I am mostly curious if the standard omits the transient tests for inputs like ohms
as a way to explain how a high end meter like the keysight could pass third party testing, but still fail at your less demanding tests.
I am mostly curious if the standard omits the transient tests for inputs like ohms
I believe it specifically includes them, that meters have to "fail safely" with all possible combinations of selector switch and input jack.
as a way to explain how a high end meter like the keysight could pass third party testing, but still fail at your less demanding tests.
CAT rating is a safety rating. If the user was in no danger then it's a pass!*
Is there a hard requirement in the standard to indicate unsafe voltages or is is the requirement something more like "never show lower voltages than are actually present"? A blank screen would meet that requirement - if it's not showing you any voltages at all then it's not telling you any lies.
(*) I'm not an expert, I haven't read the standard, this is just my understanding from reading Internet forums. I love being corrected.
CAT rating is a safety rating. If the user was in no danger then it's a pass!*Again, how do you know that the user would not be in danger? How do you know that the meter would not fail catastrophically if there was sufficient energy behind the pulse?
I would NOT be comfortable using a meter that can breakdown internally at half its rating if I were working in an arc flash environment.
Again, are you really able to extrapolate safety from Joe's tests?
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All we know from Joe's testing is that an ESD event with a 5KV or greater potential can irreparably damage the meter.
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That's why I am curious about how the standards are worded, and I thought you had a copy (I do not have access to a copy) which is why I asked you how it is worded.
I would NOT be comfortable using a meter that can breakdown internally at half its rating if I were working in an arc flash environment.So thank joe for making this video and don't buy a Keysight.
Mismatches of inputs and ranges are examples of REASONABLY FORESEEABLE MISUSE, even if the documentation or markings prohibit such mismatch.
QuoteMismatches of inputs and ranges are examples of REASONABLY FORESEEABLE MISUSE, even if the documentation or markings prohibit such mismatch.
The attached image was taken shortly after design an construction of the transient generator (2016). Shown with 5kV peak, 100us FWHH, no load. This is the transient that damaged both Keysight meters.
Just out of curiosity, have you looked at the waveform of the grill starter output, across a nominal load of say 10MΩ, to simulate what it would look like to the front end of a typical handheld DMM?
10MΩ should get you in the ball-park though? Maybe with some MOVs or GDTs in parallel...
My understanding is these piezo ignitors don't pack much of a punch, energy wise, but can deliver maybe 10kV or so, happy to be corrected if wrong.
But now I think we get to the crooks of what you are driving at.
............ the crooks of what you are driving at. You suspect the grill start is putting out ...
A megavolt? Not hardly. That would allow for a spark across a gap of a metre, never mind a meter!
You suspect the grill start is putting out 1MegaVolt which unfairly wipes out all of those UNI-T meters.
As I said, maybe 10kV.
If we use 1000V per mm, 10mm air gap for 10kV, I have no doubt that I have one grill starter that will exceed that.
What I was curious about is whether the the output of these things is too fast for the protection circuitry to react to, as it is obviously going to be way lower energy than the IEC standard tests for CAT ratings, and less than the 20J your transient generator puts out. My point therefore is, given these facts, how does it damage (for example Uni-T) meters? My only guess is it's too fast for the clamp(s).[/color][/size][/b]
I am not confused, I never mentioned ESD, that was Fungus and latterly yourself. I am asking a question. What does the transient generated by a grill starter look like across the inputs of a DMM?
You partially answered me by pointing out that piezo spark generators are very inconsistent in their output; fine, thank you for that information.
I then asked why the grill starter damages meters; is the transient too fast for the clamp, or is it something else? I mentioned CAT ratings and your transient generator merely to compare the energy levels involved.
I am asking for your considered opinion, or if you know the answer, that is all. I am not asking you to perform any additional tests.
What does the transient generated by a grill starter look like across the inputs of a DMM?
Life cycle testing has begun. How many cycles do you think the detent spring will last? Cast your vote...