Author Topic: New EEVBlog-Branded Multimeter Coming?  (Read 113168 times)

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Offline Jon.C

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Re: New EEVBlog-Branded Multimeter Coming?
« Reply #225 on: July 29, 2017, 04:25:16 am »

 :popcorn:

 

Online coromonadalix

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Re: New EEVBlog-Branded Multimeter Coming?
« Reply #226 on: July 29, 2017, 12:39:46 pm »
oh hooooo  good news   gonna kick start again loll
 

Online 2N3055

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Re: New EEVBlog-Branded Multimeter Coming?
« Reply #227 on: July 30, 2017, 12:58:51 pm »
Well,
looking at the numbers from Dave's short video I calculate like this:

                          temp                       121GW                      Gossen                     U1282A
---------------------------------------------------------------------------------------------------------------------
room                  22,60 °C                  4,5001 V                   4,5006 V                   4,4999 V
test                    12,80 °C                  4,4996 V                   4,5011 V                   4,5005 V
Temp diff            -9,80 °C                  -0,0005 V                  0,0005 V                   0,0006 V

total err                                            -1111,09 ppm            1110,96 ppm             1333,36 ppm
                                                        -0,11%                     0,11%                       0,13%
---------------------------------------------------------------------------------------------------------------------
Tempco                                             113,38 ppm/°C         -113,36 ppm/°C         -136,06 ppm/°C
                                                        0,011%/°C               -0,011%/°C                -0,014%/°C
 

                        temp                         121GW                     Gossen                      U1282A
---------------------------------------------------------------------------------------------------------------------
room                   22,60 °C                   4,5001 V                   4,5006 V                   4,4999 V
test                   44,70 °C                   4,5000 V                   4,5005 V                   4,4987 V
Temp diff           22,10 °C                  -0,0001 V                  -0,0001 V                  -0,0012 V
total err                                            -222,22 ppm              -222,19 ppm             -2666,73 ppm
                                                        -0,02%                      -0,02%                     -0,27%
---------------------------------------------------------------------------------------------------------------------
Tempco                                            -10,06 ppm/°C            -10,05 ppm/°C          -120,67 ppm/°C
                                                       -0,001%/°C                -0,001%/°C               -0,012%/°C


Please someone correct me if I calculated wrong...

Also @joeqsmith, tempco is described in detail in Metrawatt Ultra datasheet. It is specified for Volts DC at 0,05%rdg+5d/10°K .. That comes out roughly to 50ppm/°K + some digits.
EDIT: In specs, you can see that it is specified from 0°C to 40°C. Your test at -20°C and 60°C is way out of instrument specification..
Manufacturer was very upfront that this meter perform to it's full spec in the laboratory and controlled temperature environments and we shouldn't expect it to perform much better than specified.. 

I would also not compare Joe's measurements with Dave's. Measuring in millivolt range introduces increased visibility all kinds of thermal effects in cabling and setup. I would expect that good portion of measured values comes from that influence. Measuring at 4.5 or 10 V is much better to suppress these kinds of errors and to concentrate on actual tempco of an instrument.

Looking at data for those two measurement points separately (room to -10°C, and room to +20°C) you can also see nonlinearities in tempco, that box method (min to max temp delta) doesn't show.

In order for tempco measurement to be useful, there should be measurement point every 10°C (or 5°C,  even better ) from 0°C to 50°C with soak time of 45min at every point.
It should be performed at 5-10V range to minimise cabling and setup tempco...

Best regards,

Sinisa

But considering this a  quick check, it seems so far that 121GW does pretty well, compared to more expensive meter..
« Last Edit: July 30, 2017, 01:06:59 pm by 2N3055 »
 

Offline EEVblog

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Re: New EEVBlog-Branded Multimeter Coming?
« Reply #228 on: July 30, 2017, 01:09:39 pm »
FYI
For reference, the prototype meter Joe has uses an LM385 reference and higher tempco spec divider resistors.
The latest real pre-production and production units have an ADR3412 reference and better tempco and aged divider resistors.?

Joe's results are not representative of a final unit.
I also didn't understand why Joe did a test at the extreme bottom end of the 50mV range. thermocouple effects in probe and contact dissimilar metals will likely dominate. This sort of testing should be done at close to full scale.
 

Offline 3db

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Re: New EEVBlog-Branded Multimeter Coming?
« Reply #229 on: July 30, 2017, 02:27:46 pm »
My guess is that Joe was just replicating the tests he did previously with other meters.
 

Offline evava

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Re: New EEVBlog-Branded Multimeter Coming?
« Reply #230 on: July 30, 2017, 07:51:51 pm »
... thermocouple effects in probe and contact dissimilar metals will likely dominate.

It only has to be explained why these effects dominate just at Gossen and do not dominate at UNI-T ..., if they really dominate.

I see Joes test as a temperature drift test (of near to zero readings) - what is so bad about it?
« Last Edit: July 30, 2017, 08:18:18 pm by evava »
 

Online joeqsmith

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Re: New EEVBlog-Branded Multimeter Coming?
« Reply #231 on: July 30, 2017, 08:47:10 pm »
My guess is that Joe was just replicating the tests he did previously with other meters.

That is correct.  I don't really care about the sources of the drift.  I just run them the same way and compare the results.  All of the meters I have looked at, once settled were sub 2mV total drift.

In order to avoid further confusion about the up and coming 121GW, I have removed all but the original video.  It seems having pre-production in the title and mentioning that throughout the videos and then explaining that I had even modified it, still did not mean that everyone would understand that this was not a production unit.   I assume Dave reviewed the original video of the set and gave me the thumbs up to make it public, so I plan to leave that one.
How electrically robust is your meter?? https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 
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Offline EEVblog

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Re: New EEVBlog-Branded Multimeter Coming?
« Reply #232 on: July 30, 2017, 11:00:11 pm »
I assume Dave reviewed the original video of the set and gave me the thumbs up to make it public, so I plan to leave that one.

Yes, I had no problem with the original video, as that was the intention of sending you one, to have some fun blowing one up, as you had requested, and what the users wanted in the forum poll.
Sorry I couldn't have sent you a final review unit, but that's just the nature of development, things are always changing until that production button is pushed.
 

Offline EEVblog

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Re: New EEVBlog-Branded Multimeter Coming?
« Reply #233 on: July 30, 2017, 11:09:36 pm »
... thermocouple effects in probe and contact dissimilar metals will likely dominate.
It only has to be explained why these effects dominate just at Gossen and do not dominate at UNI-T ..., if they really dominate.
I see Joes test as a temperature drift test (of near to zero readings) - what is so bad about it?

Nothing per-se if you want such a data point, so long as the thermocouple effects from junctions are consistent. Mostly you won't know what materials are used in the test leads and the contacts on the meters, so it could be a bit of a crap-shoot.
That's why if your goal is to characterise the tempco of a meter (that is mostly comprised of the reference + divider resistors), then you do it on the higher voltage ranges.
« Last Edit: July 30, 2017, 11:11:47 pm by EEVblog »
 

Online 2N3055

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Re: New EEVBlog-Branded Multimeter Coming?
« Reply #234 on: July 31, 2017, 12:09:49 am »
Nothing per-se if you want such a data point, so long as the thermocouple effects from junctions are consistent. Mostly you won't know what materials are used in the test leads and the contacts on the meters, so it could be a bit of a crap-shoot.
That's why if your goal is to characterise the tempco of a meter (that is mostly comprised of the reference + divider resistors), then you do it on the higher voltage ranges.

I can even understand that Joe wants to see influence of temperature on low ranges.. Including materials used..
I just suggested that testing at -20°C and 60°C is a bit extreme and out of specified working temperature ranges of most instruments.. And might have value as information how instruments handle operating them out of specs.. But you cannot correlate and compare  it to manufacturer published specification of tempco..
Testing them within specified range would be more useful, together with tempco curve.. For instance in your two point quick measurement it is obvious that 121GW and Gossen handle hot MUCH better than cold, while U1282A has almost linear negative tempco both hot and cold...

Regards,

Sinisa
 

Offline applepro

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Re: New EEVBlog-Branded Multimeter Coming?
« Reply #235 on: August 21, 2017, 03:03:15 am »

Hmm... so that's 3.33 months to 2.73 years.

Gee, I hope it's not the latter...  :-DMM

If you need to satisfy your DMM dependency quickly, you can order the EEVblog Brymen BM235 from amazon.com. Then, later, when you get the 121GW model, you will have a color matching pair.

 :)

Not sure about .com but Amazon.ca ran out of the BM235 earlier this month. :(
in stock now in .com and .ca maybe it because I have bought one 
 

Offline xani

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Re: New EEVBlog-Branded Multimeter Coming?
« Reply #236 on: September 11, 2017, 02:18:27 am »
So I was just re-watching the old episodes and stumbled upon this: https://youtu.be/0bzo7FdIkjc?t=176

No separate power button on 121GW!

Joking aside, is there a reason (except, well, sacrificing a button but that should not be a problem with >$100 meters) why so many multimeters do not have separate power buttons?
 

Offline EEVblog

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Re: New EEVBlog-Branded Multimeter Coming?
« Reply #237 on: September 11, 2017, 02:44:16 am »
Joking aside, is there a reason (except, well, sacrificing a button but that should not be a problem with >$100 meters) why so many multimeters do not have separate power buttons?

If you have a range switch anyway, then it costs nothing to add a power to to the PCB for that.
 

Online IanB

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Re: New EEVBlog-Branded Multimeter Coming?
« Reply #238 on: September 11, 2017, 02:55:38 am »
If you have a range switch anyway, then it costs nothing to add a power to to the PCB for that.

If you have a power button you can leave the meter on the range you most commonly use, which may also save some wear and tear on the range switch. It is probably a small thing, but it is a convenience, and it avoids the accident of turning the range switch to off while the meter is still connected (even if that may not be harmful to the meter, will it be harmful to the DuT?)
I'm not an EE--what am I doing here?
 
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Offline xani

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Re: New EEVBlog-Branded Multimeter Coming?
« Reply #239 on: September 11, 2017, 07:33:24 am »
If you have a power button you can leave the meter on the range you most commonly use, which may also save some wear and tear on the range switch. It is probably a small thing, but it is a convenience, and it avoids the accident of turning the range switch to off while the meter is still connected (even if that may not be harmful to the meter, will it be harmful to the DuT?)

I've bought cheapie with power button especially for that, so when I measure anything for longer I can just flip a power switch, even if meter lies in place that would cause it to slip if I turned the dial without holding it.

There is other reason too, if meter have jack that shares amps with anything you can have "accident" (altho that's pretty hard as amps ranges are usually furthest away from off position )
 

Online coromonadalix

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Re: New EEVBlog-Branded Multimeter Coming?
« Reply #240 on: September 15, 2017, 11:16:03 am »
is there some general specs of the meter available ??  even in the non final version ??     

For me the only thing i would hack is to remove the mv selection,  i measure lots of voltages, i need one range of AC and / or DC.

Im searching for a faster reading(s) meter like my gossen 28s, the newest metrahit ultra cost a mere 1200-1500$  here in Canada  outch,  boy i wish it could be like 3 -5 readngs a sec.

Never found anything close to it, while staying portable, and having at least 60,000 counts and up ...   I know about Metrix, to me they are ugly as hell and unpratical for me.

I really hope to buy the "Dave gw121" one loll
 

Online BU508A

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Re: New EEVBlog-Branded Multimeter Coming?
« Reply #241 on: September 15, 2017, 12:52:55 pm »
I really hope to buy the "Dave gw121" one loll

Can you hear this noise in the background? This kind of snorting and scratching with the hoofs?
This is the EEVBlog herd, waiting for the GW 121 to buy it.
Until one shouts "Look! The new GW 121! There you can buy it!" there will be a huge stampede happen...
 :-D

« Last Edit: September 16, 2017, 02:11:49 pm by BU508A »
“Chaos is found in greatest abundance wherever order is being sought. It always defeats order, because it is better organized.”            - Terry Pratchett -
 

Offline xani

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Re: New EEVBlog-Branded Multimeter Coming?
« Reply #242 on: September 17, 2017, 09:09:28 am »
For me the only thing i would hack is to remove the mv selection,  i measure lots of voltages, i need one range of AC and / or DC.

Must be a technical reason for it (as in having to physically switch some components in). Personally I'd switch continuity to be default mode when switching to ohms (or even having its own position if possible), I use it almost as often than measuring resistance
 

Online joeqsmith

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Re: New EEVBlog-Branded Multimeter Coming?
« Reply #243 on: September 17, 2017, 02:47:26 pm »
Im searching for a faster reading(s) meter like my gossen 28s, the newest metrahit ultra cost a mere 1200-1500$  here in Canada  outch,  boy i wish it could be like 3 -5 readngs a sec.

I picked up an Ultra but was not very impressed with it.  It has too many problems but maybe they will address them.  Hard to say as we never hear anything out of them.   
How electrically robust is your meter?? https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 

Offline Crumble

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Re: New EEVBlog-Branded Multimeter Coming?
« Reply #244 on: September 22, 2017, 09:56:58 pm »
Wouldn't a Brymen 869s do? It does read 5x/s. "Only" dual display though...
 

Offline EEVblog

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Re: New EEVBlog-Branded Multimeter Coming?
« Reply #245 on: September 22, 2017, 11:11:24 pm »
For me the only thing i would hack is to remove the mv selection,  i measure lots of voltages, i need one range of AC and / or DC.
Must be a technical reason for it (as in having to physically switch some components in). Personally I'd switch continuity to be default mode when switching to ohms (or even having its own position if possible), I use it almost as often than measuring resistance

The new firmware defaults to the last used mode. So you can leave it on continuity forever if you want, or AC volts default etc.
 
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Online coromonadalix

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Re: New EEVBlog-Branded Multimeter Coming?
« Reply #246 on: September 23, 2017, 11:19:38 pm »
niiice feature  continue the good work Dave
 

Offline Average Meatsack

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Re: New EEVBlog-Branded Multimeter Coming?
« Reply #247 on: September 26, 2017, 06:15:56 am »
Dave teased us with footage of the 121GW in use in his latest teardown video.

Big Meany!
 

Offline xani

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Re: New EEVBlog-Branded Multimeter Coming?
« Reply #248 on: September 26, 2017, 01:11:31 pm »
That's really neat way to do it, wonder if there is any other meter with last mode memory like it.

I hope we can get the meter before christmas :D
 

Online 2N3055

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Re: New EEVBlog-Branded Multimeter Coming?
« Reply #249 on: September 26, 2017, 02:01:29 pm »
That's really neat way to do it, wonder if there is any other meter with last mode memory like it.

I hope we can get the meter before christmas :D

Brymens are like that..
 


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