EEVBlog 121GW Discussion thread

[ElectricPower]

I am quite new here in the forum, but have read some in the multimeter thread regarding 121GW here and it seems there is a lot of error with it?

I wonder if I should order one, but became skeptical when I read the thread.

[Brumby]

I am quite new here in the forum, but have read some in the multimeter thread regarding 121GW here and it seems there is a lot of error with it?

I wonder if I should order one, but became skeptical when I read the thread.

This thread provides a rather unusual connection between those who purchase a product and those involved in its development and production.  As such, all the personal preferences and minutae that any given owner may have can be aired directly - with the idea of influencing the development to suit them.  This is not something I have ever seen with ANY other commercial product.

As such, the voices here express a point that they feel is worth addressing - and while this may be a widespread concern, we can only be certain that it is a concern for those who have voiced it here.  One or two squeaky wheels here may not represent the concerns of the thousands who own and use this meter - who tend to just quietly work with the meter as supplied.

I would suggest you read the "issues" carefully and decide if anything mentioned would really affect you.  This is your homework.  You might normally have to go trawling around the net to find this information for any other product - but you have it encapsulated here.


Disclosure: I do not own a 121GW - not because of any the reports, but because I do not have the need.  My current equipment line-up covers more than I require at this time.

... but I AM interested.

[Doom-the-Squirrel]

Sorry if this has been asked before, but would the 121GW be a good choice for automotive electrical and electronics?

[EEVblog]

Sorry if this has been asked before, but would the 121GW be a good choice for automotive electrical and electronics?

Not really.
A simpler less precise meter would be a better choice, like a BM235 or an Automotive variant of that:
https://brymen.eu/shop/bm319s/

[firewalker]

I teach electronics to automotive technicians. They are in a stage that they can use a DMM to measure sensors etc with ease. I gave them 121GW to use for a change. After 5 minutes the wanted to break it. 

Alexander.

[EEVblog]

I teach electronics to automotive technicians. They are in a stage that they can use a DMM to measure sensors etc with ease. I gave them 121GW to use for a change. After 5 minutes the wanted to break it. 

Yes, the more rugged BM235 is more suited to field and automotive use IMO.
And if you need the features of an automotive meters like tacho/dwell then you need a specific automotive model.
Best to start a new thread asking for the best automotive meter.

[in06khattab]

Is it possible to silence the beep in continuity mode and use the screen flashing as an indicator?

[jancumps]

Is it possible to silence the beep in continuity mode and use the screen flashing as an indicator?

No. You can switch the beeper on or off, but for continuity, it will always beep. The screen does not flash.

[dr.diesel]

Is it possible to silence the beep in continuity mode and use the screen flashing as an indicator?

This would be a great feature!

How about a config file on the SD card as well for custom options:

continuityflash=1
autopoweroff=45
ble=1
defaultDCVrange=2

etc

[in06khattab]

Surely, that is a simple software update?
This can be enabled in the setup menu.
Then if the buzzer sounds, flash the screen.

If the firmware was available, this is very easy to add (without the setup menu).

[EEVblog]

17 units of the old kickstarter build stock left, 20% discount off the already sale price on the EEVblog website, coupon code fluxcapacitor
https://www.eevblog.com/product/121gw/

[Brumby]

Geez....  Now you're really tempting me - but I have to take care of the Christmas budget first.


(Not to mention the reaction I will get if I bring another multimeter into the house  )

[BrianG61UK]

17 units of the old kickstarter build stock left, 20% discount off the already sale price on the EEVblog website, coupon code fluxcapacitor
https://www.eevblog.com/product/121gw/

What improvements are we missing out on if we choose to save by getting one of these old build 121GWs?

[BVH]

Is there a new 20% off for Christmas coupon code available?

[popol]

Hi,

I'm busy looking at the 121GW schematic, and I have some questions.

On the set "Burden", what is the component FB2 BEAD ??
See link :



It's a capacitor? or another type of room? If anyone knows what it is,

Witch value have this component ?

thanks for the answer.

[Grandchuck]

A ferrite bead?

[gdewitte]

Ferrite bead (another one at FB3). https://www.analog.com/en/analog-dialogue/articles/ferrite-beads-demystified.html#

[popol]

Ok, thank-you for your response. But witch are caracteristics of this component ( uH, pF, Ohms ? )

[CDaniel]

I don't think inductance is very important like in a normal LC filter , after all is just a very short wire , but the ferrite is made "lossy" ( hysteresis losses ) so high frequency is "consumed" inside .

[ejeffrey]

The document gdewitte linked to shows some typical impedance vs. frequency curves, but a typical ferrite bead has very low impedance at low frequency -- basically just a short wire, and then cuts on with a very low Q inductance (i.e., mostly resistive) at higher frequency, typically several MHz to several hundred MHz.  Far above anything a multimeter cares about.  Their purpose is to limit EMI pickup from external sources (like FM radio) and also to prevent emissions of internally generated high frequencies such as from digital electronics and switching power supplies.  If chosen at all appropriately they have negligible effect on the actual desired signal.

[popol]

Ok, its clear now, thank-you for your response.

[npelov]

Yesterday I gave up on logging onto the SD card and tried the android app - it worked fine for a while - I could save the data in csv. But then after about one hour the save button did not work any more. If I press save nothing happens.
The last time I was able to save something was at the 50 minute mark. I pressed the save button and because nothing happened in a second or two I pressed it again. Then the usual share dialog appeared, but when I saved the file another share dialog appeared - I guess it was just taking it's time.

And it's a separate thing I can't save the csv file on the phone itself - I can only put it in an email, google drive and other things that usually popup in "share file".

Is there any way to log data with this DMM in a stable way?

You would think that a DMM advertised as "logging" would be able to log and after an year and a half the major bugs would be fixed. I'm sorry Dave but you are nip-picking other products for much smaller flows. I know you are not directly responsible for the firmware, but you should be more pressing. Your name is on the meter.

BTW the 500mA range is unstable. Sometimes I get quite a bit of noise. I'll be back later with numbers, because I forgot how much it was jumping around. I think I was in fixed 500mA range measuring 10mA. I think it's not like that all the time, but I'm not sure. I'll try to investigate more. The low burden is pushing the limits a bit but I think there is more to it, because sometimes it's relatively stable.

[joeqsmith]

Is there any way to log data with this DMM in a stable way?

When I tried their Windows 10 software, it wasn't very smooth to use.    Maybe it works better now and would allow you to make longer logs.   The last test I ran with the meter I was logging for about a day and a half using 2.02 firmware.  This is using LabView, not their software.    However, after seeing the problems with the SD card, I wonder if the BLE would have the same problem.  Most of the tests I have ran using the 121, I was looking at drift, noise... so the input was stable.     

https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg2839508/#msg2839508

[npelov]

The BLE reflects the display. The display was fine when the SD card log showed non sense. Also BLE sends at a rate independent of SD cart log interval. I feel like the bug is just in the SD card write routines. I selected 10 seconds  for the last try - logging both SD card and android app. I logged for a few hours and the DMM froze. Just before freezing it looked like this:


The second display shows 5dE04 ... while it was still recording. It should be showing the record number. The last record number in the SD log is 1140. Last voltage 10.345V (you can see on the android app 10.190V), last power 17.03VA, note that it's 16.74 on the display.  So the log stopped a while ago. I was measuring 12V/9Ah battery discharge on a 20W car bulb, so the power gets lower with the voltage.

Then it frose like this and only turn off fixed it:

The SD card log was good this time, but it was for just few hours at 10 second interval.

The android app save button didn't work. I guess it has too many records.

[npelov]

The hanging part has nothing to do with using the SD card and BLE at the same time. It happened before, but I don't remember the circumstances. I think it was again on VA, but I'm not sure.

You are right about the logging equipment, but the whole idea of buying this DMM is using it for it's special features - BT, SD logging, low burden voltage, and they all don't work reliably.