[volt-nuts] A Fluke 732A

[Charles Steinmetz]

Thomas wrote:

>If I send a 732A to Fluke and have it calibrated, and you stop by 
>with yours shortly after mine returns, has a day or so to settle, 
>and appear correct with my 3458A, you could then calibrate your 732A 
>using of mine and feel fairly confident you standard is also a few 
>PPM from 10 volts. Now lets stay you repeat this with another 
>Volt-Nut when his standard returns. You do not have documents 
>proving the accuracy of your standard because none of the standards 
>used are parts of a accredited lab,

Documentation and accreditation are two entirely different 
things.  In this case, the documentation would be the informal, "on 
[date] I compared and adjusted this standard to Thomas's 732A that 
was just back from calibration and sanity-checked with a 3458A, using 
a [Fluke 845A null meter, or whatever]."  Knowing the published 
uncertainties of the 732A, I can even calculate the uncertainty of my 
732A as of the moment of calibration, and at intervals thereafter 
based on the published uncertainties.

Checking against another recently-calibrated 732A at a later date can 
confirm or deny that mine remains within the published uncertainty at 
that time.  If it does, that fact becomes part of my (informal) 
documentation.  If it doesn't, the presumption is that one of the 
732As is broken.  We can suspect that it is mine, but we cannot know 
that without further testing.

Best regards,

Charles