Poll

Are you interested in seeing more handheld meters tested?

This testing is pointless! Please STOP damaging these meters!
3 (6.4%)
 Yes, I would like to more meters tested.
44 (93.6%)

Total Members Voted: 47

Author Topic: Handheld meter electrical robustness testing.  (Read 503012 times)

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Offline mqsaharan

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Re: Handheld meter electrical robustness testing.
« Reply #3225 on: March 27, 2019, 05:32:05 am »
For those vivration tests, I would love to see how Fluke tests a meter such as the 28 II EX - I heard it is potted inside.

It will of course be very interesting to see vibration tests on different multimeters and especially Flukes. Because they have removed the "Vibration" and "Shock" heads from the specifications of their multimeters in current revisions. Either they feel no more confident or the requirements have gone more stringent.

28 II Ex is partially potted. You can take a look at it in the following video from MJLorton, about 13:10 minutes in where he does a teardown.


 
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Offline joeqsmith

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Re: Handheld meter electrical robustness testing.
« Reply #3226 on: March 27, 2019, 01:49:21 pm »
First attempt to run the table closed loop.   The top graph is showing the displacement in mm vs frequency in Hz.  The control signal was set to 1mm.   The lower graph, green trace is showing the integral term.  The vertical scale is in volts.  The Arb is driving the power amplifier.  A LVDS is used to sense the table's position.   At 37Hz, it was starting to roll off.  It was also getting a bit too loud which is why I aborted the test.      The sweep time was fairly short and the tune was a swag.   

I can see the posts now, "I've owned that meter for 10 years and its never had a problem. "    :-DD :-DD
How electrically robust is your meter?? https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 

Online rsjsouza

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Re: Handheld meter electrical robustness testing.
« Reply #3227 on: March 28, 2019, 08:24:36 am »
I can see the posts now, "I've owned that meter for 10 years and its never had a problem. "    :-DD :-DD
Yes, I think this is a great exercise but, differently than your rotary test or even the transients, it is much harder to translate a constant vibration pattern to a real world scenario. A constant vibration table seems closer to leaving the meter on top of a car's engine or the washing machine in a cycle spin, but it can barely translate to the G forces subjected by falls, for example.

However, we do what we got to do.
Vbe - vídeo blog eletrônico http://videos.vbeletronico.com

Oh, the "whys" of the datasheets... The information is there not to be an axiomatic truth, but instead each speck of data must be slowly inhaled while carefully performing a deep search inside oneself to find the true metaphysical sense...
 

Offline joeqsmith

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Re: Handheld meter electrical robustness testing.
« Reply #3228 on: March 28, 2019, 10:48:26 am »
I can see the posts now, "I've owned that meter for 10 years and its never had a problem. "    :-DD :-DD
Yes, I think this is a great exercise but, differently than your rotary test or even the transients, it is much harder to translate a constant vibration pattern to a real world scenario. A constant vibration table seems closer to leaving the meter on top of a car's engine or the washing machine in a cycle spin, but it can barely translate to the G forces subjected by falls, for example.

However, we do what we got to do.

I don't see it being any different than other tests I have ran.   I don't try to come up with real world scenarios but rather some standard way that they can be evaluated to compare their performance.    I could for example find some obscure circuit that was once use that causes some transient that may damage a meter.   If I adopt that as my standard, I can only tell what meters survive it.  Not how much more they could take or how close the ones were that failed.   The rotary switch life test is similar.  I keep track of the contact resistance to get an idea of how the meters perform while they are being cycled.   One way would be to take the meter apart during the test and spit shine the contacts to see how they are wearing.   

I would like to weed out the better class of meters, just like I have done with every other test.    In this case, I could have different profiles.  That's a ways out.   
How electrically robust is your meter?? https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 

Offline malagas_on_fire

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Re: Handheld meter electrical robustness testing.
« Reply #3229 on: March 28, 2019, 11:01:40 am »

I can see the posts now, "I've owned that meter for 10 years and its never had a problem. "    :-DD :-DD


I have a uni-t for 50b for 10 years and had problems like burn 500mA fuses, almost neutralized the Amps shunt while poking UPS outlet ( saved by RCD), original leads are out. Vibration is a good exercice for comparisson between meters whether they keep the measures stable during that kind of stress or some maybe component snaps out of the PCB :P

 But only takes some water to turn years into seconds,

If one can make knowledge flow than it will go from negative to positve , for real
 

Offline joeqsmith

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Re: Handheld meter electrical robustness testing.
« Reply #3230 on: March 28, 2019, 01:50:17 pm »
I doubt I would try and power them up during the test and take any readings.  While I can believe that with some of the meters, the adjustment pots could move.  The bigger problem is that some meters, like the 121GW for example, are sensitive to changing magnetic fields.   It's early and I may change my view of this.  I can see doing some sort of before and after test for meters along with pulling it apart for inspection.
How electrically robust is your meter?? https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 

Offline joeqsmith

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Re: Handheld meter electrical robustness testing.
« Reply #3231 on: March 29, 2019, 10:41:19 am »
It will of course be very interesting to see vibration tests on different multimeters and especially Flukes. Because they have removed the "Vibration" and "Shock" heads from the specifications of their multimeters in current revisions. Either they feel no more confident or the requirements have gone more stringent.
From the Fluke 189 manual:
Per MIL-T-PRF 28800 for Class II instruments

Looking at the standard for a Class 2,  for the sinusoidal profile they sweep from 5 - 55Hz and 1.5mm down to 0.5mm.  This may be doable with the home made table.   This document is available for free on-line. 
How electrically robust is your meter?? https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 

Offline Cliff Matthews

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Re: Handheld meter electrical robustness testing.
« Reply #3232 on: March 29, 2019, 10:53:57 am »
Is this what the doctor ordered? Maybe it's not the most recent perhaps..
http://everyspec.com/MIL-SPECS/MIL-SPECS-MIL-T/download.php?spec=MIL-T-28800E.030735.pdf
 

Offline joeqsmith

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Re: Handheld meter electrical robustness testing.
« Reply #3233 on: March 29, 2019, 11:34:26 am »
I was looking at the MIL-PRF-28800F which superseded T.   It's also available on everyspec.com.   See Table 4 attached.

Once the glue sets up for the fixture, I can see how close it will track that profile. 

Link to the full spec if interested
http://everyspec.com/MIL-PRF/MIL-PRF-010000-29999/MIL-PRF-28800F_18207/
« Last Edit: March 29, 2019, 11:39:03 am by joeqsmith »
How electrically robust is your meter?? https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 
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Offline joeqsmith

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Re: Handheld meter electrical robustness testing.
« Reply #3234 on: March 30, 2019, 04:49:23 am »
Making the round trip from 5 to 55Hz.   
How electrically robust is your meter?? https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 

Offline malagas_on_fire

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Re: Handheld meter electrical robustness testing.
« Reply #3235 on: March 30, 2019, 07:09:38 am »
The frequency follows quite well the table attached in the previous post and displacement results "touché" . It is required to do a pause between frequency ranges while testing?
If one can make knowledge flow than it will go from negative to positve , for real
 

Offline joeqsmith

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Re: Handheld meter electrical robustness testing.
« Reply #3236 on: March 30, 2019, 07:58:15 am »
It is required to do a pause between frequency ranges while testing?
Like the transient testing, I am loosely using the standards as a guide.   I provided a link to the standard if you would like to read it.  I suggest section 4.5.5.3.2.   At this time, I plan to run a linear sweep that follows that profile.  Maybe run 3 cycles, up and down, half hour per cycle.   I have no plans to search for resonance.   I'll just let it run and do a before and after functional test and inspection.     I am also thinking to just run it in the one axis, backside down, rather than to look at all three.   It's all up in the air for now until I actually try running a few meters. 
How electrically robust is your meter?? https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 
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Offline joeqsmith

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Re: Handheld meter electrical robustness testing.
« Reply #3237 on: March 31, 2019, 02:51:49 am »
Time for a test drive...
How electrically robust is your meter?? https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 
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Offline malagas_on_fire

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Re: Handheld meter electrical robustness testing.
« Reply #3238 on: March 31, 2019, 03:14:36 am »
Thanks for the info related to the standard and the go to.  Hope the needle of  that Multimeter survives :P
« Last Edit: March 31, 2019, 03:16:48 am by malagas_on_fire »
If one can make knowledge flow than it will go from negative to positve , for real
 

Offline malagas_on_fire

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Re: Handheld meter electrical robustness testing.
« Reply #3239 on: March 31, 2019, 03:21:41 am »
Meanwhile check out the Vbe's supposed aneng basher ,  Mestek DM91A:

https://youtu.be/XojTrnXq_LU

looks better built and uses more common fuses, ,maybe 5x20mm not tiny .
If one can make knowledge flow than it will go from negative to positve , for real
 
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Offline joeqsmith

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Re: Handheld meter electrical robustness testing.
« Reply #3240 on: March 31, 2019, 03:27:59 am »
Thanks for the info related to the standard and the go to.  Hope the needle of  that Multimeter survives :P
It was a fairly inexpensive meter and has a bit of weight to it compared with the pocket meter.   

I'm not sure which axis would be the worse for this particular meter but I am thinking to run them as shown. 

***
Watched his last video.  Would have liked to have seen the PCB removed so we could see the switch contacts.   I suspect it just uses the single PTC and some transistors for the clamp.  Maybe a TVS in there.  I doubt it would do very well in my transient testing.   
« Last Edit: March 31, 2019, 03:48:20 am by joeqsmith »
How electrically robust is your meter?? https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 

Offline joeqsmith

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Re: Handheld meter electrical robustness testing.
« Reply #3241 on: March 31, 2019, 04:42:20 am »
On my bike, I have a mechanical pressure gauge which is filled with glycerine to dampen the pulses and vibrations.  Maybe the high end analog meters had some sort of dampeners but this meter doesn't and had a few resonate frequencies.   Poor meter....

https://youtu.be/45LaMWZ9en4
How electrically robust is your meter?? https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 
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Offline Cliff Matthews

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Re: Handheld meter electrical robustness testing.
« Reply #3242 on: March 31, 2019, 05:36:25 am »
So I take it we could never count on this meter at the Baja 1000?  :-DD
 

Offline malagas_on_fire

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Re: Handheld meter electrical robustness testing.
« Reply #3243 on: March 31, 2019, 06:08:23 am »
Wow looks like the needle is having a bad day ilke offroad indeed , What about inside ? Any loosy components?
If one can make knowledge flow than it will go from negative to positve , for real
 

Offline joeqsmith

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Re: Handheld meter electrical robustness testing.
« Reply #3244 on: March 31, 2019, 06:33:58 am »
Low frequency (no resonance), vertical mount, shot at 1000fps.   Ride em cowboy... 

https://youtu.be/WCIpm8peQSU
How electrically robust is your meter?? https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 
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Offline joeqsmith

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Re: Handheld meter electrical robustness testing.
« Reply #3245 on: March 31, 2019, 07:50:09 am »
The mechanical meter did not hold up very well.  Note the adjustment set to both extremes.   One of the batteries had leaked and the vibration caused the solution to spray all over inside the meter.   What a mess... 
How electrically robust is your meter?? https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 

Offline Towger

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Re: Handheld meter electrical robustness testing.
« Reply #3246 on: March 31, 2019, 08:02:26 am »
Looks like you have discovered a new technique for accelerated battery ageing testing. 
 

Online bd139

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Re: Handheld meter electrical robustness testing.
« Reply #3247 on: March 31, 2019, 08:16:05 am »
This reminds me of the first meter I blew up. A Micronta 212. I might buy one off ebay if I see one cheap to see if I can recreate that moment on video. The entire meter front filled up with smoke and the needle fell off after leaving it on the 15V DC range and poking a 300V AC HT secondary on a valve radio transformer.  :-DD
 

Offline Cliff Matthews

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Re: Handheld meter electrical robustness testing.
« Reply #3248 on: March 31, 2019, 08:54:43 am »
This reminds me of the first meter I blew up. A Micronta 212. I might buy one off ebay if I see one cheap to see if I can recreate that moment on video. The entire meter front filled up with smoke and the needle fell off after leaving it on the 15V DC range and poking a 300V AC HT secondary on a valve radio transformer.  :-DD
This could be the victim.. >:D https://www.ebay.co.uk/itm/Radio-Shack-Micronta-22-212-multimeter-works/123706889646
 

Online bd139

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Re: Handheld meter electrical robustness testing.
« Reply #3249 on: March 31, 2019, 08:57:24 am »
I think I'd probably put 10GBP to it. That is coming up at 28 GBP. Some idiot is selling one here for 49.99 GBP as well which is a joke! It's that bad at 2k/volt it's worth nothing!
 


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