Handheld meter robustness testing

[TheAmmoniacal]

Give us an unboxing!

[Hydrawerk]

I am looking forward to Dave's DMM. Who manufactured it?

[TheAmmoniacal]

I am looking forward to Dave's DMM. Who manufactured it?

You can start reading from here: https://www.eevblog.com/forum/chat/new-eevblog-branded-multimeter-coming/msg1220835/#msg1220835

[joeqsmith]

I have been playing around with the pre-released 121GW and am working with Dave to get an idea on how he would like to proceed.    Because the meter is still being developed it makes things a little more difficult.  So please be patient while we sort things out.   

I will come out and say the meter is pretty cool and has a lot more features than my foam replicas!   

[bitseeker]

No worries, Joe. Looking forward to however much you can accomplish pre-release, and more after release.

[Vgkid]

Are you going to do a review before Dave does?
Or blow it up before it gets released...

[joeqsmith]

Because the meter is not release and still being developed, I am unable to do a detailed review.  Dave has suggested the we basically run the tests on it and see how it does.  The problem with this is I need to do some sort of functional test to know if the meter has changed after testing.  So some sort of mini-review is in order if anything just to show that the meter basically works.   

I am thinking we would put it through all the same tests I normally keep metrics on.   It would give Dave some idea how the meter will stack up against the others I have looked at. 

Yes, it could very well get damaged before it gets released.  That's the nature of running the tests. 

Because that grill starter has damaged so many UNI-Ts, I plan to run it before using the large gun.  This assumes it has survived the AC line test. 

Just one transient off the grill starter took out the UNI-T UT181A because of a poor layout, where the EEVBLOG rebranded Brymen BM235 has been unstoppable and recently was exposed to a 12KV transient.   Where does the 121GW fit?

[Crumble]

LOL! I love it how you have the grillstarter sitting ready to ignite. I'd just note this unit on your spreadsheet as "121GW prototype" so no one will complain if their unit turns out to behave differently. To me it seems quite obvious some kind of functional test is needed, so maybe Dave can comment on functionality he thinks is undesirable to review (en therefore test). I don't think Dave will be particularly obstructive in this respect. 

[joeqsmith]

LOL! I love it how you have the grillstarter sitting ready to ignite. I'd just note this unit on your spreadsheet as "121GW prototype" so no one will complain if their unit turns out to behave differently. To me it seems quite obvious some kind of functional test is needed, so maybe Dave can comment on functionality he thinks is undesirable to review (en therefore test). I don't think Dave will be particularly obstructive in this respect. 

I think after showing the output of the grill starter and how it compares with the IEC standard, and yet damaging so many UNI-T meters, people will want to see if it will damage the 121GW. 

Yes, this pre-production meter will need to be clearly marked in the spreadsheet.   

[Fungus]

I think after showing the output of the grill starter and how it compares with the IEC standard, and yet damaging so many UNI-T meters, people will want to see if it will damage the 121GW. 

I definitely do.

I'm not holding my breath though. I suspect it'll survive.

[Fungus]

Mr. JQS:

Is it possible/practical/insane to incorporate a real world 'carpet surf' Pass or Fail in your meter testing procedures? 

or fast removal of a pullover garment that charges up ?

Not really practical. It depends too much on the weather, etc.

[joeqsmith]

Mr. JQS:

Is it possible/practical/insane to incorporate a real world 'carpet surf' Pass or Fail in your meter testing procedures? 

or fast removal of a pullover garment that charges up ?

Not really practical. It depends too much on the weather, etc.

Agree.  Then again, drop testing a meter on the desk also has it's share of variables but I gave it a go just for you.   

When I was attempting to design my own gun from scratch (not for the faint of heart) I showed a transient when I just sat down in my chair without a strap.   

[Fungus]

Not really practical. It depends too much on the weather, etc.

Agree.  Then again, drop testing a meter on the desk also has it's share of variables but I gave it a go just for you.   

But it's reasonably repeatable. 

You didn't do the screwdriver test though. I thought something like a large screwdriver handle on the table could concentrate the force and give it something to spin/bounce off.

Maybe we need a robot arm to hurl meters against walls.

[joeqsmith]

I was waiting for you to write a detailed test plan. 

[3db]

I think it would be good if you included the  'Mrs Smiths Fabric Test' in all future meter tests.
It can be the new electrostatic reference source. 

3DB

[joeqsmith]

I think it would be good if you included the  'Mrs Smiths Fabric Test' in all future meter tests.
It can be the new electrostatic reference source. 

3DB

That may not be a bad idea.  The reason it came up with the Gossen was I had just never seen a meter that would wander that bad with the inputs shorted. 

[Fungus]

I was waiting for you to write a detailed test plan.

It would help to know the orientation of the moving parts inside the relay.

[joeqsmith]

Now you know that's not a detailed set of test requirements. 

[MacMeter]

Now you know that's not a detailed set of test requirements.

It's for those with SLIPPERY hands. Can't remember the last time I dropped my meter on a screwdriver, oh wait, now I remember, I've never dropped one, at all.

[Monkeh]

Now you know that's not a detailed set of test requirements.

It's for those with SLIPPERY hands. Can't remember the last time I dropped my meter on a screwdriver, oh wait, now I remember, I've never dropped one, at all.

I've very nearly dropped a meter into a cow pat. Wouldn't be much of an impact, but it'd definitely affect the measurements!

[Crumble]

Now you know that's not a detailed set of test requirements.

It's for those with SLIPPERY hands. Can't remember the last time I dropped my meter on a screwdriver, oh wait, now I remember, I've never dropped one, at all.

I've very nearly dropped a meter into a cow pat. Wouldn't be much of an impact, but it'd definitely affect the measurements!

What were you measuring? 

[...]
It's for those with SLIPPERY hands. Can't remember the last time I dropped my meter on a screwdriver, oh wait, now I remember, I've never dropped one, at all.

Yeah, but it still does happen. I think it is a fair requirement for a handheld meter to be able to survive falling without changing cal by ~30x as this one did. I can imagine the situations in which it is most important the value is correct (like when measuring the presence of mains) it is most likely the meter will fall (like when doing building activities or installation work). I can't remember when I last dropped a multimeter, but I don't do the aforementioned things.

[Monkeh]

Now you know that's not a detailed set of test requirements.

It's for those with SLIPPERY hands. Can't remember the last time I dropped my meter on a screwdriver, oh wait, now I remember, I've never dropped one, at all.

I've very nearly dropped a meter into a cow pat. Wouldn't be much of an impact, but it'd definitely affect the measurements!

What were you measuring? 

I was working on a horse lorry. Farms are dirty places y'know. I believe at the time I was trying to get the ******* to start.

[joeqsmith]

Now you know that's not a detailed set of test requirements.

It's for those with SLIPPERY hands. Can't remember the last time I dropped my meter on a screwdriver, oh wait, now I remember, I've never dropped one, at all.

I've very nearly dropped a meter into a cow pat. Wouldn't be much of an impact, but it'd definitely affect the measurements!

What were you measuring? 

[...]
It's for those with SLIPPERY hands. Can't remember the last time I dropped my meter on a screwdriver, oh wait, now I remember, I've never dropped one, at all.

Yeah, but it still does happen. I think it is a fair requirement for a handheld meter to be able to survive falling without changing cal by ~30x as this one did. I can imagine the situations in which it is most important the value is correct (like when measuring the presence of mains) it is most likely the meter will fall (like when doing building activities or installation work). I can't remember when I last dropped a multimeter, but I don't do the aforementioned things.

You saw a meter change 30X after being dropped?   

[joeqsmith]

Seriously guys, you can calibrate the -carpet surf-  test jig by walking (or 'surfing') across a fixed length of carpet with same slippers or shoes,
both selected to create a suitable electrostatic BANG! to a multimeter.

The brief ON and OFF pullover test can be done in any weather,
I don't expect Mr JQS to keep on a pullover for the duration of a Youtube video during inferno weather conditions

This can be the final word on real world  "Handheld meter electrical robustness testing."  for any meter! 

Assuming it first survives the screwdriver drop and cow pat test               (Fluke 28-11 owners will love that s***)   

As Fungus mentioned and if you read the couple of papers I had linked in the YT comments, the type of fabric will have a big effect.  So will humidity.  Your test plan is right there with Fungus's drop test.  I think if you do a little research on how the ESD standards evolved (continue to evolve) you may find it interesting. 


Well, it's been another VERY long day of meter testing.  Let me just say from my perspective of running these test, it's one thing to buy a meter that is in production that anyone can buy and then run these potentially destructive tests on it.  Running a meter that you know there are only a very limited number made is a whole different story. If it were my design, I would be all for running it to failure.  I've been in that position many times.   

The video is currently rendering.  Because of the meter not being released yet, my plan is to allow Dave to review it first and make sure there is nothing proprietary being shown.   I've kept things pretty basic and not expecting there to be problems.   So stay tuned, it shouldn't be much longer.   

[joeqsmith]

The video is in Dave's hands now. 

The house was pretty warm today and that LeCroy DSO makes for a small space heater.  I decided to put one of the battery powered Flukes to work.  As beat up as these were, so far they seem to be working fine.  This one needs a new EL after seeing how bright the other one was after replacing it.