Author Topic: EEVBlog 121GW Discussion thread  (Read 770555 times)

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Offline skyjumper

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Re: EEVBlog 121GW Discussion thread
« Reply #1125 on: October 02, 2018, 09:05:44 pm »
Thanks! I see they charge $23 euro (about) to ship to the US via some insured / tracked method. Does anyone else sell these?
 

Offline GeoffreyF

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Re: EEVBlog 121GW Discussion thread
« Reply #1126 on: October 02, 2018, 10:36:16 pm »
I have noted that the 121GW goes "in stock" in lots of 32 units.  These units are usually sold within a week.  Just keep checking every couple of days and keep that credit card handy.   Check on the site too because (if memory serves) they ship on Tuesday and Thursday (australia time).   I got my meter in the Boston, MA, USA  area about 5 days after shipping, which is pretty good.  This was a few weeks ago and so this is a fairly up-to-date description of the process. 
US Amateur Extra W1GCF.
 
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Offline skyjumper

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Re: EEVBlog 121GW Discussion thread
« Reply #1127 on: October 03, 2018, 04:52:45 am »
I have noted that the 121GW goes "in stock" in lots of 32 units.  These units are usually sold within a week.  Just keep checking every couple of days and keep that credit card handy.   Check on the site too because (if memory serves) they ship on Tuesday and Thursday (australia time).   I got my meter in the Boston, MA, USA  area about 5 days after shipping, which is pretty good.  This was a few weeks ago and so this is a fairly up-to-date description of the process.

Yippie, they are back in stock! Order placed, thank you! Dave could use a US based distributor though...
« Last Edit: October 03, 2018, 05:01:51 am by skyjumper »
 

Offline Yannik

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Re: EEVBlog 121GW Discussion thread
« Reply #1128 on: October 03, 2018, 04:34:03 pm »
Is it really impossible to have the backlight on by default? It's pretty annoying to turn it on by hand everytime you use the meter.
 

Offline TikhonovC

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Re: EEVBlog 121GW Discussion thread
« Reply #1129 on: October 03, 2018, 08:12:35 pm »
Yes,
I would like the multimeter to remember the last state of the backlight.
 

Offline Kim

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Re: EEVBlog 121GW Discussion thread
« Reply #1130 on: October 05, 2018, 02:39:17 pm »
While we're on the subject of the backlight, how about an option to light it up along with (or instead of) the beep in continuity test mode?  It's a small feature that would make a big difference to people with hearing loss, or just for when you're trying to troubleshoot a dicky connection without annoying everyone else in the room.

(Received my 121GW last week, really liking it so far.)
 

Offline Brumby

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Re: EEVBlog 121GW Discussion thread
« Reply #1131 on: October 06, 2018, 02:14:47 am »
That would be useful for people with hearing loss or just someone working in a very noisy environment.

Well, I don't have a 121GW yet, so I can't comment, but the BM235 flashes the backlight in continuity mode - and it does so whether the backlight is off or had been turned on.  (Yes, I have a BM235).

If the 121GW doesn't have this feature, I would like to see it implemented.  The option to switch off the beeper is one I would be guarded about.  That is a setting I would want to have automatically reset at switching off so the next time I turn the meter on, I don't interpret silence as a lack of continuity.
 

Offline GeoffreyF

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Re: EEVBlog 121GW Discussion thread
« Reply #1132 on: October 06, 2018, 10:40:48 pm »
I think that actually there should be an option for the beep to transmit the readout and state in morse code.   Blind people could then work with high voltages too.  Anyway, that's the kind of thing Brumby would want.
US Amateur Extra W1GCF.
 

Offline Brumby

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Re: EEVBlog 121GW Discussion thread
« Reply #1133 on: October 07, 2018, 02:33:21 am »
I'm not advocating such stupidity, so don't dump this crap on me - OK?  You are just being childish.  Or is this another case of "I'm not a member of the club, so my opinion is offensive"?

This is not something I've dreamed up.  It's already been implemented in other meters.  If you want to properly consider the use case for backlight being used with continuity, then check out the discussion on this exact point with the BM235.

« Last Edit: October 07, 2018, 02:36:19 am by Brumby »
 

Offline dcac

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Re: EEVBlog 121GW Discussion thread
« Reply #1134 on: October 07, 2018, 12:34:30 pm »
That would be useful for people with hearing loss or just someone working in a very noisy environment.

Well, I don't have a 121GW yet, so I can't comment, but the BM235 flashes the backlight in continuity mode - and it does so whether the backlight is off or had been turned on.  (Yes, I have a BM235).

If the 121GW doesn't have this feature, I would like to see it implemented.  The option to switch off the beeper is one I would be guarded about.  That is a setting I would want to have automatically reset at switching off so the next time I turn the meter on, I don't interpret silence as a lack of continuity.

You’re quite right it would be a useful feature and it would also be nice if it was made a configurable option in the setup. But UEi will probably be focusing on bugfixes for quite a while though - before implementing new features. But perhaps it is possible to hack/modify the firmware to achieve something like this.

 

Offline Visitor

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Re: EEVBlog 121GW Discussion thread
« Reply #1135 on: October 07, 2018, 05:22:32 pm »
Does anybody know if there will be an option to NOT store the last settings of the functions?
 

Offline Bratster

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Re: EEVBlog 121GW Discussion thread
« Reply #1136 on: October 07, 2018, 05:24:37 pm »
Does anybody know if there will be an option to NOT store the last settings of the functions?
That is sorely needed IMO.

Sent from my Fi Moto x4 using Tapatalk

 

Offline CDaniel

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Re: EEVBlog 121GW Discussion thread
« Reply #1137 on: October 07, 2018, 07:46:26 pm »
Many little features can be added , but there are some important ones not very good implemented .
For exemple capacitance measurement has low resolution , only 3 digits 1000 counts , so for 220nF you can't see anything extra . And very , very slow autoranging in comparison with other multimeters. HY3131 is capable for more performance
« Last Edit: October 08, 2018, 06:49:07 am by CDaniel »
 

Offline Visitor

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Re: EEVBlog 121GW Discussion thread
« Reply #1138 on: October 08, 2018, 07:18:35 am »
You are right.
The ultra slow autoaranging ist the second big mistake after the ugly battery holder.
Every 30$ China crap is at least 2 times faster.
 

Offline Seppy

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Re: EEVBlog 121GW Discussion thread
« Reply #1139 on: October 09, 2018, 12:07:58 am »
Nope, doesn't do ESR, you would need an LCR meter.
 

Offline CDaniel

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Re: EEVBlog 121GW Discussion thread
« Reply #1140 on: October 09, 2018, 06:36:24 pm »
We don't want ESR , but could we get in near future a rework of the capacitance measurement ?

1 . More resolution , 3digits 1000counts for lower ranges is too low , even the entry level meters in these days have 4000-6000 counts for capacitance . The chipset HY3131 is for sure more capable .
2 . Bargraph if possible
3 . Improved autorange speed
4 . I don't think the firmware has the feature "discharge capacitors" implemented . Anyway when you connect ( by mistake ) a charged capacitor the display should show "discharge" or something while performing this.

Maybe someone could add more to this list
« Last Edit: October 09, 2018, 08:09:22 pm by CDaniel »
 
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Offline EEVblog

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Re: EEVBlog 121GW Discussion thread
« Reply #1141 on: October 10, 2018, 02:15:10 am »
Many little features can be added , but there are some important ones not very good implemented .
For exemple capacitance measurement has low resolution , only 3 digits 1000 counts , so for 220nF you can't see anything extra . And very , very slow autoranging in comparison with other multimeters. HY3131 is capable for more performance

We'll add it to the list to be looked at.
 

Offline EEVblog

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Re: EEVBlog 121GW Discussion thread
« Reply #1142 on: October 10, 2018, 02:21:41 am »
The backcover om my 121gw is a very tight fit and would never fall off by it self - so I just don’t tighten the two screws at all if I’m doing any logging.

I don't understand the fuss over the SD card access. It is the way it is for compliance reasons.
If anyone is using the data logger function so often that the access is a problem then I suggest you get a real data logger with convenient data access and/or transfer.
The SD card was designed for firmware updates that could also be used as a data logger at a pinch if needed. You wouldn't buy this meter to replace a "data logger", that's not it's job.
 

Offline dcac

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Re: EEVBlog 121GW Discussion thread
« Reply #1143 on: October 10, 2018, 09:50:02 am »
Logging to a SD card is a very nice feature on the 121gw, and even if getting access to the card - does not take that much time - I can understand people leaving the backcover off completely if they know they soon going to pull that card anyway. And still with the backcover off - pulling and mounting the card in the holder is a bit fiddly so sooner or later you probably end up breaking the holder as there’s no guides or anything to protect it.

All this could be solved with a function to dump the log file over the Bluetooth interface, you’d think that shouldn’t be too hard to implement, I mean there’s already a function to view and step through the log on the meter.
 

Offline chronos42

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Re: EEVBlog 121GW Discussion thread
« Reply #1144 on: October 10, 2018, 04:00:41 pm »
Hi,

I agree, access to the SD card filesystem (readonly is sufficient) via bluetooth would solve all these discussions. That should be possible with this ARM processor that is build in the meter.
« Last Edit: October 10, 2018, 06:12:32 pm by chronos42 »
 

Offline chronos42

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Re: EEVBlog 121GW Discussion thread
« Reply #1145 on: October 10, 2018, 07:13:44 pm »
Hi,
This is indeed slow, but I assume the logging data transfer is synchronised with the ADC sampling and would be faster with a datatransfer from the SD card?
 

Offline Seppy

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Re: EEVBlog 121GW Discussion thread
« Reply #1146 on: October 15, 2018, 12:15:44 am »
Hi,
This is indeed slow, but I assume the logging data transfer is synchronised with the ADC sampling and would be faster with a datatransfer from the SD card?

Well, I'm not so sure.  They write to the SD card much faster than they send the data over BLE.  They have even slowed down the BLE transfers compared with the early firmware versions.  I assume they were trying to improve reliability by going from ASCII to binary, reducing the payload and then slowing it down  but I'm not sure.   The meter can certainly update faster than 2Hz so I don't believe it would speed up if they were doing a data transfer.   

Again, I am not suggesting it could not be done only that from what I see, it appears throttled like Barbie's Mustang and not Grind Hard Plumbing's version.   

https://www.youtube.com/channel/UCivi_f1nniBzEOfKhRoN12Q

Your speculation is accurate for the most part.
We might be able to improve BLE speed now that we have reduced the packet size. But, we have some outstanding issues that will take precedence so it could be a while before this change occurs (if its possible).
 

Offline nealz

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Re: EEVBlog 121GW Discussion thread
« Reply #1147 on: October 16, 2018, 02:16:27 am »
Does anyone know where I can get a magnetic hanger for the 121GW meter? I say some posts on the forum that mentioned compatible with Klein hangers but I found a few different styles/models.

If you know of a confirmed compatible hanger please let me know.

Thanks
Neal
 

Offline Seppy

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Re: EEVBlog 121GW Discussion thread
« Reply #1148 on: October 16, 2018, 06:21:49 am »
There is a fair bit of overhead sending that one byte packet.   :-DD

There were other motivating factors also which included differences in implementation for BLE on different platforms. Some platforms have a longer buffer than others and it needed to come in one packet.
The number of platforms this device supports was also a factor in the reduction of the packet size.
 

Offline FrankBuss

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Re: EEVBlog 121GW Discussion thread
« Reply #1149 on: October 16, 2018, 06:49:09 am »
The max payload for a GATT Characteristic, which can be sent in one physical BLE packet, is 20 bytes. Once I implemented the nRF UART protocol on a Silabs Blue Gecko, with a length of 20 for the TX and RX characteristics, and with a stress test I never lost a packet from the device to the PC (running a Python script with bluepy). So I assume it is good to have a packet size of 20 bytes or less, but wouldn't make sense to limit it to a smaller size. Each physical packet has a CRC checksum (additional bytes, not part of the payload) and a packet is either received fully or not received at all.

I guess there can be problems, if you set the length of a GATT Characteristic to more than 20 bytes, because then the underlying BLE implementation has to split it in multiple physical packets.
So Long, and Thanks for All the Fish
Electronics, hiking, retro-computing, electronic music etc.: https://www.youtube.com/c/FrankBussProgrammer
 
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