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How many cycles will the KeySight U1281A's detent spring last?

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Total Members Voted: 36

Author Topic: Handheld meter robustness testing  (Read 1149362 times)

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Online malagas_on_fire

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Re: Handheld meter electrical robustness testing.
« Reply #3200 on: March 23, 2019, 11:55:42 pm »
Can we put the pocket brymen on Mars ?

NASA provides some basic info on their tests, not standard of course, their own purposes. Funny thing  if pocket brymen would survive all NASA could throw out :D

https://www.nasa.gov/centers/johnson/pdf/639713main_Vibration_Testing_FTI.pdf
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Offline joeqsmithTopic starter

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Re: Handheld meter electrical robustness testing.
« Reply #3201 on: March 24, 2019, 01:17:29 am »
My first attempt to make a cheap table for testing meters, made from four small speakers.   A few problems I see with it is that the stroke is only about 3mm and the frequency response will be pretty limited.   

I did some testing with it to see how much force it could generate and it can easily lift the BM869s at DC.  As the frequency goes up, it looses a lot of travel.   

It appears others have been down this path....
https://pdfs.semanticscholar.org/ae56/0d0290985ec64fb901c3cdb5970c17d52514.pdf
« Last Edit: March 24, 2019, 01:41:33 am by joeqsmith »
 
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Online malagas_on_fire

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Re: Handheld meter electrical robustness testing.
« Reply #3202 on: March 24, 2019, 11:48:11 am »
About the NASA i was just joking.

That is the first search result on "floggle" for "vibration text fixture homemade". Super simple circuit and using and a new device such as the dongle USB joule thief mentioned as example and the more easy cheap MEMS  :P

In the paper for the MEMS they appear to put a plastic structure direct on the center hole. Does you're upper table is close enought to the subwoofers?
« Last Edit: March 24, 2019, 11:56:16 am by malagas_on_fire »
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Offline Fungus

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Re: Handheld meter electrical robustness testing.
« Reply #3203 on: March 24, 2019, 12:24:35 pm »
Be sure to put some screwdrivers in the box when you're shaking it.

 

Offline bd139

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Re: Handheld meter electrical robustness testing.
« Reply #3204 on: March 24, 2019, 12:41:34 pm »
Spotted in another thread:
A poor little Brymen being asked to check the EHT voltage in a Tek CRO.  :scared:


Only a couple of times its rated voltage.  :-DD
Recommended, NO. Impressive YES !

 :-DD :-DD :-DD   I continue to abuse the little pocket Brymen that member True posted about.  After everything I have done to this meter, it would be fun to take Dave's SANWA and have my own shoot out.   A badly abused Brymen vs a brand new Sanwa.   :box:

Original poster of the BM22s torture. It got up to around 2Kv then made some unpleasant noises, i assume the spark gaps going in it. I let it go for a few seconds. No measurement problems or damage afterwards I could identify.

Also indeed recommended no, but I didn't fancy putting the 87V near that one and the proper 40Kv probe was buried in the back of the junk cupboard somewhere. Seeing as I have five of these BM22's now (I get them free every time I buy something Rigol) I figured I'd see what it was capable of.

Incidentally no I wasn't in contact with the device while testing. That would be insane. I actually soldered the probe tips to the HT parts of the board and powered up remotely.

They are very handy little meters. I pop one in my pocket every time I go to a hamfest to test things before I buy.
 

Offline joeqsmithTopic starter

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Re: Handheld meter electrical robustness testing.
« Reply #3205 on: March 24, 2019, 04:19:08 pm »
Original poster of the BM22s torture. It got up to around 2Kv then made some unpleasant noises, i assume the spark gaps going in it. I let it go for a few seconds. No measurement problems or damage afterwards I could identify.

Also indeed recommended no, but I didn't fancy putting the 87V near that one and the proper 40Kv probe was buried in the back of the junk cupboard somewhere. Seeing as I have five of these BM22's now (I get them free every time I buy something Rigol) I figured I'd see what it was capable of.

Incidentally no I wasn't in contact with the device while testing. That would be insane. I actually soldered the probe tips to the HT parts of the board and powered up remotely.

They are very handy little meters. I pop one in my pocket every time I go to a hamfest to test things before I buy.

Wait, are you saying your afraid to use what I understand is the "gold standard" of meters because your concerned it will become damaged with something a cheap pocket meter can survive???  :-DD :-DD     

Silicone is dry enough to try some tests.   Shown running open loop.  The scope is showing the plate's position as it is swept from 10 to 300Hz.  Its far from flat. 

This paper talks about MIL-STD-810.  Figure 2 shows the displacement vs frequency for a helicopter.   

https://www.desolutions.com/blog/2017/05/mil-std-810-vibration-testing-category-24-minimum-integrity-tests-mit/

Offline bd139

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Re: Handheld meter electrical robustness testing.
« Reply #3206 on: March 24, 2019, 04:53:30 pm »
I think it’s more I’d cry if I blew up the 87V. If the BM22s blew up I’d throw it in the bin and get another one out  :-DD
 

Offline joeqsmithTopic starter

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Re: Handheld meter electrical robustness testing.
« Reply #3207 on: March 24, 2019, 09:22:00 pm »
I think it’s more I’d cry if I blew up the 87V. If the BM22s blew up I’d throw it in the bin and get another one out  :-DD
Your post is a testament to Brymen's robustness.     

I keep my first LeCroy DSO for that same reason.   When it comes to the handhelds, I have no problems abusing them for the benefit of others.   It's really their main purpose.  I had ran a long term high voltage test on the 87V to show the effects on the MOVs.   I didn't take it up to the same voltage level you have.       

https://youtu.be/dQPcAs0EEqY
 
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Offline Cliff Matthews

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Re: Handheld meter electrical robustness testing.
« Reply #3208 on: March 25, 2019, 12:03:09 am »
Joe, you'd give Dave recursive nightmares about spitting on contacts.. then again, he's a rock that probably sleeps like one  :-DD
 

Offline joeqsmithTopic starter

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Re: Handheld meter electrical robustness testing.
« Reply #3209 on: March 25, 2019, 02:24:31 am »
Joe, you'd give Dave recursive nightmares about spitting on contacts.. then again, he's a rock that probably sleeps like one  :-DD

I doubt it.  As Dave posted recently, we tend to deal in facts.  Show me some concrete data without yellow sticky notes with equations no one can make sense of and I may not run it..... No... I would still run it.   

Engineers are incredibly easy to shut up, they deal in facts, just show them concrete data and it's done.

If you don't have concrete data to show your device works and/or is practical, then it's not unexpected for people to call you things when you work in this sort of field. Because there are countless crackpots and tesla-nuts out there, the internet is filled with them, and many startup companies have stolen a lot of peoples money. People have good reasons to be very skeptical.

Offline joeqsmithTopic starter

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Re: Handheld meter electrical robustness testing.
« Reply #3210 on: March 25, 2019, 02:33:14 am »
I think it’s more I’d cry if I blew up the 87V. If the BM22s blew up I’d throw it in the bin and get another one out  :-DD
Your post is a testament to Brymen's robustness.     

I keep my first LeCroy DSO for that same reason.   When it comes to the handhelds, I have no problems abusing them for the benefit of others.   It's really their main purpose.  I had ran a long term high voltage test on the 87V to show the effects on the MOVs.   I didn't take it up to the same voltage level you have.       

https://youtu.be/dQPcAs0EEqY

Dang, rewatched that part and it looks like I had the 87V even higher than your Brymen for days.  That was a week long test!!  :-DD 

Online malagas_on_fire

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Re: Handheld meter electrical robustness testing.
« Reply #3211 on: March 25, 2019, 10:53:47 pm »
I think it’s more I’d cry if I blew up the 87V. If the BM22s blew up I’d throw it in the bin and get another one out  :-DD

Next time would be to put two meters in series  to increase impedance to measure HV.... and maybe you will double the problems :P Or get two new ones:


« Last Edit: March 25, 2019, 10:55:28 pm by malagas_on_fire »
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Offline bd139

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Re: Handheld meter electrical robustness testing.
« Reply #3212 on: March 25, 2019, 11:09:18 pm »
That's not a bad idea actually. Would probably work  :-DD

I've got 5 of them now. That's 50 meg and <10KV in theory ... hmmm  :scared:

(no I'm not going to do it - I found my 40KV probe now  :-DD)
 

Offline bd139

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Re: Handheld meter electrical robustness testing.
« Reply #3213 on: March 25, 2019, 11:14:15 pm »
I think it’s more I’d cry if I blew up the 87V. If the BM22s blew up I’d throw it in the bin and get another one out  :-DD
Your post is a testament to Brymen's robustness.     

I keep my first LeCroy DSO for that same reason.   When it comes to the handhelds, I have no problems abusing them for the benefit of others.   It's really their main purpose.  I had ran a long term high voltage test on the 87V to show the effects on the MOVs.   I didn't take it up to the same voltage level you have.       

Totally agree with the Brymen's robustness. I was honestly surprised. I've got a cheap DT830 floating around I will chuck across that HT divider next time and see what happens. That was a Farnell reject apparently. The display wasn't seated properly so it didn't work. I repaired it. Bet that'll blow up!

WRT the 87V, I tend to treat the HRC fuse, MOVs etc as "last resort". That's what will stop you getting toasted on a transient or a stupid error. For daily use I expect them to work ONCE to save my butt. That's worth a new meter. New me is not an option. I don't care if they survive or not.
 

Offline joeqsmithTopic starter

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Re: Handheld meter electrical robustness testing.
« Reply #3214 on: March 25, 2019, 11:41:53 pm »
WRT the 87V, I tend to treat the HRC fuse, MOVs etc as "last resort". That's what will stop you getting toasted on a transient or a stupid error. For daily use I expect them to work ONCE to save my butt. That's worth a new meter. New me is not an option. I don't care if they survive or not.

Oh, I get it.  Use cheap meters so the "gold standard" stays preserved as the shelf princess it is.   :-DD 

I doubt you will get enough energy from a CRO to blow up an 87V and kill you in the process.   On the 87V if it leaves the shelf, how would you ever know if it was stressed?  Buy a new one after each use?  Have a scope out and capture anything that happens to know what it was exposed to?  Send it to Fluke for some sort of annual inspection, MOV replacement? 

I never work on high energy circuits with my hobby so I have little concern something would ever blow up and kill me.   But I do have concerns that a meter would survive some basic transients.   Which is really the whole point of this long drawn out thread....

Offline bd139

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Re: Handheld meter electrical robustness testing.
« Reply #3215 on: March 25, 2019, 11:52:35 pm »
CRO for sure. The Fluke if stressed I’d expect to see functional failure somewhere.

I occasionally have to poke around on cat III three phase UPS / DC busbar installations at which point the 87V comes with me. This is mainly a blame establishing process at which point the “professional” electricians come in and we have grounds to disagree with them when they feed us a load of bollocks and an unrealistic quote  :-DD
 

Offline joeqsmithTopic starter

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Re: Handheld meter electrical robustness testing.
« Reply #3216 on: March 26, 2019, 12:45:06 am »
Yea, I know what that's like.  I've had to venture into the world of CAT III now and then.  When it comes up, something is going on and I will need something more than a basic meter so I take that HIOKI with me.   I'm not an electrician but have some idea what I am doing, and I use clamps so fairly low risk.  Also, the voltages/currents are fairly low.  The first person I want to talk to is their master electrician.   I've had some pretty insightful conversations with a few of them,  especially if I keep them in the loop while I am working.     

I had HIOKI come in and demo the first meter I started using.  They left it with me to try out.  We surge tested it for real, not these little transients that I show in my home videos.   They come at a price but I do like their products.  Then again, I tried to contact them from my home email account and could never get them to respond. 

 
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Offline joeqsmithTopic starter

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Re: Handheld meter electrical robustness testing.
« Reply #3217 on: March 26, 2019, 02:14:05 am »

Offline Cliff Matthews

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Re: Handheld meter electrical robustness testing.
« Reply #3218 on: March 26, 2019, 03:07:04 am »
I used to work for a company that had a magnesium table for vibration testing. I guess that's gotta be the duck's gut's for stress, but how do you plan to integrate this into your already detailed scope of tests?
 

Offline EEVblog

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Re: Handheld meter electrical robustness testing.
« Reply #3219 on: March 26, 2019, 03:43:29 am »
In the past, I have had to test some of my designs for vibration.  These were typically larger/heavier than a handheld meter and I would suggest a more harsh environment than a typical meter would ever see.   I am thinking I may try to come up with some sort of simple test jig to run a few meters on and may start with this little pocket meter.    I suspect mostly they see the drop or maybe low frequency low displacement.  I have not found any standards yet that companies have followed.   

There are vibration standards for both ground (truck/rail) and air transport (the transportation of the product is a necessity and known quantity, unlike end-user requirements). I used to test gear against this with custom jigs, but it was a long time ago so don't recall the standards off-hand.
« Last Edit: March 26, 2019, 03:45:13 am by EEVblog »
 

Offline Cliff Matthews

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Re: Handheld meter electrical robustness testing.
« Reply #3220 on: March 26, 2019, 03:57:42 am »
In the past, I have had to test some of my designs for vibration.  These were typically larger/heavier than a handheld meter and I would suggest a more harsh environment than a typical meter would ever see.   I am thinking I may try to come up with some sort of simple test jig to run a few meters on and may start with this little pocket meter.    I suspect mostly they see the drop or maybe low frequency low displacement.  I have not found any standards yet that companies have followed.   

There are vibration standards for both ground (truck/rail) and air transport (the transportation of the product is a necessity and known quantity, unlike end-user requirements). I used to test gear against this with custom jigs, but it was a long time ago so don't recall the standards off-hand.
Some of those standard's may be listed in the PDF here: http://www.sci-lab.com/2743-01.pdf
« Last Edit: March 26, 2019, 02:02:44 pm by Cliff Matthews »
 

Offline joeqsmithTopic starter

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Re: Handheld meter electrical robustness testing.
« Reply #3221 on: March 26, 2019, 12:02:09 pm »
I used to work for a company that had a magnesium table for vibration testing. I guess that's gotta be the duck's gut's for stress, but how do you plan to integrate this into your already detailed scope of tests?
We had similar tables, some that were the floor of the environmental chambers.  It's a bit overkill for the home lab.   :-DD

Like my transient and life cycle testing, I will most likely try a couple of meters and see how they behave.  Basically look for some resonate points to get some idea on the frequency range and displacement.  Once I have something that is close to what I am looking for,  make a video and see what sort of feedback I get. I need to come up with some generic way to secure the various meters in 3 axis before I can try it.  Also, I am just starting to look at how to control it.     

The weight of the meters and sound level will limit what I can do with this setup.   The switch life cycle tests are pretty bad when you have a meter like the Fluke 87V gold standard that starts to grind.  No one wants to listen to that for days on end.  This would be much worse. 

There are some meters I'm a bit concerned with.   The 121GW has the unsupported card holder that I can see cracking pretty easily for example.   A lot of meters will lay fairly large alumelec on the board without support.   Some meters I have used the old stand up TH designs. 

Offline rsjsouza

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Re: Handheld meter electrical robustness testing.
« Reply #3222 on: March 26, 2019, 12:30:53 pm »
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.
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Offline mqsaharan

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Re: Handheld meter electrical robustness testing.
« Reply #3223 on: March 26, 2019, 06:32:05 pm »
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 joeqsmithTopic starter

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Re: Handheld meter electrical robustness testing.
« Reply #3224 on: March 27, 2019, 02:49:21 am »
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


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