Author Topic: EEVBlog 121GW Discussion thread  (Read 233155 times)

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Offline exe

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Re: EEVBlog 121GW Discussion thread
« Reply #1575 on: June 11, 2019, 11:30:36 am »
Afaik all DMMs are "differential" in a sense they are not referenced to ground.

As of measuring larger current, just use an external shunt.
 

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Re: EEVBlog 121GW Discussion thread
« Reply #1576 on: June 11, 2019, 12:38:15 pm »
So the TV options sucked tonight. On the printer but I am off to bed at 10.30pm so we will see what the morning brings. I may have made the press section to strong to push in so it might take a tweak yet.

Printed heavy and on it's side with supports to get the layer orientation correct for strength. If it looks ok I will swing 4 or 5kg extra on mine to test before releasing the final design. Add your own magnet, webbing or a lump of old rope....



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Re: EEVBlog 121GW Discussion thread
« Reply #1577 on: June 12, 2019, 01:50:40 am »
Overall size is nicely snug so the tongue will be gripped by the bumper on all sides. The Push release with PLA isn't and is to stiff. Printed in PETG would be more flexible and tougher but I am aiming for a PLA printable with 0.2mm layers so all 3D printers can manage it. Also need to reduce the release length and round it's corners to suit the bumper. It fits in the zip up case installed so even if the release is hard to use not that much of an issue I guess and it can just stay locked in.

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Online beanflying

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Re: EEVBlog 121GW Discussion thread
« Reply #1578 on: June 12, 2019, 05:10:33 am »
Tweakage finished unless anyone who makes it finds an issue and I will see if it can be improved.

Hollowed out the release so it now has more flex, fattened up the front bar for more strength and short of hanging your toolbag on it shouldn't ever be a problem. Also increased the web at the rear of the release for more strength when being pressed. The release as it is here in PLA can be deflected down by about 3mm without any risk of breaking it and the urethane section of the bumper can easily be flipped over it then to release the hanger. Still recommend PETG if you have it (I will try one next time I have some loaded).

Print settings 6 layers all round 40% infill so basically solid at 0.2mm layers. Printed on edge with bed supports only, could fully support it but the one shown in this post wasn't. STL is in the Zip file attached here.
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Re: EEVBlog 121GW Discussion thread
« Reply #1579 on: June 12, 2019, 06:26:40 am »
It fits UEI's magnetic hanger, but I don't actually sell that.

This one, I assume:
https://www.ueitest.com/products/accessories/amh1

Yep, I think that's the one.
Could probably make a little slide in adapter that took some sort of standard size magnet (say 10mm dia) and allowed it to fit snug inside.
 
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Re: EEVBlog 121GW Discussion thread
« Reply #1580 on: June 12, 2019, 07:18:39 am »
It fits UEI's magnetic hanger, but I don't actually sell that.

This one, I assume:
https://www.ueitest.com/products/accessories/amh1

Yep, I think that's the one.
Could probably make a little slide in adapter that took some sort of standard size magnet (say 10mm dia) and allowed it to fit snug inside.

Very rough 5 minute hack up to take a 20x10mm 5mm c/sunk magnet. It needs to be this tall to clear the rubber bumper.
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Online beanflying

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Re: EEVBlog 121GW Discussion thread
« Reply #1581 on: June 12, 2019, 08:17:47 am »
And here is a nicer one.

Designed to take a 20x10 5mm Magnet (Order away I have already  ;) ) eBay auction: #183364882157
Countersunk 5mm screw or bolt to suit and the recess will take a Nyloc nut for depth but a standard one and lock washer would do too.

I haven't printed this one but using the settings above should print fine. STL is in the Zip.

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Offline e0ne199

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Re: EEVBlog 121GW Discussion thread
« Reply #1582 on: June 12, 2019, 12:50:59 pm »
hello i have a question...
does 121GW multimeter have differential probe for measuring current? i want to measure current around more than 10 Amps on my device anyway
answer is really appreciated, thx before

A differential probe for... current? What is your use case?

Without more information or your requirements (AC or DC? Contactless or resistive current measurement? Are the sources isolated?), the following methods may work.

Multiple 121GW meters can connect to an Android device or Windows PC via Bluetooth, and math functions can be performed against the connected meters. You could simply take the subtraction of the readings between two connected meters.

Resistive:
  • 2x 121GW meters (or any oscilloscope with simple math functions + some milliohm-scale power resistors)
  • An Android device or Windows PC (if using the 121GW)
Contactless:
  • 2x 121GW meters (or any oscilloscope with simple math functions)
  • 2x hall-effect current sensors, such as the PDI CA-60
  • An Android device or Windows PC (if using the 121GW)

It may be more cost-effective (and offer greater insight) to use a cheap oscilloscope such as a Rigol DS1054Z than multiple 121GW meters. Depending on your requirements, you could also build a circuit to do this, and measure it with a single 121GW (or any other meter or oscilloscope).

But answer the specifically asked question: no, the 121GW doesn't have any differential probes.

haha i asked a wrong question i think...i mean external current probe clamp for 121GW that can measure current more than 10 amps, i am sorry i thought when i mentioned differential probe that would mean external current probe clamp  ;D

maybe i need to repeat the question again..does 121GW have external current probe clamp for measuring high current (more than 10 amps)?
 

Offline lowimpedance

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Re: EEVBlog 121GW Discussion thread
« Reply #1583 on: June 17, 2019, 06:22:18 am »
Tweakage finished unless anyone who makes it finds an issue and I will see if it can be improved.

Hollowed out the release so it now has more flex, fattened up the front bar for more strength and short of hanging your toolbag on it shouldn't ever be a problem. Also increased the web at the rear of the release for more strength when being pressed. The release as it is here in PLA can be deflected down by about 3mm without any risk of breaking it and the urethane section of the bumper can easily be flipped over it then to release the hanger. Still recommend PETG if you have it (I will try one next time I have some loaded).

Print settings 6 layers all round 40% infill so basically solid at 0.2mm layers. Printed on edge with bed supports only, could fully support it but the one shown in this post wasn't. STL is in the Zip file attached here.

 I have printed your design using ABS, and it was completely successful with no issues so far. As printed the hanger snaps confidently into the slot on the bumper, (support material removed of course!).
The locking tab works perfectly and can be easily depressed for removal from the meter, no structural problems observed after many test operations.
See attached photos using a FLUKE hanger  :D.
 Thanks again for the effort.
The odd multimeter or 2 or 3 or 4...or........can't remember !.
 
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Offline frankmhowell

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Re: EEVBlog 121GW Discussion thread
« Reply #1584 on: July 04, 2019, 02:22:43 pm »
But what is the metric of the Time field? Is it in interval units (e.g., seconds, etc.) relative to the start time stamp? As successfully received via Bluetooth?
 

Offline Dr. Frank

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New version of manual online: EEVBlog 121GW Discussion thread
« Reply #1585 on: August 08, 2019, 01:41:30 pm »
Hello,

an updated version (8th of August 2019)  of the manual is online

Frank

Goto: https://www.eevblog.com/product/121gw/    => documentation

« Last Edit: August 08, 2019, 01:43:52 pm by Dr. Frank »
 
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Offline mattbrockuk

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Re: EEVBlog 121GW Discussion thread
« Reply #1586 on: August 16, 2019, 06:20:41 am »
Very slow on this i'm sure, but just clicked about this products model number lol... back to the future rules!   :D
 

Offline jchw4

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Re: New version of manual online: EEVBlog 121GW Discussion thread
« Reply #1587 on: August 19, 2019, 03:08:13 am »
Hello,

an updated version (8th of August 2019)  of the manual is online

Frank

Goto: https://www.eevblog.com/product/121gw/    => documentation

The difference is pretty minimal: https://www.diffchecker.com/bQNsVKdS

Added to the document changelog:
Quote
08/08/2019
Added battery voltage check to the firmware update pro-
cedure.

Added v2.00 firmware version changelog:
Quote
2.00
Improved the Auto-ranging reading speed in both ca-
pacitance and resistance ranges.

Added requirement to check battery voltage prior to updating firmware:
Quote
1. Ensure the low battery indicator is not present.
See Battery Voltage, Page 60.

It all looks to be a response to https://www.eevblog.com/forum/testgear/eevblog-121gw-multimeter-issues/msg2570484/#msg2570484 .
 

Offline Bobo666

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Re: EEVBlog 121GW Discussion thread
« Reply #1588 on: September 12, 2019, 02:13:28 am »
Looking at purchasing this. Mainly interested in the logging feature.

Have most of the known bugs been taken care of?

Do all the new meters come with the upgraded dial?

Anyone using it for logging (either BLE or card) and how do you find it?

Thanks
 

Offline dr.diesel

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Re: EEVBlog 121GW Discussion thread
« Reply #1589 on: September 12, 2019, 10:24:29 am »
Looking at purchasing this. Mainly interested in the logging feature.

BLE logging is still very broken.

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Re: EEVBlog 121GW Discussion thread
« Reply #1590 on: September 12, 2019, 11:07:11 am »
Looking at purchasing this. Mainly interested in the logging feature.

BLE logging is still very broken.
And you still have that signature ?  :-//
Avid Rabid Hobbyist
 

Offline Bobo666

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Re: EEVBlog 121GW Discussion thread
« Reply #1591 on: September 13, 2019, 03:21:50 am »
Looking at purchasing this. Mainly interested in the logging feature.

BLE logging is still very broken.

That is unfortunate, especially after so many firmware updates.
 

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Re: EEVBlog 121GW Discussion thread
« Reply #1592 on: September 13, 2019, 04:14:32 am »
Broken isn't the right term but buggy is closer with the bluetooth. It has improved over the release version but would still benefit from more work on the app.

I am still running V1.58 firmware as I haven't got around to an upgrade yet. Pulled it out of my site bag, turned it on hooked straight up to my Galaxy 7 and starting logging the mains in the shack. This data in the spread sheets below is off the App to the phone then emailed off the app.

I hadn't installed thew windoze app on my new box so I did that and it hooked up too. Screen caps below. So not broken :-//

The hits to voltage are from my 3500W espresso machine kicking in and out. The logging data isn't where it should be as the 'precise timing' from the meter is bs and still needs fixing to something meaningful or sensible preferably at the meter end in firmware.
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Offline CDaniel

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Re: EEVBlog 121GW Discussion thread
« Reply #1593 on: September 13, 2019, 06:44:03 am »
OK , is somewhat working , not completely dead  ;) , but if is not reliable as many have said , sometimes recording false values , no time stamps , and so on , I would say it's like a broken toy  . Or simply a toy for beginers in electronics , just to see something on the screen .
This is not to be espected from a quality brand multimeter .
 

Online beanflying

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Re: EEVBlog 121GW Discussion thread
« Reply #1594 on: September 13, 2019, 06:46:16 am »
And continuing to be an ASSHAT and adding zero to the discussion again  :palm:
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Offline Bobo666

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Re: EEVBlog 121GW Discussion thread
« Reply #1595 on: September 13, 2019, 09:57:34 am »
Broken isn't the right term but buggy is closer with the bluetooth. It has improved over the release version but would still benefit from more work on the app.

The logging data isn't where it should be as the 'precise timing' from the meter is bs and still needs fixing to something meaningful or sensible preferably at the meter end in firmware.

Thank you for the pics and data. I'm not so much interested in the apps as I intended to stream the data straight to Node Red (perhaps others have already done the same?), but your second comment doesn't inspire with confidence achieving this as the data needs to be fairly precise coming from the meter itself.

Need to give it some more thought. Thanks again. And also thanks for the additional "banter"  ;)
 

Online beanflying

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Re: EEVBlog 121GW Discussion thread
« Reply #1596 on: September 15, 2019, 02:11:06 am »
Precision, Accuracy etc are a matter of reference. You need to specify it to have a frame of reference. My biggest beef with the software/meter for logging is the BS timebase used not the 'accuracy' of the meter. The timebase can be post edited in a spreadsheet with a little maths but it shouldn't have to be.

Against my recently calibrated Keysight 34461A snd I haven't looked at recalibrating it against this and my in cal 34401A but it is well within the combined error margin of both.

Rough setup and plenty of possibilities for stray noise to play with the BT but looking for dropped results and NOPE.

30 minutes of logging with a rough setup as shown and lets look at the 'false recordings' and other random unsubstantiated claims of the Troll boy in chief - NOPE :palm:



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Offline J-R

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Re: EEVBlog 121GW Discussion thread
« Reply #1597 on: September 15, 2019, 03:08:01 am »
I feel sorry for someone trying to research this meter for purchase. There is too much back and forth and these threads are ridiculous for trying to find the current status of the meter.  I suppose an official page with all the firmware versions and known and fixed "concerns" listed out would be too much to ask for???  There really should be one page that lists out everything a 121GW owner (or potential owner) needs to know.  For example, there are different hardware versions/updates, a recall of specific serial numbers, troubleshooting suggestions, etc....

How about a new pinned thread with strict rules on new posts?
 
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Online 2N3055

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Re: EEVBlog 121GW Discussion thread
« Reply #1598 on: September 15, 2019, 08:03:19 am »
Precision, Accuracy etc are a matter of reference. You need to specify it to have a frame of reference. My biggest beef with the software/meter for logging is the BS timebase used not the 'accuracy' of the meter. The timebase can be post edited in a spreadsheet with a little maths but it shouldn't have to be.

Against my recently calibrated Keysight 34461A snd I haven't looked at recalibrating it against this and my in cal 34401A but it is well within the combined error margin of both.

Rough setup and plenty of possibilities for stray noise to play with the BT but looking for dropped results and NOPE.

30 minutes of logging with a rough setup as shown and lets look at the 'false recordings' and other random unsubstantiated claims of the Troll boy in chief - NOPE :palm:

Thanks for the test. Real experiment and real data is only important thing.


If you're willing to make another one let me suggest parameters that would be more relevant to dispense with all of the fluff once and for all.

Logging time should be at least 24h. Use case would be leaving meter to monitor battery state, or monitor charge/discharge cycle.

I see you have very nice SDG 2000X. Any AWG should do, actually.
Siggen should be set to create low frequency sine wave. Something like 20 second cycle ( 50 mHz ). Make it nice 4.8 V P-P.
Set meter to DC, 5V range manual.
Make a logging to a SD card and BT.

For 24 hours. Why 24 hours? Because that is what logging is for. 30 minutes is not proof.
Those who reported problems said meter can sometimes log for hours at a time without problems.
Why sine wave? Because of its nature, it is easy to detect any discontinuities, missed points, nonlinearities...

Post original data file here.

Can anybody make this 2 tests? To experimentally prove one or the other.
If it's working OK, great news. If there are problems, it will be quality data for manufacturer to fix the problem.

Regards,
 

Offline Bobo666

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Re: EEVBlog 121GW Discussion thread
« Reply #1599 on: September 15, 2019, 09:50:35 am »
I feel sorry for someone trying to research this meter for purchase. There is too much back and forth and these threads are ridiculous for trying to find the current status of the meter.  I suppose an official page with all the firmware versions and known and fixed "concerns" listed out would be too much to ask for???

I have to say that I was a bit surprised at the official support for this meter when I came looking. Dave being Dave, I assumed that he would've been fairly thorough in providing this (official updates, notifications etc). There isn't even a readme file attached to the firmware zip.

Also I just discovered that there is hardware (pcb?) upgrade to fix (I assume) the rotary dial issue? Has this change been rolled out to for sale units?

Anyhow perhaps I'm being a bit too critical as I don't know the history behind the meter. 
 


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