[volt-nuts] Advise to Junior Member Regarding Acquisition of Fluke 5XXX Series Calibrator

[acbern at gmx.de]

Hi John,

well, if one wanted to use a 720A, only the 0.1 and 0.01 settings are needed, so full linearity check over all decades is not needed. A second 720A to do that is not really precise enough, as the manual also states. But anyway, the preferred divider to use is the 752A.

Adrian

> Gesendet: Freitag, 24. April 2015 um 16:08 Uhr
> Von: "John Devereux" <john at devereux.me.uk>
> An: volt-nuts at febo.com
> Betreff: Re: [volt-nuts] Advise to Junior Member Regarding Acquisition of Fluke	5XXX Series Calibrator
>
> 
> 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
> 
> 
> 
> acbern at gmx.de 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" <john at devereux.me.uk>
> >> An: volt-nuts at febo.com
> >> Betreff: Re: [volt-nuts] Advise to Junior Member Regarding
> >> Acquisition of Fluke 5XXX Series Calibrator
> >>
> >> acbern at gmx.de 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
> >> 
> >  
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> 
> -- 
> 
> John Devereux
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