Thomas wrote:
True the documentation is not there but does that matter in a majority of Volt-Nut applications.
If the documentation has not been done, there is no basis upon which to make ANY claim about the accuracy of a calibration. Really, the documentation IS the calibration. Having a voltage standard that is exactly 10.000000v but not knowing for sure what the voltage or the calibration uncertainty is, is no better than having a voltage standard that is tens of uV off and not knowing for sure what the voltage is. The documentation is the only way the adjustment becomes useful -- now you know exactly how far you can have confidence in the voltage. Indeed, a standard that is tens of uV off is a perfectly fine standard as long as you know the uncertainty -- which you would only if the documentation has been done. So yes, the documentation is absolutely critical to any calibration, accredited or not. And no commercial lab that puts in the extreme effort to document its results to the 1 ppm level or better is going to pass on accreditation, because it would seriously limit their business.
And if you ship VS local calibration you may have documentation stating lower uncertainty, but a local cal may actually be more accurate.
There are mountains of data on 732As that get shipped to Fluke every year, and there is no problem getting uncertainties at the 0.1 ppm level back at the customer's facility. This is just a non-issue with 732As. (The same is true of humidity, and temperature as long as you stay within 5C of the cal temperature.)
I also think the number of JJA's is larger then most think. Just this week a couple labs added 10 Volt Programmable Josephson voltage standards
The number of JJAs deployed is not the issue -- lots of research facilities have them, but they do not calibrate third-party instruments. For someone wanting to get an instrument calibrated, the question is, how many commercial calibration labs have them? And the answer is, only a very, very few. As I said before, take a look at the NVLAP lab certifications.
Best regards, Charles _______________________________________________ volt-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there.
