Handheld meter robustness testing

[Fungus]

Not checked manuall, they for sure described this, but I noticed that 60000 counts is not a full '60000'.

That's the specification in the manual, yes, but in practice they do a lot better than that. Digital calibration means they're usually accurate down to the last digit or so.

(when they're at their calibration temperature...)

[2N3055]

And ... yet more confirmation that Brymen is the new king of multimeter manufacturers.

Fluke should bring back 189 to make market position harder to Brymen. That old 189 is still better than this new Brymen (neglecting the price)

Not checked manuall, they for sure described this, but I noticed that 60000 counts is not a full '60000'.
AC is cut to two digits after dot, the same for  resistance, same for current , that looks sometimes more like 6000 than 60000.
Actually e.g. 1mOhm resolution would be really very usefull.

F189 has multi display, logging, etc. It is better in features.

But can you explain what are you talking about 6000 digits?
Only time BM786 has 6000 digits is in Crest (high speed Min/max mode).

Also 1mOhm resolution is useless without 4w (Kelvin) measurements..

EDIT: what MiroS said, it seems that in some tests, BM786, when autoranging stayed in 600V AC mode, even when measuring 32 V. So that explains what MiroS said.
It definitely has 600mV, 6V and 60V AC range and it is full 60000 in all of them, but somehow it didn't autorange to those lower ranges, so 32, 35 and 40V was measured in 600V AC range.

[MiroS]

But can you explain what are you talking about 6000 digits?

All is about resolution e.g. for AC this will be 39.95 , but not 39.954V, e.g. for resistance it will be 28.04, but not 28.041 Ohms, e.g. for current 50.02 but not 50.025mA so really not different to a 6000 count multimeter.
I would not cry for AC volts , but actually 1mOhm resistance would be really very usefull.The same for AC current (10A socket).

[joeqsmith]

Interesting to see the Fluke 87V falling apart in tests where even a Uni-T keeps on going.   

Sorry, but I don't follow.  I showed the 87V with the new Brymen and Fluke 189.   I assume you are referring to the UT181A as it was the only UNI-T product I show in the video.   If you could explain your statement, I may be able to provide you with some insight.

[2N3055]

But can you explain what are you talking about 6000 digits?

All is about resolution e.g. for AC this will be 39.95 , but not 39.954V, e.g. for resistance it will be 28.04, but not 28.041 Ohms, e.g. for current 50.02 but not 50.025mA so really not different to a 6000 count multimeter.
I would not cry for AC volts , but actually 1mOhm resistance would be really very usefull.The same for AC current (10A socket).

No it is not like that. It is 60000 counts, BUT, for some reasons, on some measurements it didn't autorange to 60V AC range for 32V measurement, but stayed on 600V range, so it reads 032.00 V.

[HKJ]

No it is not like that. It is 60000 counts, BUT, for some reasons, on some measurements it didn't autorange to 60V AC range for 32V measurement, but stayed on 600V range, so it reads 032.00 V.

Was it the same ranges where there was a high AC voltage on the input?

[joeqsmith]

Fluke should bring back 189 to make market position harder to Brymen. That old 189 is still better than this new Brymen (neglecting the price)

I am guessing the market for a high end basic meter like this is very small.  Similar to the 289.   I understand that there was some diagnostics software written specifically for the 189.   The company that wrote it bought a lot of these meters.   That's in the past.     

There are cases where the Brymen 786 will outperform the 189 but again, its not anything that would concern me.   Overall though, I agree the 189 is a better meter.  Looks like I can still find stock. About $550 if you wanted a brand new one.   

[rsjsouza]

But can you explain what are you talking about 6000 digits?

All is about resolution e.g. for AC this will be 39.95 , but not 39.954V, e.g. for resistance it will be 28.04, but not 28.041 Ohms, e.g. for current 50.02 but not 50.025mA so really not different to a 6000 count multimeter.
I would not cry for AC volts , but actually 1mOhm resistance would be really very usefull.The same for AC current (10A socket).

No it is not like that. It is 60000 counts, BUT, for some reasons, on some measurements it didn't autorange to 60V AC range for 32V measurement, but stayed on 600V range, so it reads 032.00 V.

S
MiroS, Sinisa, indeed this is a weird behaviour and to me a bug. Sure, while Joe had the waveform with plenty of DC offset, I imagine there was a chance the autorange could be confused in ranges, but not after wards, where a pure AC was applied.

[joeqsmith]

But can you explain what are you talking about 6000 digits?

All is about resolution e.g. for AC this will be 39.95 , but not 39.954V, e.g. for resistance it will be 28.04, but not 28.041 Ohms, e.g. for current 50.02 but not 50.025mA so really not different to a 6000 count multimeter.
I would not cry for AC volts , but actually 1mOhm resistance would be really very usefull.The same for AC current (10A socket).

No it is not like that. It is 60000 counts, BUT, for some reasons, on some measurements it didn't autorange to 60V AC range for 32V measurement, but stayed on 600V range, so it reads 032.00 V.

S
MiroS, Sinisa, indeed this is a weird behaviour and to me a bug. Sure, while Joe had the waveform with plenty of DC offset, I imagine there was a chance the autorange could be confused in ranges, but not after wards, where a pure AC was applied.

Again, during the last test where the DC had been removed, the meter was set to VFD.  The bargraph will be disabled, the filter will be active causing a bit of an voltage difference for the higher frequency content waveforms and yes, it only displays two places past the decimal point.  We can see this on page 24. 

Is it worth repeating this test with the VFD disabled?   I could also just run two meter and remove the DSO, maybe slow it down a bit further to make it easier to track.   We could also increase the number of waveforms.  This test requires little effort to setup so if you feel it's worth it, let me know. 

I am still not sure what the comment was about UNI-T not having a problem.  I could toss the 87V into the mix as well if this is what you want to see.  It just gets more difficult for me anyway, to follow what is going on with so many devices active at once.

[2N3055]

Again, during the last test where the DC had been removed, the meter was set to VFD.  The bargraph will be disabled, the filter will be active causing a bit of an voltage difference for the higher frequency content waveforms and yes, it only displays two places past the decimal point.  We can see this on page 24. 

Is it worth repeating this test with the VFD disabled?   I could also just run two meter and remove the DSO, maybe slow it down a bit further to make it easier to track.   We could also increase the number of waveforms.  This test requires little effort to setup so if you feel it's worth it, let me know. 

I am still not sure what the comment was about UNI-T not having a problem.  I could toss the 87V into the mix as well if this is what you want to see.  It just gets more difficult for me anyway, to follow what is going on with so many devices active at once.

Hi Joe,

If it is not big effort and you're willing to do it, sure, it would be nice.
It would be nice to see limits of this, and maybe with what waveforms it will happen. I doubt autoranging will have problem with standard waveforms...
Maybe see it through full range (6V, 60V, 600V) ... Definitely check whether it is VFD related.

I personally don't think it is a major problem, it measures correctly, shows correct value, it simply didn't show max resolution. But it is not dangerous, like showing 4V when there is 232V being measured. And if you are measuring and this shows, you know what the problem is and can manually range if needed. That last digit is not accurate on AC anyways ...
But sure, if it can be fixed, it will be "betterer".

As for comparison with other meters, on that topic I have the opinion that you should strive to be as good as you can, not legitimize mediocrity by being as bad as others ("if Fluke doesn't do better, we don't have to" mentality...).  It might be educational to see how some other meters cope with it, just because it is not hard to simply add them into frame once you take effort to create setup.

Regards,

Sinisa

[MiroS]

Again, during the last test where the DC had been removed, the meter was set to VFD.  The bargraph will be disabled, the filter will be active causing a bit of an voltage difference for the higher frequency content waveforms and yes, it only displays two places past the decimal point.  We can see this on page 24. 

Is it worth repeating this test with the VFD disabled?   I could also just run two meter and remove the DSO, maybe slow it down a bit further to make it easier to track.   We could also increase the number of waveforms.  This test requires little effort to setup so if you feel it's worth it, let me know. 

I am still not sure what the comment was about UNI-T not having a problem.  I could toss the 87V into the mix as well if this is what you want to see.  It just gets more difficult for me anyway, to follow what is going on with so many devices active at once.

Hi Joe,

If it is not big effort and you're willing to do it, sure, it would be nice.
It would be nice to see limits of this, and maybe with what waveforms it will happen. I doubt autoranging will have problem with standard waveforms...
Maybe see it through full range (6V, 60V, 600V) ... Definitely check whether it is VFD related.

...

There was a comment on YT that BM869s has a problem with 560kOhm resistance measurement if it is performed close to power cord.  I would propose to add this to the list of tests if you will decide to make next tests with BM786.

[gnavigator1007]

Seems a follow up video for clarification might be worth it just for the sake of viewers that might not read the discussion here or dig thru the comments on the video.

[joeqsmith]

I'll repeat it using the same waveforms, but add a few more.  I will also run the same two voltage levels, but will also run it above 350.   I will run the video slower and will use the Fluke 189 and Brymen BM869s as a comparison.   I will leave the DSO out of it and overlay the labview application as before.   

There was a comment on YT that BM869s has a problem with 560kOhm resistance measurement if it is performed close to power cord.  I would propose to add this to the list of tests if you will decide to make next tests with BM786.

I responded to it but unless they provide details of what they were doing, I have no idea what they are going on about.  It's like the person here who claimed to have bought five Brymen meters that all failed the same way.   There's a point where you just can't help these people.   But because you have asked, what I will do is add a second BM869s.  I will wrap the leads around the HV lines feeding the meters and attach a 560Kohm resistor to it. 

... Definitely check whether it is VFD related.
...
But sure, if it can be fixed, it will be "betterer".

To me a standard waveform would be something like IEC413. 

There's nothing to fix.  Again it's documented in the manual. Yes, it is all to do with the VFD mode.   No big deal though to show it.  Give me a while to repeat it. 

[dcac]

Interestingly the BM786 LCD does seem to have a High Voltage warning symbol - but it's not mentioned in the manual and does never seem to be displayed either. Any particular reason for that? I think it's the same on BM869.

[dcac]

The BM786 Bar-graph does seems to have a strange behavior. Here it seems to be in 600.00V DC range but bar-graph would then correspond to 200 volts or so. Also note the DC is low but the BM786 seems to stay in the 600V DC as long as the overlayed AC is preset - it does not shift the range down to DC 5.0000V like the left Fluke 189.

[joeqsmith]

Could be a common display for them.  If you look at the manuals cover page, there are other symbols besides that one that they have removed.   T1-T2 would be nice to have.  I use that fairly frequently with the BM869s.  It's actually one of the reasons I bought my first Brymen! 

I ran the test...  This may be the easiest video to edit that I have ever made.   Won't be long.  If you would like it running at normal speed (uncompressed)  let me know.

[joeqsmith]

The BM786 Bar-graph does seems to have a strange behavior. Here it seems to be in 600.00V DC range but bar-graph would then correspond to 200 volts or so. Also note the DC is low but the BM786 seems to stay in the 600V DC as long as the overlayed AC is preset - it does not shift the range down to DC 5.0000V like the left Fluke 189.

Are you aware that the bargraphs auto range?  Full scale of 5 could mean 500V 50V 5V 500mV....

Now I see what you are getting at.  Yes, that bargraph would seem to be showing 200V.  I wonder if in these cases if the bargraphs range differs from the readout's.   

[2N3055]

To me a standard waveform would be something like IEC413. 

There's nothing to fix.  Again it's documented in the manual. Yes, it is all to do with the VFD mode.   No big deal though to show it.  Give me a while to repeat it.

Thank you for pointing this out. I went and read manual.. In VFD mode there is only 600 and 1000V range.
That does explain it..
As I said, I have no problem with that, VFD and LoZ are specialist modes.
I think meter is excellent as is.. I was slightly sarcastic, that's why I used word "betterer"...
Take care,
Sinisa

[joeqsmith]

AC Line test with the VFD turned off. 

[joeqsmith]

I have repeated the DCV test to see if I could replicate the problem with the bargraph.  It doesn't look like it locks up but rather that they calculate it differently than the readout.  It's really strange but easy to reproduce.  I have asked Brymen if they can fill us in on what it's doing.   

[dcac]

Interestingly the BM786 LCD does seem to have a High Voltage warning symbol - but it's not mentioned in the manual and does never seem to be displayed either. Any particular reason for that? I think it's the same on BM869.

Well, I was wrong about the BM869 - its LCD does not seem to have the High or rather ‘Hazardous’ voltage warning symbol.

That warning symbol probably isn’t a requirement by any safety standard. And I’m not suggesting Brymen is less safe or anything like that - I just noticed the BM786 LCD has a symbol for it - so perhaps Brymen has planes to implement it in the future.

[Cliff Matthews]

Good point. It would seem Brymen is listening, so maybe the BM786 will use it in the final release.

[Chalton_trc]

In online stores they say that it will be available on 10.01.2021. If they are fixing the problems now, will a final version be in stores by that date?

[Fungus]

That warning symbol probably isn’t a requirement by any safety standard. And I’m not suggesting Brymen is less safe or anything like that - I just noticed the BM786 LCD has a symbol for it - so perhaps Brymen has planes to implement it in the future.

Occam's razor says it's just a generic LCD.

[AVGresponding]

Again, during the last test where the DC had been removed, the meter was set to VFD.  The bargraph will be disabled, the filter will be active causing a bit of an voltage difference for the higher frequency content waveforms and yes, it only displays two places past the decimal point.  We can see this on page 24. 

Is it worth repeating this test with the VFD disabled?   I could also just run two meter and remove the DSO, maybe slow it down a bit further to make it easier to track.   We could also increase the number of waveforms.  This test requires little effort to setup so if you feel it's worth it, let me know. 

I am still not sure what the comment was about UNI-T not having a problem.  I could toss the 87V into the mix as well if this is what you want to see.  It just gets more difficult for me anyway, to follow what is going on with so many devices active at once.

Hi Joe,

If it is not big effort and you're willing to do it, sure, it would be nice.
It would be nice to see limits of this, and maybe with what waveforms it will happen. I doubt autoranging will have problem with standard waveforms...
Maybe see it through full range (6V, 60V, 600V) ... Definitely check whether it is VFD related.

...

There was a comment on YT that BM869s has a problem with 560kOhm resistance measurement if it is performed close to power cord.  I would propose to add this to the list of tests if you will decide to make next tests with BM786.

I can confirm that this is a thing. It starts at around 520k and persists up to 660k or so. It can be exacerbated by holding the meter in your hands.

I ran cables from a resistance decade to my meter, with a few cm being parallel to my PC power lead.

I was unable to duplicate the effect with my 87V, 289, or UT139C.

I'm guessing it's some kind of low hysteresis between the autorange selection between 600k and 6M, as it basically starts flipping between them at a rate of two or three Hz.