EEVblog 121GW Multimeter Issues

[bryanp]

Hi Dave (and everyone else),

I have done a search on the forums for a dedicated 1212GW support thread but could not find one, apologies if I have missed it.

I just received my 121GW and it is awesome. I was looking over the set up menu to set the date and time etc but am having a few issues.

1. If I change the year (it defaults to 2016), the day, month, hour or minutes the setting does not stick/save. Changing (and having them save) other set up menu items works fine. I have tried cycling the power on the meter after making a change but that has no effect.

2. Is it possible to disable the beep please, at least for button presses and any time the rotary switch is changed? The beep is loud which is great for continuity etc but after trying to figure out how to change the date/time it is starting to annoy.

3. There appears to be a set up menu option between item 7 (Hour-Minute) and item 8 Logging Interval. This set up menu item is not mentioned in the manual, and it is present on at least the Low Z, V and Ohms ranges. The set up menu item consists of 5 digits, it seems to default to 5 zeros but these numbers can be changed from 0-9 and once you hold down the setup button to edit this option you can use the set up button to switch between each digit. I do not know what these numbers/digits mean. I changed the last digit (on the right hand side) to a value and saved it but this seemed to have no effect.

4. An erratum for the manual in regards to changing the Hour-Minute and Month-Day set up menu items should include some mention of a long setup button press to switch between month and day for instance and a short setup button press to save and move on. This functionality seems to be the opposite to the five zeros set up menu item (mentioned above) as a short press switches between zeros/digits and a long press saves and switches to the next set up menu item.

Please let me know if I am being an idiot and have missed something obvious.

Thanks and the meter really is a beast.

[EEVblog]

This is a thread for discussion of bugs and issues found with the 121GW meter.
Please state your version number.

[exe]

Hi Dave!

On my "U-1.01" low z doesn't work until voltage reaches 11V. Then it works fine (but shows only one digit after dot (like 11.3V), intentionally low resolution?).

Update rate is like 0.5samples/s. Tried to change "In x" (by default it's ln 0), no luck.

[amspire]

1. If I change the year (it defaults to 2016), the day, month, hour or minutes the setting does not stick/save. Changing (and having them save) other set up menu items works fine. I have tried cycling the power on the meter after making a change but that has no effect.

Just got my meter today, and I am very impressed. Calibration is pretty much spot on.

The time/date works fine on my meter (version U-1.01). It arrived with the correct time and it seems to keep correct time even after changing the batteries. 

After changing a time/date field, are you pressing the setup button for about two seconds until the beep to save the change?

[DrGeoff]

1. If I change the year (it defaults to 2016), the day, month, hour or minutes the setting does not stick/save. Changing (and having them save) other set up menu items works fine. I have tried cycling the power on the meter after making a change but that has no effect.

Confirmed. I have 2072-06-12 as the default date and changing it does not save.
Time does not save correctly either.

2. Is it possible to disable the beep please, at least for button presses and any time the rotary switch is changed? The beep is loud which is great for continuity etc but after trying to figure out how to change the date/time it is starting to annoy.

Yes please!

[bryanp]

Thanks amspire for the help, I tried the long setup button press and the date and time etc changes were saved. Could have sworn I tried that yesterday but thanks.

My version number BTW is also U-1.01

Still not sure what the five digits thing is in the set up menu between the Hour-Minute and Logging Interval is. Does anyone else have this extra set up menu item?

[DrGeoff]

After changing a time/date field, are you pressing the setup button for about two seconds until the beep to save the change?

I missed that, not in the manual, just 'press setup'. Date/time appears set OK now that I hold setup down for an extended time.

Thanks!

[amspire]

1. If I change the year (it defaults to 2016), the day, month, hour or minutes the setting does not stick/save. Changing (and having them save) other set up menu items works fine. I have tried cycling the power on the meter after making a change but that has no effect.

Confirmed. I have 2072-06-12 as the default date and changing it does not save.
Time does not save correctly either.

Are you saying that if you change the year to 2018 and hold the setup button down till the beep, then if you check the year again, it is back to 2072?

[DrGeoff]

1. If I change the year (it defaults to 2016), the day, month, hour or minutes the setting does not stick/save. Changing (and having them save) other set up menu items works fine. I have tried cycling the power on the meter after making a change but that has no effect.

Confirmed. I have 2072-06-12 as the default date and changing it does not save.
Time does not save correctly either.

Are you saying that if you change the year to 2018 and hold the setup button down till the beep, then if you check the year again, it is back to 2072?

Yes, I cycled through all the date/times and set them. Then cycling back to the year again it was unchanged. There must be a difference between pressing the Setup button to cycle to the next setup option and holding it for longer to save the current value. The manual was not clear on this.

To change the date items:
1. Navigate to the menu item.
2. Hold SETUP
3. Press UP and DOWN to configure the date/time item.
4. Press SETUP again to save

[amspire]

Yes, I cycled through all the date/times and set them. Then cycling back to the year again it was unchanged. There must be a difference between pressing the Setup button to cycle to the next setup option and holding it for longer to save the current value. The manual was not clear on this.

To change the date items:
1. Navigate to the menu item.
2. Hold SETUP
3. Press UP and DOWN to configure the date/time item.
4. Press SETUP again to save

You have to hold the setup button for 2 seconds until the beep to change the date/time settings. Otherwise it is not changed. I don't think it does clearly say that in the manual.

[DrGeoff]

Also, as an aside, if you hit 'Setup' in the AC volts display you get dBm in the smaller top display.
Very useful.

[amspire]

Looks like full scale of the 121GW is 54999 and not 49999 - which is fantastic.  The specifications in the manual probably should be updated to mention this.

[exe]

BTW, is there a source code so I could try fix some problems by myself? (sorry if this was asked before)

[amspire]

The source code for the Bluetooth 121GW App is available. The code for the Multimeter will likely never be open source according to Dave.

[mikeselectricstuff]

The source code for the Bluetooth 121GW App is available. The code for the Multimeter will likely never be open source according to Dave.

But I suspect someone will disassemble it at some point...

[Fungus]

The source code for the Bluetooth 121GW App is available. The code for the Multimeter will likely never be open source according to Dave.

But I suspect someone will disassemble it at some point...

IIRC the point of not open-sourcing it is that messing with the firmware could affect the safety of the meter so there's no way they can officially sanction that or help people to do it.

If you want to mess around with it, that's your problem, not theirs.

(And I hope you make people aware of this problem if you start uploading modified firmware somewhere)

Edit: The best course of action if you want something "fixed" is to ask here. Dave could maybe pass sensible requests along to the manufacturer...

[exe]

IIRC the point of not open-sourcing it is that messing with the firmware could affect the safety of the meter so there's no way they can officially sanction that or help people to do it.

Is it a law or requirement? Or they try to be on a "safe" side?

[exe]

Opened the manual, it says "This meter is hackable, go for it.". Challenge accepted 

[mikeselectricstuff]

The source code for the Bluetooth 121GW App is available. The code for the Multimeter will likely never be open source according to Dave.

But I suspect someone will disassemble it at some point...

IIRC the point of not open-sourcing it is that messing with the firmware could affect the safety of the meter so there's no way they can officially sanction that or help people to do it.

Do the IEC test equipment standards actually cover software funcitionality ( e.g. not under-reading)?

[bicycleguy]

FYI
Possible bugs in User's Manual (Rev 11 December 2017):
1.  No mention of input impedance for any V inputs.
2.  No mention of Low Z position on dial.

[beanflying]

Slow Auto Ranging.

Manually set Range response time is great. So if you are testing a batch best to lock it in.

Without knowing how the code is written but checking out the bottom of the display shows it start at MOhms then cycle down through the ranges until it get into limits, it then seems to run a stepped routine to decide where to place the decimal point before displaying a value? Remove display indicators and anything not absolutely necessary to make the auto range work well and safely to improve the speed. So some firmware code optimization needed if possible?

[lowimpedance]

Minor update for the next manual revision; The main photo needs updating to show the 500mA text over the 'A' terminal and the Bluetooth symbol is missing between the 'SETUP' an '1mS PEAK' buttons.
Manual I am looking at was last revised 11th Dec.

[VK5RC]

+1 re the relative slowness of auto-ranging, otherwise very happy

[beanflying]

Yes, I cycled through all the date/times and set them. Then cycling back to the year again it was unchanged. There must be a difference between pressing the Setup button to cycle to the next setup option and holding it for longer to save the current value. The manual was not clear on this.

To change the date items:
1. Navigate to the menu item.
2. Hold SETUP
3. Press UP and DOWN to configure the date/time item.
4. Press SETUP again to save

You have to hold the setup button for 2 seconds until the beep to change the date/time settings. Otherwise it is not changed. I don't think it does clearly say that in the manual.

Just playing with the settings on mine and yep. Manual needs to use the words "Long Press" or similar to save and to jump from the hours set to minutes.

Minor on the manual but the Index and Pages are out of step as no doubt more content has been added and will be

[exe]

BTW, I found the problem of slow updates. My meter came with "AC+DC" mode activated. In this mode it is very slow . And yeah, beeping sucks.