EEVblog 121GW Multimeter Issues

[Seppy]

I noticed the meter will auto-power off while in BT communication mode. I noticed this while logging some data and I wondered why the screen and graph froze. I suspect that auto-power off should be suspended while BT communication is enabled?

This is an option, at least manually, you can disable APo in the settings menu.

[IanB]

This is an option, at least manually, you can disable APo in the settings menu.

I appreciate this is an option, however it is a permanent setting, one way or the other.

The manual says, "APO is disabled in data logging mode." I suggest it would be an idea to disable APO during Bluetooth communications too, to facilitate Bluetooth data logging.

Also, some other meters have a way of temporarily disabling APO one time only, for example by holding down the MODE button when turning the meter on. This kind of feature would be useful.

[Bugsyson]

Long time reader first time poster. Received My 121gw (Thanks), and was playing around and found the burden voltage with firm ware V1.17  to be less than spot on, and totally not working with the new V1.21 firmware, only tested dc amps, (all ranges) so far.  Finger problems? On the plus side found Auto Hold to be working as well if not better than my Fluke 87V.

[Bugsyson]

Some Pic's.... Sorry limited by pic size due to under 25 posts

[IanB]

Long time reader first time poster. Received My 121gw (Thanks), and was playing around and found the burden voltage with firm ware V1.17  to be less than spot on, and totally not working with the new V1.21 firmware, only tested dc amps, (all ranges) so far.

I have never been able to make the burden voltage appear. How did you achieve that?

[Bugsyson]

With "bd.OFF" in upper display, hold setup till display blinks , select "be.ON" with REL or 1ms PEAK , hold setup button again till display blinks (beeps if you have that on) then press setup one more time to display "b  0.0 mV"

[ChunkyPastaSauce]

Quote from: Bugsyson on Today at 01:44:28 pm

Long time reader first time poster. Received My 121gw (Thanks), and was playing around and found the burden voltage with firm ware V1.17  to be less than spot on, and totally not working with the new V1.21 firmware, only tested dc amps, (all ranges) so far.

I have never been able to make the burden voltage appear. How did you achieve that?

With "bd.OFF" in upper display, hold setup till display blinks , select "be.ON" with REL or 1ms PEAK , hold setup button again till display blinks (beeps if you have that on) then press setup one more time to display "b  0.0 mV"

There is a bug (I think) in 1.17 and 1.21 where if you go from bd.off, switch mode to bd.on, and then press setup to apply without holding for some length (1/2-1 second), then i goes in to a weird state where it says bd.on but never actually displays burden voltage. Must hold setup button for some period.

[IanB]

With "bd.OFF" in upper display, hold setup till display blinks , select "be.ON" with REL or 1ms PEAK , hold setup button again till display blinks (beeps if you have that on) then press setup one more time to display "b  0.0 mV"

Thanks, got it.

I did a quick test and the voltage measurement looked reasonable. Did you remember to make a link between the VΩ terminal and the mA terminal? That link is needed to connect to the voltage measurement circuit inside the meter.

The 121GW measured 11.1/11.2 mV and the reference said 11.29 mV.

[Bugsyson]

Ah yes seems I forgot to put that jumper back in after updating to 1.21. Its seems more accurate than 1.17, also noticed it defaults to what ever mode you were in last, AC,DC when turning back on, instead of always DC, or like the fluke87V AC (bad). Thanks again for catching my finger problem.

[IanB]

There seems to be a problem with auto-ranging up from the 5 mA range to the 50 mA range. The meter seems to get confused and cannot lock into the reading. See video linked, where I have slowly ramped the current up from around 3 mA to around 30 mA. This is with firmware 1.21. Does anyone else see this?

https://youtu.be/AOJ8776Qg5Y

[ChunkyPastaSauce]

Quote from: IanB on Today at 05:55:29 pm

There seems to be a problem with auto-ranging up from the 5 mA range to the 50 mA range. The meter seems to get confused and cannot lock into the reading. See video linked, where I have slowly ramped the current up from around 3 mA to around 30 mA. This is with firmware 1.21. Does anyone else see this?

Yes, but only when burden volt mode is on; meter tries to switch out of the 5ma range to the 50ma range but gets stuck   edit FW V1.21

[Bugsyson]

Had the same auto ranging issue, also seem to have locked my meter up, reading 50mv all the time now (in A/mA rang), removed batteries no help, only thing that will make it go away is to put a banana plug into the mAuA jack.  Fuses good, never went above 100mA while playing around with the burden voltage. Went back to 1.17 also no help...

[Scottjd]

 Is there a change log for the new firmware 1.21?

[ChunkyPastaSauce]

Had the same auto ranging issue, also seem to have locked my meter up, reading 50mv all the time now (in A/mA rang), removed batteries no help, only thing that will make it go away is to put a banana plug into the mAuA jack.  Fuses good, never went above 100mA while playing around with the burden voltage. Went back to 1.17 also no help...

If software, there must be someway to do a factory reset? Settings seem to persist after pulling main and rtc batts and across firmware updates.

Is there a change log for the new firmware 1.21?

not yet afaik

[Seppy]

There seems to be a problem with auto-ranging up from the 5 mA range to the 50 mA range. The meter seems to get confused and cannot lock into the reading. See video linked, where I have slowly ramped the current up from around 3 mA to around 30 mA. This is with firmware 1.21. Does anyone else see this?

https://youtu.be/AOJ8776Qg5Y

Could you attempt the same test without the burden voltage measurement?
This is because when burden voltage measurement is switched on the multimeter alternates between voltage and current, this might be reseting the auto-ranging.

[ChunkyPastaSauce]

Could you attempt the same test without the burden voltage measurement?
This is because when burden voltage measurement is switched on the multimeter alternates between voltage and current, this might be reseting the auto-ranging.

I am seeing it too, but only when burden volt mode is on

[Seppy]

Had the same auto ranging issue, also seem to have locked my meter up, reading 50mv all the time now (in A/mA rang), removed batteries no help, only thing that will make it go away is to put a banana plug into the mAuA jack.  Fuses good, never went above 100mA while playing around with the burden voltage. Went back to 1.17 also no help...

What happens if you manually range to a different range?

[Bugsyson]

Had the same auto ranging issue, also seem to have locked my meter up, reading 50mv all the time now (in A/mA rang), removed batteries no help, only thing that will make it go away is to put a banana plug into the mAuA jack.  Fuses good, never went above 100mA while playing around with the burden voltage. Went back to 1.17 also no help...

What happens if you manually range to a different range?

See video, having a read through the cal procedure, do you think it may be possible it was cal's with a lead in the mA/uA jack?

[Seppy]

Had the same auto ranging issue, also seem to have locked my meter up, reading 50mv all the time now (in A/mA rang), removed batteries no help, only thing that will make it go away is to put a banana plug into the mAuA jack.  Fuses good, never went above 100mA while playing around with the burden voltage. Went back to 1.17 also no help...

What happens if you manually range to a different range?

See video, having a read through the cal procedure, do you think it may be possible it was cal's with a lead in the mA/uA jack?

Hmm, it seems that it flipped from manually ranged to auto ranged when you plugged in the jack. Can you manually range after the lead is plugged in.

[Bugsyson]

Yes can manual range in both cases, every time you cycle a plug into the jack it goes into auto range.

[Seppy]

Yes can manual range in both cases, every time you cycle a plug into the jack it goes into auto range.

It still displays 50 mA in both cases?
I suspect at some point your full scale range calibration for that range was calibrated while open circuit. Is this possible?

[Scottjd]

Yes can manual range in both cases, every time you cycle a plug into the jack it goes into auto range.

I can confirm this, it does reset to Auto when you cycle the plug. It’s also the reason that Auto Hold messed up with one of my tests. But I don’t know if the auto hold issues was worked on in the new firmware 1.21 since I came across a different error specifically to my meter in the 50M  range. I sort of gave up on testing for now since this one is a hardware issue. That’s why I was wondering if a change log was published for 1.21 firmware.
Scott

Edit:
I guess I should check that auto hold and 1.21 since I did promise to delete the video once it was resolved. I guess I’ll load the firmware tomorrow if I can.

[Seppy]

Yes can manual range in both cases, every time you cycle a plug into the jack it goes into auto range.

I can confirm this, it does reset to Auto when you cycle the plug. It’s also the reason that Auto Hold messed up with one of my tests. But I don’t know if the auto hold issues was worked on in the new firmware 1.21 since I came across a different error specifically to my meter in the 50M  range. I sort of gave up on testing for now since this one is a hardware issue. That’s why I was wondering if a change log was published for 1.21 firmware.
Scott

Change has not been added to manual, version was released over weekend haven't gotten to that yet, at the moment working on the iOS app with the Beta testers. The key change in 1.21 was that F and C were added to the bluetooth packet.
1.20 had some changes too I'll add that to the manual ASAP.

[Bugsyson]

Yes can manual range in both cases, every time you cycle a plug into the jack it goes into auto range.

It still displays 50 mA in both cases?
I suspect at some point your full scale range calibration for that range was calibrated while open circuit. Is this possible?

Have definitely not been in the cal mode, and it really thinks there is 50 extra mA, but only when plugged into the Amp Jack, readings are all good when using the mA/uA jack.

[Bugsyson]

What mode should I try and calibrate? Meter reads correct in all ranges and amp jack position except in "A" jack and in 500mA range which it auto ranges to, but reads the same when manually ranged.