Calibration Fail on test current

[andy dubvan]

Hi all
My Fluke tester failed on one test today while having it's annual calibration, the continuity resistance test current.
Test Current - applied Value 205.0mA
Measured Value 218.0mA
Specification+- 10mA

So a fail from the calibration company because it was 13mA. However I read ( on Line ) that for continuity testing there must be a minimum current of 200mA but I am struggling to find that statement in the books, could someone point me to the info please
Thanks
Andy

 

[Moley]

Unless I'm miss understanding what you wrote the applied current was over 200mA, it was 205mA. The max reading your meter should have given is 205mA +- 10mA, so max 215mA. The reading you meter gave was 218mA which is out of the permitted tolerance.

 

[westward10]

GN3, Section 4.3

 

[andy dubvan]

Unless I'm miss understanding what you wrote the applied current was over 200mA, it was 205mA. The max reading your meter should have given is 205mA +- 10mA, so max 215mA. The reading you meter gave was 218mA which is out of the permitted tolerance.

Hi Moley, I believe the pass tolerance for the calibration test is 10mA so yes mine failed by giving a higher reading, but the min test voltage as as stated in GN3 is 200mA so mine being over should be ok....should it not ?

 

[andy dubvan]

GN3, Section 4.3

yep got it, thankyou

 

[Moley]

No, it's still out of tolerance. If the applied current was 205mA and the tolerance is +-10mA the maximum reading should be 215mA.

 

[andy dubvan]

No, it's still out of tolerance. If the applied current was 205mA and the tolerance is +-10mA the maximum reading should be 215mA.

Hey, yes I agree it is out of tolerance on that specific test, according to the calibration company the tolerance is +- 10mA and on the calibration test results for that specific test it says FAIL, but in GN3 it states that the min test voltage is 200mA, the fluke complies with that as it is putting a test voltage of 218mA.
So to me as the tester passed all the other tests it's still good to use ?

 

[davesparks]

Hey, yes I agree it is out of tolerance on that specific test, according to the calibration company the tolerance is +- 10mA and on the calibration test results for that specific test it says FAIL, but in GN3 it states that the min test voltage is 200mA, the fluke complies with that as it is putting a test voltage of 218mA.
So to me as the tester passed all the other tests it's still good to use ?

It is not putting out a test voltage of 218mA it is a test current.

As you have already said the tolerance is +/-10mA and the nominal current should be 200mA, so with that tolerance the maximum allowable current would be 210mA. 218mA is higher than 210mA so it is a fail as it is out of tolerance.

 

[andy dubvan]

It is not putting out a test voltage of 218mA it is a test current.

As you have already said the tolerance is +/-10mA and the nominal current should be 200mA, so with that tolerance the maximum allowable current would be 210mA. 218mA is higher than 210mA so it is a fail as it is out of tolerance.

Yeah wrong choice of word, should have been current not voltage
I'm not disputing whether it is out of tolerance for that specific test. I agree it is ( for that specific test ).
I was looking for the statement that says a min test current etc which i've now got ( GN3 )

I suppose the question is now, is the tester still good to use, as the only fail in the calibration was the test current, but that still complies with GN3.

 

[Moley]

It may comply with GN3 by being over 200mA but it's still out of calibration. The unit isn't within the specified tolerances. Let's say the test current was 5A and not 200mA. It's still over the 200mA but is it within tolerance?

 

[davesparks]

I was looking for the statement that says a min test current etc which i've now got ( GN3 )

GN3 is not relevant, it tells you what type of test should be used, it does not set the specification that a particular tester should be calibrated against.

The calibration limits are either in accordance with the manufacturer's specification or British, European or international standards.

I suppose the question is now, is the tester still good to use, as the only fail in the calibration was the test current, but that still complies with GN3.

No, it has failed calibration, it needs to be repaired.

 

[andy dubvan]

GN3 is not relevant, it tells you what type of test should be used, it does not set the specification that a particular tester should be calibrated against.

The calibration limits are either in accordance with the manufacturer's specification or British, European or international standards.


No, it has failed calibration, it needs to be repaired.

My fluke is quite old these days, spoke to fluke earlier today and they suggested because of it's age spares may be a problem and it could be that I get it repaired and other things may start to fail. So I may just have to bite the bullet and buy a new tester .

Thanks for the input everyone

 

[davesparks]

My fluke is quite old these days, spoke to fluke earlier today and they suggested because of it's age spares may be a problem and it could be that I get it repaired and other things may start to fail. So I may just have to bite the bullet and buy a new tester .

Thanks for the input everyone

I'd speak to an independant company about fixing this, you'd expect it to be a relatively simple adjustment and not require much in the way of spare parts.