Author Topic: EEVBlog 121GW Multimeter Firmware Details  (Read 70056 times)

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Offline CDaniel

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Re: EEVBlog 121GW Multimeter Firmware Details
« Reply #175 on: December 03, 2018, 08:11:12 am »
I have Keysight U1273A...does that have HY3131?

Yes , it should have HY3131 , but I think you can easily take a peek inside to confirm .

« Last Edit: December 03, 2018, 08:12:46 am by CDaniel »
 

Offline ChrisG

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Re: EEVBlog 121GW Multimeter Firmware Details
« Reply #176 on: December 03, 2018, 10:51:46 am »
I upgraded the 121GW regularly and now from 1.51 to 1.57 it's done. It stuck for 20 minutes without any progress. So I did need to switch it off (sorry). Wanting to go back to 1.51 is to no avail and it seems bricked now. What should I do? What should I check? The download option is still available though.
 

Offline GeoffreyF

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Re: EEVBlog 121GW Multimeter Firmware Details
« Reply #177 on: December 03, 2018, 12:56:53 pm »
I upgraded the 121GW regularly and now from 1.51 to 1.57 it's done. It stuck for 20 minutes without any progress. So I did need to switch it off (sorry). Wanting to go back to 1.51 is to no avail and it seems bricked now. What should I do? What should I check? The download option is still available though.

Did you leave the back off while you did this?
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Offline ChrisG

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Re: EEVBlog 121GW Multimeter Firmware Details
« Reply #178 on: December 03, 2018, 03:08:18 pm »
I tried both options. First it was on and then it was off. The batteries were still very good. However I thought I'd change them for the fun of it. No difference. Until..... I accidentally touched with the cover off with my hand the back of the SD card. I guessed it got wiggled side to side and presto.... (perhaps there is dust in?) On the other hand I've reinserted the card 10 times or more. Perhaps the gold-fingers of the slot are not that great ?
So I managed to do it in the end but this is a weakpoint in the design.
 

Offline GeoffreyF

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Re: EEVBlog 121GW Multimeter Firmware Details
« Reply #179 on: December 04, 2018, 02:52:57 am »
If the cover is not in place then the batteries are not securely in place. If the battery is interrupted for even a moment while loading, that would explain your issue.   Remove the cover and check how well the batteries stay in. You will see what I mean.

I had a close call on that myself once.  Keep the cover on when installing new firmware.
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Online Terry01

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Re: EEVBlog 121GW Multimeter Firmware Details
« Reply #180 on: December 04, 2018, 09:04:22 am »
I have Keysight U1273A...does that have HY3131?

Yes , it should have HY3131 , but I think you can easily take a peek inside to confirm .

Sorry was busy yesterday. I have a while today to spare. What was it you were wanting to see between these 2 meters again?
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Offline CDaniel

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Re: EEVBlog 121GW Multimeter Firmware Details
« Reply #181 on: December 04, 2018, 09:17:32 am »
I think everybody wants to know if the issues with 121GW ( from the issues topic ) are hardware related ( HY3131 limitations ) or software ( implementation ) , a direct comparison with a similar meter is usefull , maybe Keysight is worse , we don't know ...  :-\
« Last Edit: December 04, 2018, 09:25:07 am by CDaniel »
 

Online Terry01

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Re: EEVBlog 121GW Multimeter Firmware Details
« Reply #182 on: December 04, 2018, 09:31:57 am »
Ah ok, I can do that no probs at all but you'll have to just take my word for the results as I don't have any recording gear to make a decent video of the outcome.  :(
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Offline ChrisG

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Re: EEVBlog 121GW Multimeter Firmware Details
« Reply #183 on: December 04, 2018, 10:01:19 am »
Joe, I agree with you and the batteries were perfectly okay in the box and solid enough. I'm now wondering if I should retry with the former batteries although they seem perfectly fine. My take on things is that there is crud from the wipers on the SD card slot or the slot itself is not great.
 

Offline CDaniel

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Re: EEVBlog 121GW Multimeter Firmware Details
« Reply #184 on: December 04, 2018, 10:30:18 am »
Ah ok, I can do that no probs at all but you'll have to just take my word for the results as I don't have any recording gear to make a decent video of the outcome.  :(

Terry01 , we don't need proofs  , user observations and feeling is enough .
 

Online Terry01

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Re: EEVBlog 121GW Multimeter Firmware Details
« Reply #185 on: December 04, 2018, 01:50:23 pm »
Ah ok, I can do that no probs at all but you'll have to just take my word for the results as I don't have any recording gear to make a decent video of the outcome.  :(

Terry01 , we don't need proofs  , user observations and feeling is enough .

I spent 45 mins or so there with my 121GW and U1273a just measuring lots of different things between the two meters. I used 2 sets of the same leads in both meters depending what I was measuring. So the test was as fair as I could make it leads wise.
First off before I say anything when I first got the 121GW with firmware v1.54 installed I tested a load of resistors, caps, diodes and anything else I had laying around and I thought it wasn't that bad.

Today with it side by side with another meter it was awful! Very slow in everything apart from DC volts where it was ok or as good as the U1273a and it also jumps around quite a bit.
When measuring resistance it always jumps to between 20-40k and then settles on a more realistic number where the U1273a just lands on the measure and stays there solid.
On AC volts it's a wee bit slower than the U1273a but settles fine after a couple seconds.
I also measured the A ranges with a couple 9v batteries, 1 has been used a little and 1 is quite quite badly depleted which was very strange.
I used a 3.9 ohm power resistor as a load. Both meters showed around 87mA on the A range when measuring the newer battery but when i then changed range to mA range the 121GW would not read it and kept showing OFL where the U1273a measured it no problems in either A or mA. I found that very strange! The dud battery measured 200-300 uA or there abouts and both meters measured this no problems in the mA range.

When i tested the 121GW on it's own when i first got it it really didn't seem that bad, maybe my inexperience played a part in thinking that too though.

A couple things to sum up... the U1273a is around £100+ more expensive and has had time to iron out all the teething problems etc and also Keysight has much more experience and has made loads of previous other meters to gain knowledge from along the way. I think the 121GW will catch up in time but we'll just have to wait and see. I still use the 121GW at my bench just because i like the meter and a couple seconds extra to wait here and there doesn't matter to me.
I can see where it would matter to someone who needs quick measures dead on every time though. It's funny how a couple seconds extra makes the 121GW seem painfully slow beside the Keysight!  :)
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Offline CDaniel

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Re: EEVBlog 121GW Multimeter Firmware Details
« Reply #186 on: December 04, 2018, 03:50:39 pm »
Thx for the honest opinion , can you verify the autorange hysteresis ?
121GW has a huge hysterezis in resistance mode , switch in upper range at 55000 counts and  at 40000 counts in lower range , and very big in voltage mode 55000 counts up and 45000 down if I remember correctly .
« Last Edit: December 04, 2018, 03:56:59 pm by CDaniel »
 

Online Terry01

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Re: EEVBlog 121GW Multimeter Firmware Details
« Reply #187 on: December 04, 2018, 04:31:42 pm »
How do you mean? How would I test that to get the answer your looking for?

Sorry i'm still learning things...  :-[
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Offline CDaniel

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Re: EEVBlog 121GW Multimeter Firmware Details
« Reply #188 on: December 04, 2018, 04:53:04 pm »
With a power supply adjust the voltage up and down to see when is switching ranges .
For resistance you need a potentiometer or some kind of variable resistor .
Of course the multimeter must be left connected all the time , not adjust and then measure .
« Last Edit: December 04, 2018, 05:01:14 pm by CDaniel »
 

Offline Brumby

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Re: EEVBlog 121GW Multimeter Firmware Details
« Reply #189 on: December 05, 2018, 12:38:46 am »
With a power supply adjust the voltage up and down to see when is switching ranges .

To be clear here: 
Step 1: Use an adjustable power supply that can at least go from 3V to 7V.  Start at 3V or so and increase the voltage until you see the range change on the meter (watch the units and decimal point).  Make a note of the voltage when this happens.
Step 2: Continuing on from Step 1 - From the 7V level, decrease the voltage until you see the range change.  Make a note of this voltage.

The difference between these two voltages is the "hysteresis".  This is a designed behaviour meant to stop the frequent range changes you would get from a meter without this feature when a measured voltage fluctuates either side of the range switching point.

The issue is the magnitude of this hysteresis.  If it's too big then you could have a transient (for example) trigger a switch to a higher range and when the voltage settles it is under that "range up" switching point, but not below the "range down" switching point.  As well as being visually distracting, it also means you lose a whole digit of resolution.

This behaviour and the issues associated with it apply to all measurements and ranges - whether voltage, current, resistance or whatever.  I just used an easily achievable example for voltage.
« Last Edit: December 05, 2018, 12:43:09 am by Brumby »
 

Online Terry01

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Re: EEVBlog 121GW Multimeter Firmware Details
« Reply #190 on: December 05, 2018, 08:29:54 am »
With a power supply adjust the voltage up and down to see when is switching ranges .

To be clear here: 
Step 1: Use an adjustable power supply that can at least go from 3V to 7V.  Start at 3V or so and increase the voltage until you see the range change on the meter (watch the units and decimal point).  Make a note of the voltage when this happens.
Step 2: Continuing on from Step 1 - From the 7V level, decrease the voltage until you see the range change.  Make a note of this voltage.

The difference between these two voltages is the "hysteresis".  This is a designed behaviour meant to stop the frequent range changes you would get from a meter without this feature when a measured voltage fluctuates either side of the range switching point.

The issue is the magnitude of this hysteresis.  If it's too big then you could have a transient (for example) trigger a switch to a higher range and when the voltage settles it is under that "range up" switching point, but not below the "range down" switching point.  As well as being visually distracting, it also means you lose a whole digit of resolution.

This behaviour and the issues associated with it apply to all measurements and ranges - whether voltage, current, resistance or whatever.  I just used an easily achievable example for voltage.

Thanks for the explanation. I understand now what hysteresis is and can do this later this morning and will post the results.

Is anyone else having the problem I had yesterday with their meter not measuring in mA range? My 121GW was measuring 87mA in the A range but when I changed range to mA it would not measure. It kept showing OFL.  :-\

I have v1.54 firmware installed as it came from Welectron around a week ago.
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Offline ChrisG

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Re: EEVBlog 121GW Multimeter Firmware Details
« Reply #191 on: December 05, 2018, 10:31:38 am »
If the cover is not in place then the batteries are not securely in place. If the battery is interrupted for even a moment while loading, that would explain your issue.   Remove the cover and check how well the batteries stay in. You will see what I mean.

I had a close call on that myself once.  Keep the cover on when installing new firmware.

Good idea.  I ran the meter a fair amount with the back cover removed in order to have access to the SD card and have not had a problem with them falling out but I normally have the meter face up and flat down on the table.    If the battery is pulled, I would expect the meter to have no problems.  I assume the boot loader runs a CRC on the application area before trying to run it.  If it fails, it should just wait for the new image to be loaded.   It sounds like there is a fear that the meter actually has been bricked doing this.   So, do we know if this is actually a problem or not?

I do not know this no. What I could do is start to retest and check and fiddle around with other FW updates with the risk that I eventually brick it. So mwahhhh not sure. Also my selector knob is still quite crusty in terms of rotation and not up to standard for a 239.00 € item IMHO. In other words the shim solution did fix one thing and made something else worse. I do like the meters form factor, options, features though and I believe we should continue to develop on this going to version 2.0 in 2019 or so.
 

Offline exe

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Re: EEVBlog 121GW Multimeter Firmware Details
« Reply #192 on: December 05, 2018, 11:32:45 am »
Is anyone else having the problem I had yesterday with their meter not measuring in mA range? My 121GW was measuring 87mA in the A range but when I changed range to mA it would not measure. It kept showing OFL.  :-\

Did you change the current socket on the meter?
 

Offline exe

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Re: EEVBlog 121GW Multimeter Firmware Details
« Reply #193 on: December 06, 2018, 02:57:56 pm »
If anyone has bricked one from upgrading the firmware, chime in.

Uhm, it's a standard stm32 mcu, can be reprogrammed via the swd intarface using a $5 programmer (but header is not soldered). I did brick it many times and was able to restore the original firmware and bootloader. Just be sure to dump the calibration table, I lost mine during experiments.
 

Online Terry01

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Re: EEVBlog 121GW Multimeter Firmware Details
« Reply #194 on: December 06, 2018, 05:38:54 pm »
Is anyone else having the problem I had yesterday with their meter not measuring in mA range? My 121GW was measuring 87mA in the A range but when I changed range to mA it would not measure. It kept showing OFL.  :-\

Did you change the current socket on the meter?

Yes, just did it again and also with my 87v too. The Fluke did it no probs and the 121GW showed OFL. I used a half-"ish" used 9v battery and a 4 ohm power resister as a load.
I have another much more depleted 9v battery that is down to 200-300 uA using the same set up. Both meters measured this no problem.
I have just read that you are not supposed to use fresh lithium in the 121GW which i have so it may be my fault. I'll change them out later for normal batteries and see if it fixes it.
I'll let you know how I go with that.
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Offline HKJ

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Re: EEVBlog 121GW Multimeter Firmware Details
« Reply #195 on: December 06, 2018, 05:44:09 pm »
Yes, just did it again and also with my 87v too. The Fluke did it no probs and the 121GW showed OFL. I used a half-"ish" used 9v battery and a 4 ohm power resister as a load.

You are aware that maximum for mA input range is 55mA on the 121GW, for larger current you must use the A input.
 
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Online Terry01

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Re: EEVBlog 121GW Multimeter Firmware Details
« Reply #196 on: December 06, 2018, 05:50:05 pm »
Well there's why it won't measure 90 mA in the mA range then!   :-DD
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Offline HKJ

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Re: EEVBlog 121GW Multimeter Firmware Details
« Reply #197 on: December 06, 2018, 06:40:23 pm »
Well there's why it won't measure 90 mA in the mA range then!   :-DD

That is part of the "Low burden voltage", the high mA range is moved to the A input.

It is not that the meter is missing a range, it has one or two current ranges more than most other multimeters. It has 7 current ranges, typically a meters has 5 or 6 current ranges.
 

Online Terry01

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Re: EEVBlog 121GW Multimeter Firmware Details
« Reply #198 on: December 07, 2018, 02:44:22 pm »
Well there's why it won't measure 90 mA in the mA range then!   :-DD

That is part of the "Low burden voltage", the high mA range is moved to the A input.

It is not that the meter is missing a range, it has one or two current ranges more than most other multimeters. It has 7 current ranges, typically a meters has 5 or 6 current ranges.

Cool, thanks for the information. I would never have guessed that as there is no indication on the meter around the jacks and I haven't read the manual.

Thanks again  :-+
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Offline HKJ

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Re: EEVBlog 121GW Multimeter Firmware Details
« Reply #199 on: December 07, 2018, 03:08:08 pm »

Cool, thanks for the information. I would never have guessed that as there is no indication on the meter around the jacks and I haven't read the manual.

There is a indication, the A terminal is marked "A 500mA", because it is both ampere and 500mA range.
 


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