discussion thread
Post by: bitwelder on May 13, 2018, 05:18:43 pm
About the instructions:
http://www.eevblog.com/files/How%20to%20Replace%20121GW%20Rotary%20Switch-180411.pdf (http://www.eevblog.com/files/How%20to%20Replace%20121GW%20Rotary%20Switch-180411.pdf)

Step 12 reads:
Quote
12) Make sure that the 3 PTCs are lined up in a row.
Just curious, have been cases of bent PTCs or why the note? Simple basic precaution?
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on May 16, 2018, 06:36:29 pm
Update coming on KS today.
All Great Scott US backers have now been shipped. If anyone in the US can post a photo of the packaging then we'd be curious to see it. Thanks.

Other remaining Great Scott backers also shipped, so that's all of them now  :phew:
Title: Re: EEVBlog 121GW Discussion thread
Post by: jgm84 on May 16, 2018, 06:46:31 pm
EDIT: I received the Kickstarter update after posting this message. Now that it's clear everything is legit I will proceed with the payment. Thank you!
---
Just curious, is the update related to the Johnny B. Goode backers in Europe? I got a Paypal invoice today for something that seems to be the import VAT for Europe, but it does look a bit suspicious. I would like to have some official confirmation before I put the payment through.
Title: Re: EEVBlog 121GW Discussion thread
Post by: ding on May 16, 2018, 07:58:59 pm
I'm an EU JBG backer and I can't see a paypal invoice, not sure if its a PEBKAC or not but everything looks ok on the kickstarter survey, anyone else in the same boat? :-//
Title: Re: EEVBlog 121GW Discussion thread
Post by: SmudgerD on May 16, 2018, 09:11:51 pm
I'm an EU JBG backer and I can't see a paypal invoice, not sure if its a PEBKAC or not but everything looks ok on the kickstarter survey, anyone else in the same boat? :-//

Same here. Dave's update said we should have received a PayPal invoice today implying that the PayPal invoices went out before the Kickstarter update, but I haven't seen a PayPal invoice yet.

SmudgerD
Title: Re: EEVBlog 121GW Discussion thread
Post by: firewalker on May 16, 2018, 10:19:57 pm
I received my invoice 4 hours ago.

Alexander.
Title: Re: EEVBlog 121GW Discussion thread
Post by: jordanp123 on May 16, 2018, 10:20:49 pm
Haven't received my shipment notification yet (USA), but I'll just wait for it to come in for a few days, then ask for tracking if it doesn't show.
Title: Re: EEVBlog 121GW Discussion thread
Post by: pa3weg on May 16, 2018, 11:38:33 pm
Outta luck!
Paypal does not allow guest checkout in the Netherlands |O
guess I will have to risk it with customs and possible have a hefty fee applied.

Before anyone asks, no I do not want a PayPal account and no, I will not give my phone number, as it is not essential to the process
Title: Re: EEVBlog 121GW Discussion thread
Post by: IanB on May 16, 2018, 11:54:15 pm
Update coming on KS today.
All Great Scott US backers have now been shipped. If anyone in the US can post a photo of the packaging then we'd be curious to see it. Thanks.

Other remaining Great Scott backers also shipped, so that's all of them now  :phew:

Just for info, I have not received a shipping notification or tracking number. How long should I wait before querying this?
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on May 17, 2018, 12:08:26 am
Update coming on KS today.
All Great Scott US backers have now been shipped. If anyone in the US can post a photo of the packaging then we'd be curious to see it. Thanks.

Other remaining Great Scott backers also shipped, so that's all of them now  :phew:

Just for info, I have not received a shipping notification or tracking number. How long should I wait before querying this?

Given the number of Great Scott backers on KS comments saying they haven't received a tracking number, it seems I may interpreted wording wrongly from Kane that they had all been shipped and emails sent. Checking on that now, should hear back tomorrow.
Title: Re: EEVBlog 121GW Discussion thread
Post by: jordanp123 on May 17, 2018, 12:09:56 am
Got my tracking number in the last 5 minutes. FedEx.
Title: Re: EEVBlog 121GW Discussion thread
Post by: synapsis on May 17, 2018, 12:44:54 am
US Great Scott backer 435, no tracking.

And Kickstarter doesn't seem the recognize the email I used to back the project, so this is the only way I can comment. :(

My BM235 is still cranking along, though!
Title: Re: EEVBlog 121GW Discussion thread
Post by: ChunkyPastaSauce on May 17, 2018, 01:14:52 am
Got my tracking number in the last 5 minutes. FedEx.

Just received a fedex tracking number 30 mins ago as well  (from 121gwdonotreply@gmail.com)

Fedex can't find it though:

Code: [Select]
Not found
This tracking number cannot be found, please check the number or contact the sender.
Title: Re: EEVBlog 121GW Discussion thread
Post by: dr.diesel on May 17, 2018, 01:17:51 am
Got my tracking number in the last 5 minutes. FedEx.

Just received a fedex tracking number 30 mins ago as well  (from 121gwdonotreply@gmail.com)

Fedex can't find it though:

Code: [Select]
Not found
This tracking number cannot be found, please check the number or contact the sender.

Has to actually be scanned at a FedEx location to show up on their site, you probably got the email when the shipping invoice was created.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Scottjd on May 17, 2018, 01:41:07 am
Got my tracking number in the last 5 minutes. FedEx.
Ok, so is it safe to say US backers are receiving the meters with FedEx shipping?
Title: Re: EEVBlog 121GW Discussion thread
Post by: Bratster on May 17, 2018, 01:48:19 am
Got my FedEx tracking at 7:47a PST.

Sent from my Moto x4 using Tapatalk

Title: Re: EEVBlog 121GW Discussion thread
Post by: Scottjd on May 17, 2018, 01:54:03 am
Got my FedEx tracking at 7:47a PST.

Sent from my Moto x4 using Tapatalk
Great (Scott),
Can you induced anything from the email. Like and first sentence line. Or the email domain it was sent from.
This way other and I can search our inbox for this first sentence to make sure it wasn’t filtered to another folder.
Don’t include you shipping # or any personal information for your privacy.
Thanks,
Scott
Title: Re: EEVBlog 121GW Discussion thread
Post by: Bratster on May 17, 2018, 02:00:18 am
Got my FedEx tracking at 7:47a PST.

Sent from my Moto x4 using Tapatalk
Great (Scott),
Can you induced anything from the email. Like and first sentence line. Or the email domain it was sent from.
This way other and I can search our inbox for this first sentence to make sure it wasn’t filtered to another folder.
Don’t include you shipping # or any personal information for your privacy.
Thanks,
Scott
Subject: 121gw tracking
Sender name: eevblog 121gw
Sender email: 121gwdonotreply@gmail.com
Message body: HELLO YOUR 121GW METER IS SHIPPING VIA FEDEX HERE IS YOUR TRACKING NUMBER: 

Sent from my Moto x4 using Tapatalk

Title: Re: EEVBlog 121GW Discussion thread
Post by: Scottjd on May 17, 2018, 02:06:52 am
Got my FedEx tracking at 7:47a PST.

Sent from my Moto x4 using Tapatalk
Great (Scott),
Can you induced anything from the email. Like and first sentence line. Or the email domain it was sent from.
This way other and I can search our inbox for this first sentence to make sure it wasn’t filtered to another folder.
Don’t include you shipping # or any personal information for your privacy.
Thanks,
Scott
Subject: 121gw tracking
Sender name: eevblog 121gw
Sender email: 121gwdonotreply@gmail.com
Message body: HELLO YOUR 121GW METER IS SHIPPING VIA FEDEX HERE IS YOUR TRACKING NUMBER:

Sent from my Moto x4 using Tapatalk

Thank you, that’s. Great help.
Well I wouldn’t delete an email with that subject, md for search box works with the submit I get Kickstarter update #24, 22, and 21 from April to May. So maybe they are still sending them out.
What backer # are you?
Thanks again,
Scott
Title: Re: EEVBlog 121GW Discussion thread
Post by: Bratster on May 17, 2018, 03:25:40 am
Got my FedEx tracking at 7:47a PST.

Sent from my Moto x4 using Tapatalk
Great (Scott),
Can you induced anything from the email. Like and first sentence line. Or the email domain it was sent from.
This way other and I can search our inbox for this first sentence to make sure it wasn’t filtered to another folder.
Don’t include you shipping # or any personal information for your privacy.
Thanks,
Scott
Subject: 121gw tracking
Sender name: eevblog 121gw
Sender email: 121gwdonotreply@gmail.com
Message body: HELLO YOUR 121GW METER IS SHIPPING VIA FEDEX HERE IS YOUR TRACKING NUMBER:

Sent from my Moto x4 using Tapatalk

Thank you, that’s. Great help.
Well I wouldn’t delete an email with that subject, md for search box works with the submit I get Kickstarter update #24, 22, and 21 from April to May. So maybe they are still sending them out.
What backer # are you?
Thanks again,
Scott
I'm in the 100 to 200 range.

Edit: tracking now shows as label created. Should be here next week. :-)

Sent from my Moto x4 using Tapatalk
Title: Re: EEVBlog 121GW Discussion thread
Post by: nickdepinet on May 17, 2018, 04:03:55 am
I got that email yesterday, FedEx shows it currently on the way. Looks like kane is sending them out
Title: Re: EEVBlog 121GW Discussion thread
Post by: ChunkyPastaSauce on May 17, 2018, 06:47:44 am
Got my tracking number in the last 5 minutes. FedEx.

Just received a fedex tracking number 30 mins ago as well  (from 121gwdonotreply@gmail.com)

Fedex can't find it though:

Code: [Select]
Not found
This tracking number cannot be found, please check the number or contact the sender.

Has to actually be scanned at a FedEx location to show up on their site, you probably got the email when the shipping invoice was created.

Tracking info now showing, label generated, estimated delivery for tomorrow (based on shipping today).
Title: Re: EEVBlog 121GW Discussion thread
Post by: VinzC on May 17, 2018, 06:48:54 am
@Dave

I have indeed received the Paypal note for the EU VAT invoice. (I'm on the Johnny B. Goode batch.) However I can't seem to be able to pay via Paypal; the Australian (not Austrian) version allows me to pay without creating an account (which I of course *do* want), unfortunately after selecting my country and language, I'm taken by the balls and have to create an account... :wtf: screw them, I f*** hate that!  :--

Instead I could either pay the VAT by bank transfer (this is the term I'm used to with Digi-Key when not using a credit card), for which I'd need a bank account number (though I might have to pay more but I just don't care) or... I also use to pay the remaining taxes upon delivery to the driver, so if it's a possibility, so be it. Send cash inside an envelope? Why not. Name your price.

And thanks again for this work.
Title: Re: EEVBlog 121GW Discussion thread
Post by: rstofer on May 17, 2018, 12:39:38 pm
Great Scott!  US customer.  I have a Fedex tracking number and the unit is to be delivered Friday 5/18.  The package is actually in transit.

I didn't know how to reply to Dave's Kickstarter query re: having tracking numbers so here I am.
Title: Re: EEVBlog 121GW Discussion thread
Post by: PeterL on May 17, 2018, 06:08:19 pm
@Dave

I have indeed received the Paypal note for the EU VAT invoice. (I'm on the Johnny B. Goode batch.) However I can't seem to be able to pay via Paypal; the Australian (not Austrian) version allows me to pay without creating an account (which I of course *do* want), unfortunately after selecting my country and language, I'm taken by the balls and have to create an account... :wtf: screw them, I f*** hate that!  :--

Instead I could either pay the VAT by bank transfer (this is the term I'm used to with Digi-Key when not using a credit card), for which I'd need a bank account number (though I might have to pay more but I just don't care) or... I also use to pay the remaining taxes upon delivery to the driver, so if it's a possibility, so be it. Send cash inside an envelope? Why not. Name your price.

And thanks again for this work.
O c'mon Because you don't want to sign up with paypal Dave has to bend in seven ways to give a solution that suits you? Remember that this is already goodwill from Dave. If you don't like it just pay the mailman.
Title: Re: EEVBlog 121GW Discussion thread
Post by: ChrisG on May 17, 2018, 08:50:34 pm
Having my 121GW since many months now. The issue with the range switch is getting worse. Anxiously awaiting the new range switch and shim. So far no news in my email or normal postal inbox. Any people in Europe received the new range switch and shim? I noticed some German 121GW users on this thread?
Title: Re: EEVBlog 121GW Discussion thread
Post by: tcottle on May 18, 2018, 12:23:45 am
I'm a Great Scott backer (#260) and just received a e-mail with a tracking number.  W00t!   Tracking shows that it is shipping from Indianapolis
Title: Re: EEVBlog 121GW Discussion thread
Post by: VinzC on May 18, 2018, 01:15:11 am
@Dave

I have indeed received the Paypal note for the EU VAT invoice. (I'm on the Johnny B. Goode batch.) However I can't seem to be able to pay via Paypal; the Australian (not Austrian) version allows me to pay without creating an account (which I of course *do* want), unfortunately after selecting my country and language, I'm taken by the balls and have to create an account... :wtf: screw them, I f*** hate that!  :--

Instead I could either pay the VAT by bank transfer (this is the term I'm used to with Digi-Key when not using a credit card), for which I'd need a bank account number (though I might have to pay more but I just don't care) or... I also use to pay the remaining taxes upon delivery to the driver, so if it's a possibility, so be it. Send cash inside an envelope? Why not. Name your price.

And thanks again for this work.
O c'mon Because you don't want to sign up with paypal Dave has to bend in seven ways to give a solution that suits you? Remember that this is already goodwill from Dave. If you don't like it just pay the mailman.
Where did I write Dave has to "bend"?  :palm: Does asking a question imply that the answer is Dave has to... damn'... I don't even follow your logic. If Dave doesn't agree, he can always say "no" which, if you read me again, is part of the (open) option list I gave — damn! why do I have to justify myself in the first place?

I for one just don't want to "bend" (to quote your terms) before Paypal — why are Australians allowed to pay without creating an account and Belgians not? Hmm?

I'm not *demanding* Dave to satisfy me and fix Paypal's lack of features for me, I'm just *asking (if)*, see the difference? Neither do I ask you to comment my reasons, for which you have absolutely no clue. So please stop criticizing me for asking.

Only the last part of your sentence is relevant:
If you don't like it just pay the mailman.
I suppose you're replying in Dave's behalf, right >:D ?

Tip: no need to think you've got to give lessons and ride your high horse. I don't criticize your choices (which I don't care) so don't criticize mine. Thanks for the info, by the way.
Title: Re: EEVBlog 121GW Discussion thread
Post by: DaJMasta on May 18, 2018, 01:35:06 am
I'm a Great Scott backer (#260) and just received a e-mail with a tracking number.  W00t!   Tracking shows that it is shipping from Indianapolis

Also got mine, number 269, with the same details.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Scottjd on May 18, 2018, 06:03:40 am
I'm a Great Scott backer (#260) and just received a e-mail with a tracking number.  W00t!   Tracking shows that it is shipping from Indianapolis

Also got mine, number 269, with the same details.
I received my tracking number today, backer 274 in the US. It say expected deliver Friday, but today is Thursday and the label still states it is only printed I have my doubts for a Friday delivery. Since FedEx doesn’t work on weekends I might see this Monday or Tuesday of next week. Seems that US Kane shipment are going in order of the backing numbers.
Scott
Title: Re: EEVBlog 121GW Discussion thread
Post by: benst on May 18, 2018, 06:13:23 am
I got the replacement knob & shim and installed them just now. What a difference, feels much better, no more wiggling, and as far as I can tell the wonky display problems are gone.  :-DMM  :-+

Ben
Title: Re: EEVBlog 121GW Discussion thread
Post by: jordanp123 on May 18, 2018, 08:33:50 am
Got my meter in today (USA), arrived in perfect working order.
Title: Re: EEVBlog 121GW Discussion thread
Post by: ChrisG on May 18, 2018, 05:58:57 pm
Received the knob and the shim. It fits indeed. But knob is pretty if not super tight now and requires some force to turn, one hand turn with the stand unfolded is no way possible anymore. ::) Indeed no more display/power on issues anymore. I hope for you all and especially the newly shipped ones all is fine and smooth.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Scottjd on May 18, 2018, 08:35:32 pm
I received my tracking number today, backer 274 in the US. It say expected deliver Friday, but today is Thursday and the label still states it is only printed I have my doubts for a Friday delivery. Since FedEx doesn’t work on weekends I might see this Monday or Tuesday of next week. Seems that US Kane shipment are going in order of the backing numbers.
Scott

They must be shipping these meters overnight express. So I received the label tracking email yesterday at 9am EDT, then it was picked up by FedEx at 4pm EDT and didn’t get to FedEx until 9pm. I figured being picked up at the end of the day Thursday their is no way it will make it by Friday. To my surprise it went back out at 1am, was in the Ohio central main hub at 3:30am, went back out and made it to the Columbus Distribution center at 4:39am and was on the truck out for delivery at 4:45am.
That’s some major hustling, I know it’s only from Indiana to Ohio, but I’ve never seen FedEx move this fast unless it’s overnight shipping. Well it looks like I might get it in time for the weekend to play with.

So did Kane decide to overnight them to try and make up some time on having to hold them and fix the PCB manufacturing mistake?
Scott
Title: Re: EEVBlog 121GW Discussion thread
Post by: IanB on May 19, 2018, 12:45:20 am
So did Kane decide to overnight them to try and make up some time on having to hold them and fix the PCB manufacturing mistake?

No. FedEx Ground. Mine is in the middle of a long road journey and won't arrive until next week.
Title: Re: EEVBlog 121GW Discussion thread
Post by: tcottle on May 19, 2018, 01:17:06 am
Confirming shipment is FedEx Ground.  The meter has left Indy and on its way to Colorado.  Scheduled delivery on Tuesday  :-+
Title: Re: EEVBlog 121GW Discussion thread
Post by: DaJMasta on May 19, 2018, 01:17:54 am
Indiana to Maryland shipped on Thursday isn't expected to arrive until Monday, definitely ground service, but when you're close enough to the shipper the times can be pretty quick, even if they aren't always.
Title: Re: EEVBlog 121GW Discussion thread
Post by: prof on May 19, 2018, 01:44:15 am
Having my 121GW since many months now. The issue with the range switch is getting worse. Anxiously awaiting the new range switch and shim. So far no news in my email or normal postal inbox. Any people in Europe received the new range switch and shim? I noticed some German 121GW users on this thread?

Yes, see quite a few posts ago on this thread.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Photoman on May 19, 2018, 03:44:44 am
Received my meter today, FedEx ground from IN!
Title: Re: EEVBlog 121GW Discussion thread
Post by: Nerull on May 19, 2018, 07:42:25 am
Got mine today. Just FYI, this meter has the same issue with right angle Probemaster leads that Fluke meters do - the black lead (though it may vary by batch) of my micro-tip leads doesn't quite fit, though I can get it in further than my Fluke 87. AFAIK only the right angle banana plug models do this, the straight ones are fine.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Scottjd on May 19, 2018, 02:03:47 pm
So did Kane decide to overnight them to try and make up some time on having to hold them and fix the PCB manufacturing mistake?

No. FedEx Ground. Mine is in the middle of a long road journey and won't arrive until next week.
Thanks, I was able to confirm ground when I tripped over the box today arround 2pm.
Took my who day plans out of wack now. I just had to open it.
Scott
Title: Re: EEVBlog 121GW Discussion thread
Post by: JonM on May 19, 2018, 03:13:29 pm
Got mine today. Just FYI, this meter has the same issue with right angle Probemaster leads that Fluke meters do - the black lead (though it may vary by batch) of my micro-tip leads doesn't quite fit, though I can get it in further than my Fluke 87. AFAIK only the right angle banana plug models do this, the straight ones are fine.

My 121GW arrived on Thursday via FedEx.

I have tried three different sets of right angle Probemaster probes with no problem.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Scottjd on May 19, 2018, 03:46:33 pm
Got mine today. Just FYI, this meter has the same issue with right angle Probemaster leads that Fluke meters do - the black lead (though it may vary by batch) of my micro-tip leads doesn't quite fit, though I can get it in further than my Fluke 87. AFAIK only the right angle banana plug models do this, the straight ones are fine.

My 121GW arrived on Thursday via FedEx.

I have tried three different sets of right angle Probemaster probes with no problem.
I use the probemasters with the retractable shrouding and don’t have any issues with any of the meters including the 121GW or my Fluke. It also makes it good to be able and use the probes on power supplies in a pinch when you need one more cable since it retracts and they are two years old.

I do have an issue with the new Brymen black probe that came with the 121GW. It’s way to tight in all my meters, but the BM235 probes are ok, and so was the red one. I think it’s a faulty probe and just need to be replaced.

I would check you batteries, mine were shoved in fast and the negative springs were bent on 3 out of 4 of the batteries. You can remove the battery, bend the spring downwards with a little pressure and put the battery back. Hopefully over some time the spring with restore and retain it intended position.

Title: Re: EEVBlog 121GW Discussion thread
Post by: emece67 on May 19, 2018, 06:46:44 pm
Hi all,

I arrived really late to this, so I've missed many things and, although I have read the whole thread, I still have doubts about how to get one of this meters. As I understand, the EU distributor is Welectron but, must I contact them for and order or wait instead for the next (if any) kickstarter campaign? Will there be more kickstarter campaigns at all?

Thanks & regards.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Candid on May 19, 2018, 07:03:26 pm
I too don't have any problems with my probemaster right angle probes on my Fluke, 121GW and any other meter.

I had the same problem with the bended springs and the contacts falling out of the case of the battery compoundment. But this can be corrected. The springs I think are to long and the fastening hooks of the contacts are to soft so that they do not hold well in the compound over time after the batteries are in again. Just keep an eye on it when opening the compound.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Scottjd on May 19, 2018, 08:28:16 pm
I too don't have any problems with my probemaster right angle probes on my Fluke, 121GW and any other meter.

I had the same problem with the bended springs and the contacts falling out of the case of the battery compoundment. But this can be corrected. The springs I think are to long and the fastening hooks of the contacts are to soft so that they do not hold well in the compound over time after the batteries are in again. Just keep an eye on it when opening the compound.
Yes, I agree. The springs are to long and to soft. If you look at it closely it’s a cheap 4AA battery box they just out into the back of the meter molding. It’s nkt even part of the original molding. I guess this was a cheaper way to go then making the battery box part of the molding?
Scott
Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on May 20, 2018, 12:36:36 am
Took my who day plans out of wack now. I just had to open it.
Scott

You're just making excuses...

No, wait ...

Yeah I'd do that too.   :-[
You're good   :-+
Title: Re: EEVBlog 121GW Discussion thread
Post by: iainwhite on May 20, 2018, 01:27:33 am
Yes, I agree. The springs are too long and too soft.

I had noticed this - one of my springs is bent over double.  I was thinking about trimming them down to about 2/3rd of their present length.
Title: Re: EEVBlog 121GW Discussion thread
Post by: prof on May 20, 2018, 01:38:05 am
I would check you batteries, mine were shoved in fast and the negative springs were bent on 3 out of 4 of the batteries. You can remove the battery, bend the spring downwards with a little pressure and put the battery back. Hopefully over some time the spring with restore and retain it intended position.

Same here but I'm not to worried about the springies. I think the compartment is too tight for the chosen springs which is why they tend to bend.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Jon.C on May 20, 2018, 11:38:18 pm
new video from Gadget Review Videos


https://youtu.be/50M4nMMvopU (https://youtu.be/50M4nMMvopU)
Title: Re: EEVBlog 121GW Discussion thread
Post by: JonM on May 21, 2018, 05:21:11 am
Hi all,

I arrived really late to this, so I've missed many things and, although I have read the whole thread, I still have doubts about how to get one of this meters. As I understand, the EU distributor is Welectron but, must I contact them for and order or wait instead for the next (if any) kickstarter campaign? Will there be more kickstarter campaigns at all?

Thanks & regards.

The supply of  the 121GW is currently constrained and the pre-orders need to be fulfilled first. I'm sure that they will at least show up in the EEVblog Store when stock is available. Maybe available on Amazon in some countries as well.

Title: Re: EEVBlog 121GW Discussion thread
Post by: Scottjd on May 21, 2018, 06:31:44 am
new video from Gadget Review Videos
Jon, thanks for the post.
I just want to be clear this is not a review as stated in the description and text in red at the beginning of the video. This was far from planned, just a fast edit to break the monotony from the other videos I’ve been working on. It’s just a quick unboxing and initial thoughts. I mention this because of all the dislikes. If your waiting for a review then please wait a few more weeks, or maybe longer depending on different factors with life in general taking up my time.
My policy has always been to use the product for at least 2 to 4 weeks before doing my review. I do this so I know the product I’m reviewing and try not to miss anything, and this way I also know that I trust and like the product I’m reviewing. I’ve only done one video amendment from missing a bug on the original review to date.

I realize when my videos get posted on other sites and that not all the viewers know me, or know my style of doing things. I’ll try to explain this for new people that have not seen my videos in the past. I’ve debated on starting my own thread on EEVBlog like Joe Smith and his great videos and thread support. I just don’t have the time to answer questions or follow a thread like he does. I do try to answer all comments on the YouTube video, so if you have any questions or constructive feedback leave a comment. I try to help others the best I can and when I can.

My lab is my hobby that I’ve built up over time, although sometimes mistaken for a professional lab or repair shop I have never claimed to be a EE or do repairs for money. I try to keep my reviews to just the facts, my opinion, and personal experiance using the product to help people decide if it’s something that will fit their needs and something they would want to buy.
My logic in what I review is simple, if it’s not something I would use or recommend/buy for family member or a friend then I don’t review it.
I try to stay away from negative reviews.  A negative review based on a software bug that can be fixed with a firmware update in the future can hurt the company, even once the issue is corrected. And since videos on YouTube stay around forever this could still affect the company after the issue is fixed. I might release a video that might seem like a negative review, but it’s more of a public service announcement that probably concerns the safety of a person or a video showing a bug so it can be fixed. Once and if it’s fixed at a later date then I will delete the video, or change the title from a “PSA” to “Recalled Safety” and update the video description.

Reviews, testing, video recordings, editing videos all take time and I can’t always do a professional video.  I’m a one man shop that does videos as a second hobby and I’m currently juggling three other review edits.
Amazon and other links in the videos description are for the viewers convenience to find the product. These are not affiliate links and I don’t get paid for them. I removed all ads from my videos despite meeting YouTube’s minimum requirements for monetization. I don’t ask for donations or use patreon. This YouTube channel and the items I review, cameras, microphone equipment, video editing software is 97% paid by me despite being on a limited budget. A few items are occasionally donated and they have to agree to mt strict terms. If the item is donated I will mention this in the video. I try not to accept free items since it makes the review look biased and paid for.
I have tested pre-production products also, but I dint do videos until the product is officially released. I do this to give feedback and help find bugs. Sometimes I don’t release the review until a new firmware fix is released. This helps make products better for the consumer when it’s released. A few pre-production items I’ve tested have also included a product review. Most pre-production units don’t get reviewed since this is not the reason they contacted me.
Free items I’m offered (more then you may realize) are usually ignored with a few exceptions. If I think its something people want to see reviewed and they agree to my terms in advance like “Having NO say over the final review” then I might make an exception. If they don’t agree, then I will not  accept the product. If they still ship it without agreeing to my terms then I assume by default they agree to an open and honest review. Just because it was shipped to me does not guarantee a product review.
Thanks,
Scott
Title: Re: EEVBlog 121GW Discussion thread
Post by: IanB on May 21, 2018, 06:43:25 am
I mention this because of all the dislikes.

I'm not sure why there would be so many dislikes. I watched the video and it seemed fine. Some people just like to hate I guess.

You did point out a few issues from your inspection, and maybe that upset people who wanted the meter to be perfect. But that's not your fault, and no reason to dislike the video.

I notice you didn't open the battery cover and look at the battery springs. How did they look, in terms of fit and finish?
Title: Re: EEVBlog 121GW Discussion thread
Post by: Scottjd on May 21, 2018, 07:22:33 am
I mention this because of all the dislikes.

I'm not sure why there would be so many dislikes. I watched the video and it seemed fine. Some people just like to hate I guess.

You did point out a few issues from your inspection, and maybe that upset people who wanted the meter to be perfect. But that's not your fault, and no reason to dislike the video.

I notice you didn't open the battery cover and look at the battery springs. How did they look, in terms of fit and finish?
I actually mentioned this in a different thread I think? The springs were folded over and pinched so I did recommend on a post to look at the new meters batteries and try to bend the springs down and put them back into alignment.  I know everything is going modular these days but it looks like the back battery molding was separate from the battery case, as if the battery case was a module that was just put into square placeholder on the back molding.
Title: Re: EEVBlog 121GW Discussion thread
Post by: IanB on May 21, 2018, 08:13:09 am
I actually mentioned this in a different thread I think? The springs were folded over and pinched so I did recommend on a post to look at the new meters batteries and try to bend the springs down and put them back into alignment.  I know everything is going modular these days but it looks like the back battery molding was separate from the battery case, as if the battery case was a module that was just put into square placeholder on the back molding.

I forgot if it was you who mentioned it. I was just curious to see what the battery compartment and springs looked like on video.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Scottjd on May 21, 2018, 09:04:32 pm
I actually mentioned this in a different thread I think? The springs were folded over and pinched so I did recommend on a post to look at the new meters batteries and try to bend the springs down and put them back into alignment.  I know everything is going modular these days but it looks like the back battery molding was separate from the battery case, as if the battery case was a module that was just put into square placeholder on the back molding.

I forgot if it was you who mentioned it. I was just curious to see what the battery compartment and springs looked like on video.
Unfortunately I didn’t have a camera rolling when I looked at this. I guess I didn’t expect that with the batteries. Seems like a simple old tech on how batteries are held into something. The only time I’ve had to mod a battery spring was with an LED flashlight build if the battery had a protection circuit, then I had to shorten the spring or replace the spring with a stronger shorter spring for better contact to get full looser to the LED driver. I’ll take a second look and see if the springs bent back or if they stayed after I adjudged them and let out know.
Title: Re: EEVBlog 121GW Discussion thread
Post by: IanB on May 22, 2018, 06:45:48 am
If anyone in the US can post a photo of the packaging then we'd be curious to see it. Thanks.

See pictures below. Essentially product box placed loose in shipping box with a tiny bit of bubble wrap for padding. Really no different from how Amazon packs stuff.

Title: Re: EEVBlog 121GW Discussion thread
Post by: Average Meatsack on May 22, 2018, 01:18:03 pm
Just got the notice that I have 48 hours to confirm the delivery address. Does that mean I am in the batch to receive my meter next? I just want to check as I am on a fixed term contract for the next 6 weeks and I would rather have my meter delivered to work since my house if unattended during the day and I want to ensure I get my delivery.

And if I as in the batch to get my meter next, Hell yeah!  :-+ :-DMM :clap: 
Title: Re: EEVBlog 121GW Discussion thread
Post by: dcac on May 22, 2018, 02:10:05 pm
Dave,

I elected to pre-pay the EU VAT but I've still not received any PayPal invoice for it, I've also sent you a message on Kickstarter about this some days ago...



Title: Re: EEVBlog 121GW Discussion thread
Post by: SmudgerD on May 22, 2018, 04:51:12 pm
Dave,

I elected to pre-pay the EU VAT but I've still not received any PayPal invoice for it, I've also sent you a message on Kickstarter about this some days ago...


Me too. I just got the last chance to confirm shipping address from Kickstarter, but have not received a PayPal invoice for the VAT. I do not want to be scalped by the courier for processing fees. Dave, please confirm that the PayPal thing is in hand.
Title: Re: EEVBlog 121GW Discussion thread
Post by: simon_staal on May 22, 2018, 05:28:30 pm
Hi

I am backer #2,228, and I backed for 2 meters. As I had to pay the VAT (european recidence) I was only charged for 1 meter. I left a comment on KS and payed anyway, hoping to still receive 2 meters. However, in the latest email regarding confirmation of the shipping address, it got confirmed that ONE meter is included in the shipment.

Is this due to an error, or is the second meter shipped from the next batch of meters? (Could be done this way to ensure all backers got at least 1 meter as soon as possible.)

Cheers!
Title: Re: EEVBlog 121GW Discussion thread
Post by: atcurtis on May 22, 2018, 06:53:29 pm
Backer #47 .. Received the meter today, #381.

It's going to take a while for me to get used to it since my older meters are a lot more primitive. I shall admit that my most-used meter was not auto-ranging.

Since there has been firmware updates, is the manual at http://www.eevblog.com/files/EEVblog-121GW-Manual.pdf (http://www.eevblog.com/files/EEVblog-121GW-Manual.pdf) the most current version of the manual? Mine did not arrive with any manual, only a calibration cert.
Title: Re: EEVBlog 121GW Discussion thread
Post by: firstcolle on May 22, 2018, 08:12:49 pm
looking forward to receiving mine, where can I buy reliable alligator clips for the supplied probes? (if they exists)
Title: Re: EEVBlog 121GW Discussion thread
Post by: Scottjd on May 22, 2018, 08:26:38 pm
Backer #47 .. Received the meter today, #381.

It's going to take a while for me to get used to it since my older meters are a lot more primitive. I shall admit that my most-used meter was not auto-ranging.

Since there has been firmware updates, is the manual at http://www.eevblog.com/files/EEVblog-121GW-Manual.pdf (http://www.eevblog.com/files/EEVblog-121GW-Manual.pdf) the most current version of the manual? Mine did not arrive with any manual, only a calibration cert.
It should be the latest manual. The manual does have a revision date in it. If the date matches close to the date of the latest firmware you can asssum it is. I think it also has a change log as well with dates changed.
Most of the firmwares have been bug fixes, I think the only change was VA now only goes to 50V, but the original manual didn’t have much listed for VA. So if anything they added the clause of the VA max now.

Enjoy using an auto ranging meter now,
Scott
Title: Re: EEVBlog 121GW Discussion thread
Post by: Candid on May 23, 2018, 01:07:48 am
looking forward to receiving mine, where can I buy reliable alligator clips for the supplied probes? (if they exists)
Franky has these and some more parts including the leads itself from Brymen:
Alligator Clips for 2mm Brymen tips:
https://www.ebay.de/itm/Brymen-Slip-on-Crocodile-Alligator-Clips-for-2mm-Probe-Tip-Gold-Spring-Contacts/171302315753?hash=item27e269e6e9:g:jFUAAOxyeZNTTkUm (https://www.ebay.de/itm/Brymen-Slip-on-Crocodile-Alligator-Clips-for-2mm-Probe-Tip-Gold-Spring-Contacts/171302315753?hash=item27e269e6e9:g:jFUAAOxyeZNTTkUm)

Simpler ones:
https://www.ebay.de/itm/Crocodile-Alligator-Clips-for-2mm-Probe-Tips-1-Pair-Red-and-Black/171224820971?hash=item27ddcb6ceb:g:HyQAAMXQQUpRDlze (https://www.ebay.de/itm/Crocodile-Alligator-Clips-for-2mm-Probe-Tips-1-Pair-Red-and-Black/171224820971?hash=item27ddcb6ceb:g:HyQAAMXQQUpRDlze)

Gold plated 4mm tip attachments:
https://www.ebay.de/itm/Gold-Plated-Lantern-Spring-Probe-Tip-Attachment-for-Brymen-Multimeter-Test-Leads/171243956885?hash=item27deef6a95:g:3FcAAMXQC-tTADeq (https://www.ebay.de/itm/Gold-Plated-Lantern-Spring-Probe-Tip-Attachment-for-Brymen-Multimeter-Test-Leads/171243956885?hash=item27deef6a95:g:3FcAAMXQC-tTADeq)

Or alligator clips for 4mm banana:
https://www.ebay.de/itm/56mm-Crocodile-Alligator-Clips-for-Shrouded-Banana-Plugs-1-Pair-Red-Black/171220194350?hash=item27dd84d42e:g:jhQAAOxyQj9RJX6s (https://www.ebay.de/itm/56mm-Crocodile-Alligator-Clips-for-Shrouded-Banana-Plugs-1-Pair-Red-Black/171220194350?hash=item27dd84d42e:g:jhQAAOxyQj9RJX6s)

or this:
https://www.ebay.de/itm/Dolphin-Alligator-Clips-for-4mm-Shrouded-Unshrouded-Plugs-1-Pair-Red-and-Black/202276233803?hash=item2f189a624b:g:mP4AAOSwlJlav4PM (https://www.ebay.de/itm/Dolphin-Alligator-Clips-for-4mm-Shrouded-Unshrouded-Plugs-1-Pair-Red-and-Black/202276233803?hash=item2f189a624b:g:mP4AAOSwlJlav4PM)

Mini grabber hooks for 2mm:
https://www.ebay.de/itm/20cm-Silicone-Leads-with-2mm-Gold-Plated-Sockets-and-Mini-Grabber-Hooks-Pair/171085144334?hash=item27d578210e:g:UMsAAOxyD9JR8h0p (https://www.ebay.de/itm/20cm-Silicone-Leads-with-2mm-Gold-Plated-Sockets-and-Mini-Grabber-Hooks-Pair/171085144334?hash=item27d578210e:g:UMsAAOxyD9JR8h0p)

The Brymen leads:
https://www.ebay.de/itm/Brymen-Silicone-Gold-Plated-Test-Leads-Probes-for-Multimeters-CAT-IV-1000V/171162377470?hash=item27da129cfe:g:uSQAAOxyTjNShpch (https://www.ebay.de/itm/Brymen-Silicone-Gold-Plated-Test-Leads-Probes-for-Multimeters-CAT-IV-1000V/171162377470?hash=item27da129cfe:g:uSQAAOxyTjNShpch)

And more... just have a look at his eBay account.
Title: Re: EEVBlog 121GW Discussion thread
Post by: tcottle on May 23, 2018, 02:57:33 am
And delivered.  It's Christmas in May!!!

Dave - thanks for all of your hard work bringing this meter to market.  It was a bit of a breech birth   ;D
Title: Re: EEVBlog 121GW Discussion thread
Post by: ez24 on May 23, 2018, 04:01:43 am
https://www.ebay.de/itm/Brymen-Slip-on-Crocodile-Alligator-Clips-for-2mm-Probe-Tip-Gold-Spring-Contacts/171302315753?hash=item27e269e6e9:g:jFUAAOxyeZNTTkUm (https://www.ebay.de/itm/Brymen-Slip-on-Crocodile-Alligator-Clips-for-2mm-Probe-Tip-Gold-Spring-Contacts/171302315753?hash=item27e269e6e9:g:jFUAAOxyeZNTTkUm)


or for US ebay:

https://www.ebay.de/itm/Brymen-Silicone-Gold-Plated-Test-Leads-Probes-for-Multimeters-CAT-IV-1000V/171162377470?hash=item27da129cfe:g:uSQAAOxyTjNShpch (https://www.ebay.de/itm/Brymen-Silicone-Gold-Plated-Test-Leads-Probes-for-Multimeters-CAT-IV-1000V/171162377470?hash=item27da129cfe:g:uSQAAOxyTjNShpch)

Is seller f-t-2000  a forum member ?   If so did he (he is in a Dave video) say he was moving to Australia and closing?  Sorry for my confusion.  I want to put a link to him in my List C because he is a respected seller that many members refer to.  (but I always forget thus the list) ?

thanks

Title: Re: EEVBlog 121GW Discussion thread
Post by: gnavigator1007 on May 23, 2018, 04:27:33 am
https://www.ebay.de/itm/Brymen-Slip-on-Crocodile-Alligator-Clips-for-2mm-Probe-Tip-Gold-Spring-Contacts/171302315753?hash=item27e269e6e9:g:jFUAAOxyeZNTTkUm (https://www.ebay.de/itm/Brymen-Slip-on-Crocodile-Alligator-Clips-for-2mm-Probe-Tip-Gold-Spring-Contacts/171302315753?hash=item27e269e6e9:g:jFUAAOxyeZNTTkUm)


or for US ebay:

https://www.ebay.de/itm/Brymen-Silicone-Gold-Plated-Test-Leads-Probes-for-Multimeters-CAT-IV-1000V/171162377470?hash=item27da129cfe:g:uSQAAOxyTjNShpch (https://www.ebay.de/itm/Brymen-Silicone-Gold-Plated-Test-Leads-Probes-for-Multimeters-CAT-IV-1000V/171162377470?hash=item27da129cfe:g:uSQAAOxyTjNShpch)

Is seller f-t-2000  a forum member ?   If so did he (he is in a Dave video) say he was moving to Australia and closing?  Sorry for my confusion.  I want to put a link to him in my List C because he is a respected seller that many members refer to.  (but I always forget thus the list) ?

thanks
Yes. I believe his brother in law or someone was taking over most of the ebay business.

https://www.eevblog.com/forum/profile/?u=26834 (https://www.eevblog.com/forum/profile/?u=26834)

His sales thread:
https://www.eevblog.com/forum/buysellwanted/franky_s-sales-thread/ (https://www.eevblog.com/forum/buysellwanted/franky_s-sales-thread/)
Title: Re: EEVBlog 121GW Discussion thread
Post by: Scottjd on May 23, 2018, 04:57:41 am
https://www.ebay.de/itm/Brymen-Slip-on-Crocodile-Alligator-Clips-for-2mm-Probe-Tip-Gold-Spring-Contacts/171302315753?hash=item27e269e6e9:g:jFUAAOxyeZNTTkUm (https://www.ebay.de/itm/Brymen-Slip-on-Crocodile-Alligator-Clips-for-2mm-Probe-Tip-Gold-Spring-Contacts/171302315753?hash=item27e269e6e9:g:jFUAAOxyeZNTTkUm)


or for US ebay:

https://www.ebay.de/itm/Brymen-Silicone-Gold-Plated-Test-Leads-Probes-for-Multimeters-CAT-IV-1000V/171162377470?hash=item27da129cfe:g:uSQAAOxyTjNShpch (https://www.ebay.de/itm/Brymen-Silicone-Gold-Plated-Test-Leads-Probes-for-Multimeters-CAT-IV-1000V/171162377470?hash=item27da129cfe:g:uSQAAOxyTjNShpch)

Is seller f-t-2000  a forum member ?   If so did he (he is in a Dave video) say he was moving to Australia and closing?  Sorry for my confusion.  I want to put a link to him in my List C because he is a respected seller that many members refer to.  (but I always forget thus the list) ?

thanks
Yes. I believe his brother in law or someone was taking over most of the ebay business.

https://www.eevblog.com/forum/profile/?u=26834 (https://www.eevblog.com/forum/profile/?u=26834)

His sales thread:
https://www.eevblog.com/forum/buysellwanted/franky_s-sales-thread/ (https://www.eevblog.com/forum/buysellwanted/franky_s-sales-thread/)
Confirmed. His brother-in-law did take over the store, Franky and his family did move to Australia.
I’ve still ordered from the shop a few times since he moved and the quality of the products have stayed the same, most of the inventory stayed the same. Even recent items that I ordered in the past were the same things. The shipping my times and packing is just as good as when Frankie ran the store.
And he replies to messages in the Frankie sales thread on the forum for good support. I just don’t bother to correct people, since it’s the same it’s easier to let them think it’s stjll Frankie since the store name and sales thread title didn’t change.
No worries, still the same great service and quality products. I would definitely put him on the list.
Scott
Title: Re: EEVBlog 121GW Discussion thread
Post by: Scottjd on May 24, 2018, 07:27:08 am
Here is a follow up on my initial thoughts. The way the switch was feeling bothered me, so I decided to take a look and found something unexpected. Now when I look at Dave’s video on 10K switch cycles it shows the shim with the routed area facing down over the C-Clip (or called e-clip in the instructions).
But if you look at the instructions is states the routed part must face “UPWARD” - see attached picture.

So my question comes with this “upward” statement, is this talking about upward meaning up as “facing up to the front of the meter towards the buttons? Or up as in up towards the ceiling or the sky so it will be facing the PCB when put back together?
Seems to me the routed area should go over the clip as shown in Dave’s switch testing video? The contact rotor disc that the shim meets with attached to the board doesn’t have anything sticking up that this routed out area on the shim would benefit from. Maybe it’s just how I’m interrupting the instructions, but if it’s supposed to go over the clip and the meter is taken apart facing front down on the table then it seems to make more sense the instructions say the router area needs to point downward, not upwards. Or just say it needs to go over the clip since the clip is mentioned and clearly pointed out in the instructions?

Does anyone have any clearifcation in this?
Thanks,
Scott
Title: Re: EEVBlog 121GW Discussion thread
Post by: ChunkyPastaSauce on May 24, 2018, 08:16:22 am
Fairly sure the recess is to give room for the raised shaft bore on the contact plate, so so spacer recessed face should face PCB when assembled (away from circlip).

(https://i.imgur.com/SDNuvbJ.png?1)

borrowed base image from BiOzZ https://imgur.com/a/vHISAb5
Title: Re: EEVBlog 121GW Discussion thread
Post by: Scottjd on May 24, 2018, 10:12:58 am
Fairly sure the recess is to give room for the raised shaft bore on the contact plate, so so spacer recessed face should face PCB when assembled (away from circlip).

(https://i.imgur.com/SDNuvbJ.png?1)

borrowed base image from BiOzZ https://imgur.com/a/vHISAb5
I think you may be correct. Mine did still work better, but I also dremeled off those three breakaway mold points as well and just didn’t put this in the video. Dave’s test video does show it backwards, and I saw that video before I realized instruction were available for those who had the switch sent to them.
I removed the video, updated it. And will lit the updated version up later. It still showed an issue with the 50M ohm range being affected by temperature. I’ve done some more testing since that video and confirmed this, just waiting for someone else to confirm this as well. I posted it in the bug reporting thread.
Thanks,
Scott
Title: Re: EEVBlog 121GW Discussion thread
Post by: chicken on May 25, 2018, 03:00:42 pm
Are there any release notes for the firmware updates?

I finally received my 121GW, and I wonder whether the update from 1.15 to 1.17 is worth the hassle.
Title: Re: EEVBlog 121GW Discussion thread
Post by: ChunkyPastaSauce on May 25, 2018, 03:10:29 pm
Are there any release notes for the firmware updates?

https://www.eevblog.com/forum/testgear/eevblog-121gw-multimeter-firmware-details/msg1563451/#msg1563451 (https://www.eevblog.com/forum/testgear/eevblog-121gw-multimeter-firmware-details/msg1563451/#msg1563451)
Title: Re: EEVBlog 121GW Discussion thread
Post by: vk2amv on May 26, 2018, 11:38:03 pm
Backer #525 here
I received meter #527

Two numbers off haha.
Meh close enough.

The meter actually turned up Monday last week, but only this weekend getting a chance to have a play due to work.

So far it is looking nice, and should go very nicely on my bench next to my Bryman BM235.

My first ever Kickstarter thing I have ever backed, and I only did so because I trusted Dave to deliver.
I can report that I am one very happy backer here and my faith was well placed.
Title: Re: EEVBlog 121GW Discussion thread
Post by: ChrisG on May 27, 2018, 12:07:34 am
Indeed you're right. The E or C-clip needs to go first over the knob and then the shim over the shaft. I tried to get the C (E) clip over the shaft on top of the shim and this was not possible and nearly broke the C (E) clip. I apologize if I'm complaining too much but my meter is mechanically not super well before and certainly after the shim installation. Too tight to turn the selector knob. I did notice just now one small incorrect statement in the manual (v17) on the buzzer on/off set-up option. It reads on page 59 " 4. Hold SETUP until a beep is heard to save the value. "  this is not true when saving for buzzer off setting.
Title: Re: EEVBlog 121GW Discussion thread
Post by: nidlaX on May 27, 2018, 08:16:49 am
Are the meters supposed to come with a pre-installed microSD card?
Title: Re: EEVBlog 121GW Discussion thread
Post by: ChunkyPastaSauce on May 27, 2018, 09:06:44 am
Are the meters supposed to come with a pre-installed microSD card?
Yes. Sandisk edge 8gb in mine, but don't know if all the same.
Title: Re: EEVBlog 121GW Discussion thread
Post by: ChunkyPastaSauce on May 27, 2018, 09:11:20 am
I apologize if I'm complaining too much but my meter is mechanically not super well before and certainly after the shim installation. Too tight to turn the selector knob.
Double check which way the shim is facing. Mine came with the shim flipped the wrong way, the knob was way too tight as a result. The recessed face of the shim should face the PCB when assembled (away from retaining ring on the shaft).
Title: Re: EEVBlog 121GW Discussion thread
Post by: Scottjd on May 27, 2018, 09:34:02 am
Are the meters supposed to come with a pre-installed microSD card?
Yes. Sandisk edge 8gb in mine, but don't know if all the same.
So far they have all been 8GB sandisk cards from what others have said.
Title: Re: EEVBlog 121GW Discussion thread
Post by: IanB on May 27, 2018, 12:07:09 pm
I found that when I took my meter apart the range selection knob had a smooth clicky feel to it, but when assembled with the shim it had a rough, grindy feel that I didn't like.

I observed that my meter had the same raised molding artifacts that Scottjd pointed out. So I did two things: I smoothed down the raised projections using fine sandpaper, and I applied a small amount of white lithium grease on the contact surface where the shim rubs against the meter back. Upon reassembly my range selection knob now has a smooth, silky and clicky action that it didn't have before.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Scottjd on May 27, 2018, 12:21:46 pm
I found that when I took my meter apart the range selection knob had a smooth clicky feel to it, but when assembled with the shim it had a rough, grindy feel that I didn't like.

I observed that my meter had the same raised molding artifacts that Scottjd pointed out. So I did two things: I smoothed down the raised projections using fine sandpaper, and I applied a small amount of white lithium grease on the contact surface where the shim rubs against the meter back. Upon reassembly my range selection knob now has a smooth, silky and clicky action that it didn't have before.
That’s great. I did the same thing. But I used a fine grit polishing dremel bit instead of sand paper. So far so good. I didn’t do any grease yet because I want to see if any dust is created or rubbing is still happening. I feared the grease would collect the dust from any other rubbing parts and it would make it hard to find the rubbing parts. And the grease may thicken if it had dust collected in it.  I’ll probably do anther tear down for a quick inspection in a month. But even without the grease it feel like most meters, if not better then some of the meters I own.
Keep us uodated on your meter and if you have any switch issues. So far mine is good, I don’t see removing those posts causing any issues. If you watch Dave’s switch testing video half of the circle posts wore down from the shim anyway and was probably the cause if the dust. And his shim had a small burr on it from the mounting wholes drilled in it, but my shim was smooth so I probably won’t see that.
I figure removing them just speed up the break in process without creating any dust.
Glad yours is working good now.
Scott
Title: Re: EEVBlog 121GW Discussion thread
Post by: Candid on May 27, 2018, 09:47:56 pm
Yes, 4GB when I remember correctly.
Title: Re: EEVBlog 121GW Discussion thread
Post by: ANTALIFE on May 27, 2018, 11:00:21 pm
For those with a 3D printer, I made a wall-mount holder which you can get here:
https://www.thingiverse.com/thing:2932921 (https://www.thingiverse.com/thing:2932921)
Title: Re: EEVBlog 121GW Discussion thread
Post by: IanB on May 28, 2018, 03:16:26 am
Can someone do a test on their 121GW to see if it's the same as mine?

1. Put the meter in resistance mode
2. Manually set the range to 0.000 Ω
3. Short the probes (use alligator clips so you don't have to hold them)
4. Expect to see a fluctuating reading in the 0.03 to 0.05 range depending on the probe resistance
5. Press the min/max button to capture the max reading
6. Now lightly touch the HOLD button with your finger and pull it away again (don't press it, just touch it gently)

What does the display capture?

On my meter the reading jumps up dramatically as high as 0.2, 0.3 or even 0.5 Ω

Something similar happens if I press the REL button to null out the probe resistance. Pressing the REL button makes the reading jump high, making it impossible to null out the probe resistance in this range.

Also, occasionally step 4 will show an anomalous reading, for example yesterday the meter showed about 3 ohms. It persistently showed 3 ohms even after turning the meter off and on again and after sweeping the dial through all the other ranges. The shorted probe resistance reading only went back to normal after I put the meter in DC volts and measured a battery. Then suddenly I got the expected 0.035 ohm probe resistance. I have not figured out what event causes the meter to get into this state.
Title: Re: EEVBlog 121GW Discussion thread
Post by: ChunkyPastaSauce on May 28, 2018, 03:51:23 am
Can someone do a test on their 121GW to see if it's the same as mine?

1. Put the meter in resistance mode
2. Manually set the range to 0.000 Ω
3. Short the probes (use alligator clips so you don't have to hold them)
4. Expect to see a fluctuating reading in the 0.03 to 0.05 range depending on the probe resistance
5. Press the min/max button to capture the max reading
6. Now lightly touch the HOLD button with your finger and pull it away again (don't press it, just touch it gently)

What does the display capture?

On my meter the reading jumps up dramatically as high as 0.2, 0.3 or even 0.5 Ω

Something similar happens if I press the REL button to null out the probe resistance. Pressing the REL button makes the reading jump high, making it impossible to null out the probe resistance in this range.

Yes I'm having this, meter goes way out of spec, 0.5 \$\Omega\$ or more, v1.17. It happens whether max mode is on or not. I also see it in dc mv range (especially 500mv) and the temp thermocouple mode. On mine range, hold, rel, and min/max buttons will do it.I pulled apart the meter to see if anything under the button membranes, but didnt see anything weird. Right now the REL and min/max functions often not usable in mv,ohm,temp modes. https://www.eevblog.com/forum/testgear/eevblog-121gw-multimeter-issues/msg1561363/#msg1561363 (https://www.eevblog.com/forum/testgear/eevblog-121gw-multimeter-issues/msg1561363/#msg1561363)

Since you're checking hardware related things, could you check the 1kHz LPF? My unit seems to be way too low below 1kHz (starts to atten around 30hz). https://www.eevblog.com/forum/testgear/eevblog-121gw-multimeter-issues/msg1563436/#msg1563436 (https://www.eevblog.com/forum/testgear/eevblog-121gw-multimeter-issues/msg1563436/#msg1563436)

Also, occasionally step 4 will show an anomalous reading, for example yesterday the meter showed about 3 ohms. It persistently showed 3 ohms even after turning the meter off and on again and after sweeping the dial through all the other ranges. The shorted probe resistance reading only went back to normal after I put the meter in DC volts and measured a battery. Then suddenly I got the expected 0.035 ohm probe resistance. I have not figured out what event causes the meter to get into this state.
I don't think I've seen this one

Title: Re: EEVBlog 121GW Discussion thread
Post by: IanB on May 28, 2018, 04:06:22 am
Yes I'm having this, meter goes way out of spec, 0.5 Ω or more, v1.17. It happens whether max mode is on or not.

Yes, the display jumps regardless. Pressing the MIN/MAX button just makes it easier to capture the reading.
Title: Re: EEVBlog 121GW Discussion thread
Post by: IanB on May 28, 2018, 07:37:04 am
How to make the meter show weird readings:

1. Put the meter on the Low Z range
2. Measure the mains voltage (let's say 120.0 V AC)
3. Put the meter on the Resistance range
4. Short the probes

You may observe an anomalous reading of about 3 ohms, slowly declining towards zero.

On other ranges (like DC mV) you may observe anomalous readings too.

It's as if a capacitor is charged up and is taking time to discharge back to zero volts. (Or did something heat up and it's taking time to cool down?)
Title: Re: EEVBlog 121GW Discussion thread
Post by: nidlaX on May 28, 2018, 07:42:25 am