Author Topic: EEVBlog 121GW Discussion thread  (Read 214663 times)

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Offline chronos42

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Re: EEVBlog 121GW Discussion thread
« Reply #1400 on: February 21, 2019, 07:15:59 pm »
Thanks for showing the video from Kainka Labs and also joeqsmith for his suggestion how to connect the 121GW in VA mode to avoid the problem of wrong VA readings.

Just for fun I did the same test with the Gossen Metrahit Energy. Same setup as in the video, 1V source, resistor 22 Ohm. The Gossen is connected as it should, gnd to gnd, voltage input to the +1V output of the source and the current input is connected to the resistor, the resistor is connected to 1V source.

The result is shown at picture 1   :-+

Then I changed GND and current input at the Gossen. Result is picture 2.  8)

That means that the Gossen meter uses the same wiring in the power mode which joeqsmith suggested for the 121GW.
« Last Edit: February 21, 2019, 07:39:19 pm by chronos42 »
 
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Online IanB

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Re: EEVBlog 121GW Discussion thread
« Reply #1401 on: February 21, 2019, 07:40:55 pm »
I did some experiments on power measurement with the 121GW and I observed the "correct" way to connect it to measure power consumed by a load resulted in a negative display value for the power.

At first I didn't like this, but actually you could argue that power consumed is negative and power produced is positive. So perhaps it is just a matter of human perspective rather than any technical limitation of the system?
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Offline chronos42

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Re: EEVBlog 121GW Discussion thread
« Reply #1402 on: February 21, 2019, 08:13:46 pm »
Think in "drain" and "source". Source is positive, drain is negative and than it fits.... :)
 

Offline joeqsmith

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Re: EEVBlog 121GW Discussion thread
« Reply #1403 on: February 21, 2019, 10:11:38 pm »
Thanks for showing the video from Kainka Labs and also joeqsmith for his suggestion how to connect the 121GW in VA mode to avoid the problem of wrong VA readings.

Just for fun I did the same test with the Gossen Metrahit Energy. Same setup as in the video, 1V source, resistor 22 Ohm. The Gossen is connected as it should, gnd to gnd, voltage input to the +1V output of the source and the current input is connected to the resistor, the resistor is connected to 1V source.

The result is shown at picture 1   :-+

Then I changed GND and current input at the Gossen. Result is picture 2.  8)

That means that the Gossen meter uses the same wiring in the power mode which joeqsmith suggested for the 121GW.

Thanks for the post.  I had not thought about the Gossen Energy.   
How electrically robust is your meter?? https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 

Offline darik

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Re: EEVBlog 121GW Discussion thread
« Reply #1404 on: February 21, 2019, 10:15:28 pm »
I did some experiments on power measurement with the 121GW and I observed the "correct" way to connect it to measure power consumed by a load resulted in a negative display value for the power.

At first I didn't like this, but actually you could argue that power consumed is negative and power produced is positive. So perhaps it is just a matter of human perspective rather than any technical limitation of the system?

Understanding how it works, I'm okay with this implementation. But I'm sure glad I don't have to write the documentation to explain it to someone else.
 

Offline 2N3055

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Re: EEVBlog 121GW Discussion thread
« Reply #1405 on: February 21, 2019, 10:32:43 pm »
Metrix MTX3293 actually shows negative VA in secondary VA mode... For instance it will show 5V, -100mA and -500mVA..
But it will be correct.
 

Offline joeqsmith

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Re: EEVBlog 121GW Discussion thread
« Reply #1406 on: February 22, 2019, 01:25:11 am »
Metrix MTX3293 actually shows negative VA in secondary VA mode... For instance it will show 5V, -100mA and -500mVA..
But it will be correct.

I just DLed the manual for this meter.  Interesting enough, they don't provide many details for the VxA mode.  There are no recommendations on how to connect it that I saw and there was no mention about the burden voltage when using this mode.   I then looked for a video showing it but I only found one.  The guy really doesn't provide any details other than to say how nice he thought it was.      Is there an application note or better manual available for this meter?

https://youtu.be/BtlWO8TIkO8
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Offline 2N3055

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Re: EEVBlog 121GW Discussion thread
« Reply #1407 on: February 22, 2019, 07:40:36 am »

I just DLed the manual for this meter.  Interesting enough, they don't provide many details for the VxA mode.  There are no recommendations on how to connect it that I saw and there was no mention about the burden voltage when using this mode.   I then looked for a video showing it but I only found one.  The guy really doesn't provide any details other than to say how nice he thought it was.      Is there an application note or better manual available for this meter?

Hi Joe!
Yes, not much data about that instrument in general. You are correct, no explanation in manual for connection. There are only two ways to connect it though, and only one that gives correct reading, and I 'we been using it like that since day one, not giving it much thought about it. Apparently it is not that obvious... And as I said, instrument shows power drain with correct sign.
Anyways, i shot an E-mail to support at Chauvin Arnoux to clarify connections and a suggestion to add it the manual. We'll see if and how they will respond.

Regards,
Siniša
 

Online beanflying

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Re: EEVBlog 121GW Discussion thread
« Reply #1408 on: March 02, 2019, 03:30:30 am »
Playing with my new (to me) Fluke 335D DC Calibrator and I decided to grab the 121GW out and hook it up as I haven't done any high voltage DC testing with it (100V max in the past).

Also just for interest I used both the Android and the Windoze Apps via Blutooth to record the information. Phone was handheld maybe 1m away and the PC is more like 3m away and uses a dirt cheap evilbay dongle. Both hooked up fine but the phone at one stage failed to connect until I power cycled the meter after being on the PC. Not an issue just noted if you are swapping connections.

As per previous testing on DC in particular my meter is well inside spec (0.05%+5 counts) I couldn't get it outside 2 counts of my Agilent from 100-600Vdc. Yes it is around 38C in my shack today but it is cooler than yesterday :phew:

At 100V it was reading 99.98V (worst % accuracy measured) against the Agilent which is 0.02% + 0 counts so a factor of 10 better than spec  :-+ Also clearly the Temp Co claimed for the meter is WRONG Complain Complain Complain .......  ::)

Beer time  :popcorn:
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Offline joeqsmith

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Re: EEVBlog 121GW Discussion thread
« Reply #1409 on: March 16, 2019, 04:55:17 pm »
Dave,

I just watched the latest mailbag.  You mention a new version of the 121GW and working towards getting your rotary switch life cycle tester working again.   I plan to do a full review of this meter which would include cycling the switch.  If you are interested, I would be be willing to buy a couple of these meters now (assuming you are happy with the other changes to the hardware) and run the test for you.   

It would be the 50K full cycle test like I have been running.   It would be non-stop unless something were to go wrong and I decided to abort the test.   


https://youtu.be/7iXwRlGDLmI?t=903
How electrically robust is your meter?? https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 
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Offline Cliff Matthews

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Re: EEVBlog 121GW Discussion thread
« Reply #1410 on: March 16, 2019, 05:11:57 pm »
That switch has been a nagging thing keeping me from buying.
 

Offline GeoffreyF

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Re: EEVBlog 121GW Discussion thread
« Reply #1411 on: March 16, 2019, 08:34:58 pm »
That switch has been a nagging thing keeping me from buying.

Have you compared the test results to your use and that of other meters?  What is true for them all is that switching modes while connected to a device you are testing, especially where there are higher voltages present, can blow a meter.

Meters in this price class are not considered to be forever investments either. If you really are using it, it will pay for itself in a few months. If you use it occasionally and without switching modes hot, you probably won't have a problem with the switch on this or any other meter in its class.
US Amateur Extra W1GCF.
 

Offline joeqsmith

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Re: EEVBlog 121GW Discussion thread
« Reply #1412 on: March 17, 2019, 12:21:15 am »
That switch has been a nagging thing keeping me from buying.

If they did address the problems with the switch and rolled in the other changes, I think it's good enough to give it another go.  It will be interesting to see if their changes to the mux and clamps improves it's ability to survive my low energy transients. 

When I was running all of these drift, noise, BT tests and developing the Labview interface for the prototype, I took it apart to tack a few wires to the PCB.  I noticed a fair amount of metallic debris around the contacts.  I had cleaned the meter early on but it appears to continue to wear.  Looking forward to seeing the improved version.
How electrically robust is your meter?? https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 

Offline joeqsmith

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Re: EEVBlog 121GW Discussion thread
« Reply #1413 on: March 20, 2019, 12:28:42 pm »
Dave,

I just watched the latest mailbag.  You mention a new version of the 121GW and working towards getting your rotary switch life cycle tester working again.   I plan to do a full review of this meter which would include cycling the switch.  If you are interested, I would be be willing to buy a couple of these meters now (assuming you are happy with the other changes to the hardware) and run the test for you.   

It would be the 50K full cycle test like I have been running.   It would be non-stop unless something were to go wrong and I decided to abort the test.   

I assume the lack of a response means it's not yet ready for prime time.  I'm in no rush.  Please let me know when they are available and the old stock has been flushed.  I don't see any reason to run the old version and want to make sure I get the latest hardware.   That's assuming that the shim was actually addressed.
How electrically robust is your meter?? https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 

Offline DavidWC

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Re: EEVBlog 121GW Discussion thread
« Reply #1414 on: March 20, 2019, 12:52:47 pm »
Hi everyone,

I'm a fellow 121GW owner and EEVBlog fan.  I'm also a programmer, and I'm trying to develop a mobile app that will work with a variety of BLE multimeters. 

For obvious reasons, I've started with the 121GW.  The name of the app is "Meteor", and I've released an early (beta) version to the iOS App Store:

https://itunes.apple.com/us/app/meteor-for-121gw/id1452124710?ls=1&mt=8

Here are the main differences in the v0.1 Meteor app vs. the EEVBlog 121GW app:

+ Control buttons available in landscape mode
+ Option for spoken measurements
+ Option for continuity buzzer
+ Dark mode option
+ Connect/disconnect button and disconnect-status labels
- Does not yet support multiple meters or math mode
- No in-app capture of samples (yet)

I wrote this initial version to look as much like the EEVBlog app as possible, so that it would be familiar to users and would allow me to compare its functionality to the first-party app.  It will, however, diverge in appearance as development continues.

The app is free, and I welcome feedback and suggestions.  As a v0.1 release, there are probably bugs and flaws.  Please report any bugs or issues to support@westerncomputational.com.

Regards,
David Lavo
david@westerncomputational.com
 
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Offline Cliff Matthews

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Re: EEVBlog 121GW Discussion thread
« Reply #1415 on: April 03, 2019, 02:31:02 pm »
KainkaLabs posted this YT vid today. For 10pF he'd be better off using an adapter rather than long gripper leads.
 

Offline bitwelder

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Re: EEVBlog 121GW Discussion thread
« Reply #1416 on: April 08, 2019, 07:58:56 pm »
What's the max safe temperature for the K-type temperature probe provided with the meter?
Manual says 1350 C, but that's about the probe itself.
What about the coating of the probe wiring?
 

Online beanflying

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Re: EEVBlog 121GW Discussion thread
« Reply #1417 on: April 08, 2019, 09:37:28 pm »
What's the max safe temperature for the K-type temperature probe provided with the meter?
Manual says 1350 C, but that's about the probe itself.
What about the coating of the probe wiring?

I wouldn't go above 250-300C in particular if the cable is resting on a hot surface. I used mine recently in the well of my Temperature Calibrator at 400C and the outer sheath was getting sticky. https://www.eevblog.com/forum/testgear/sika-18600e-dryblock-temperature-calibrator-teardown-pictures-testing/msg2249781/#msg2249781

« Last Edit: April 09, 2019, 01:20:12 am by beanflying »
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Offline rthorntn

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Re: EEVBlog 121GW Discussion thread
« Reply #1418 on: May 04, 2019, 01:00:13 am »
Hi All,

Sorry if I missed this but is the voltage and current for continuity test listed somewhere?

Someone is telling me that an STM32 can be damaged by DMM continuity checks...

Thanks.

Richard
 

Offline FrankBuss

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Re: EEVBlog 121GW Discussion thread
« Reply #1419 on: May 04, 2019, 01:10:45 pm »
Sorry if I missed this but is the voltage and current for continuity test listed somewhere?

Someone is telling me that an STM32 can be damaged by DMM continuity checks...

I don't know a full list, but here are some examples:

https://www.eevblog.com/forum/testgear/multimeter-with-low-continuity-test-voltage/

It can go up to 7.3 V for some multimeters like the Fluke 87V, but only 1 mA, so maybe not dangerous for the STM32.
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Offline FrankBuss

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Re: EEVBlog 121GW Discussion thread
« Reply #1420 on: May 04, 2019, 01:15:00 pm »
For the 121GW I couldn't find it in the manual, but see this page:

https://lygte-info.dk/review/DMMEEVBlog%20121GW%20UK.html

2.1 V open and 0.57 mA shorted.
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Offline J-R

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Re: EEVBlog 121GW Discussion thread
« Reply #1421 on: May 05, 2019, 08:03:54 am »
For the 121GW I couldn't find it in the manual, but see this page:

https://lygte-info.dk/review/DMMEEVBlog%20121GW%20UK.html

2.1 V open and 0.57 mA shorted.

I tested this with a pile of meters and can confirm those numbers: 2.111V - 2.115V and 0.571mA - 0.578mA.  There was a very large grouping around 2.111V, which I find interesting.
 
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Offline ggchab

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Re: EEVBlog 121GW Discussion thread
« Reply #1422 on: May 08, 2019, 07:43:38 am »
I bought the 121GW because it looked promising (and it is) but also because of some other points:
- heavily supported by Dave
- upgradable/hackable
- Dave's enthusiasm

Now, it seems that the "soufflé est retombé" as we say in French. I would like to be proven the opposite, but except a few apparitions of the multi-meter in some videos, enthusiasm seems to be gone, upgrades are no longer available, no more reaction from any Dave.

Available resources have probably moved to the micro supply ... until the next project ? May a small team support several projects and keep enthusiasm for all of them?

No offense at all, only my feeling... Buying the GW121 was my own decision, it's working, I use it and I don't regret it. I was just hoping a bit more.
 

Offline rthorntn

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Re: EEVBlog 121GW Discussion thread
« Reply #1423 on: May 08, 2019, 09:23:31 am »
I'm hoping the eevblog team are on holidays, I broke a probe tip 12 days ago, emailed them that same day and I haven't heard back from the team on how to replace it, fingers crossed they will come back rested and send me a response.
 

Online beanflying

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Re: EEVBlog 121GW Discussion thread
« Reply #1424 on: May 08, 2019, 09:33:58 am »
I'm hoping the eevblog team are on holidays, I broke a probe tip 12 days ago, emailed them that same day and I haven't heard back from the team on how to replace it, fingers crossed they will come back rested and send me a response.

It was New South Wales School Holidays until the 29th of April so you might be MIA in a block of Emails while Dave was doing Dad stuff. Worth a resend maybe?

I bought the 121GW because it looked promising (and it is) but also because of some other points:
- heavily supported by Dave
- upgradable/hackable
- Dave's enthusiasm

Now, it seems that the "soufflé est retombé" as we say in French. I would like to be proven the opposite, but except a few apparitions of the multi-meter in some videos, enthusiasm seems to be gone, upgrades are no longer available, no more reaction from any Dave.

Available resources have probably moved to the micro supply ... until the next project ? May a small team support several projects and keep enthusiasm for all of them?

No offense at all, only my feeling... Buying the GW121 was my own decision, it's working, I use it and I don't regret it. I was just hoping a bit more.

The Firmware was never going to be open sourced but the Bluetooth is this was known before the kickstarter closed and maybe before? Seems there is a new Firmware available making it maybe the third?? (haven't checked) upgrade since the start of the year? I am sure it will be available sooner rather than later like all the others.

What were you expecting? Personally I feel the firmware is likely approaching the limits of the hardware so incremental change will naturally slow and be minor in nature.
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