[volt-nuts] Guidance requested.

David C. Partridge david.partridge at perdrix.co.uk
Sun Jul 9 17:01:41 EDT 2017

So I have:

 1) A Datron 4808 (not calibrated recently AFAIK, and no way to check),
 2) A 3458A which is about 6 months out of calibration (sadly not by
 3) Three 7081s two of which are also 6 months out of calibration against
the 3458A,
 4) A 720A.

The readings of the output of the Datron for the 1V, and 10V, 100V and 100V
ranges on the 3458A (NPLC100) are:

 1.00000177V (high limit 1.00000480V),
 9.9999964V (low limit 9.9999720V,
 99.999380V and climbing slowly (low limit 99.999550V)  In spec some five or
so minutes later.
 999.98xxxV (and falling) (low limit 99.99450V) So definitely out of spec

To be fair both the 4808 and 3458A have only been on for about 8 hours -
things may improve :).
The two "recently out of calibration" 7081s disagree with the 3458A but I've
not made a record of their readings (a job for tomorrow).  The other 7081 is
not in consideration at present as its of unknown provenance.

I also have out of calibration Cropico VS10 and Fluke 732A.

I'm going to run the 720A through its self-calibration tomorrow.

I can't begin to afford to send the 4808 to Fluke or the 3458A to Keysight
for calibration.   Even local cal. labs are a bit pricey, and I'm not over
sure I trust them to get this sort of equipment correctly calibrated, given
that they normally only handle PAT testers, 3.5 or 4.5 digit DMMs, and maybe
the odd 6.5 digit meter.

So please how best to proceed from here?


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