Hi Adrian Oh I see...
But... I seem to recall the 720A also, similarly, requires linearity validation unless you just "assume" it is inherently linear? The manual shows a test using a second 720A! And that is "only" good to 0.2ppm. John [email protected] writes: > Hi John, > > sure, seems I should have been more clear. What I wanted to say is > that in order to have traceability starting from just a calibrated 10V > (and 10k) standard, which is sufficient to adjust a 3458A, you still > need some type of self-calibrating divider to validate the 3458A > (which then, once validated, can be your working unit). Or, if one > e.g. wants to calibrate a 5440 voltage calibrator from a 10V standard, > you also need a divider. Assuming a non-calibrated 3458A, because of > its highly linear ADC, can be used transferring the 10V into other > voltage ranges, is not valid, the 3458A has a performance validation > point that checks (within the testable limits) that the linearity is > ok. So no way around a divider unfortunately. > In the end, what we talk about is how do we get traceable volts > measurement capabilities (to the 10V standard that has been > calibrated, if one has a calibrated 1V too (of the 732A or whatever), > less work, but the basic problem remains). > > Adrian > > > >> Gesendet: Freitag, 24. April 2015 um 11:43 Uhr >> Von: "John Devereux" <[email protected]> >> An: [email protected] >> Betreff: Re: [volt-nuts] Advise to Junior Member Regarding >> Acquisition of Fluke 5XXX Series Calibrator >> >> [email protected] writes: >> >> > A few things to keep in mind: >> > - the 720A (and the 752A) are self-calibrating, i.e. you can (easily) >> > calibrate it yourself before use. The 3458A, using its external >> > artifact self-cal procedure based on only 10v and 10k, requires a >> > performance verification therafter (at least every second time, see >> > some military docs concluding this, I don't recall the link but easy >> > to find; i would actually say, to comply with GUM, every time). >> >> Hi Adrian >> >> I don't think that this point is a fair comparison, 3458a calibration is >> only required for absolute measurements which the 720A is incapable of >> anyway. >> >> John >> > > _______________________________________________ > 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. > -- John Devereux _______________________________________________ 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.
