I too, highly recommend this book. Once I started reading it I couldn't
stop, and read it from cover to cover probably twice.
Regards,
Mitch
----- Original Message -----
From: "Robert Atkinson" <[email protected]>
To: "Discussion of precise voltage measurement" <[email protected]>
Sent: Monday, July 29, 2013 2:28 PM
Subject: Re: [volt-nuts] What really gets calibrated? A reference
For those who have not heard of it, Fluke's "Calibration: Philosophy in
Practice" is an excellent reference and quite readable. I got a copy as a
holiday gift last year.
Robert G8RPI.
________________________________
From: Didier Juges <[email protected]>
To: Discussion of precise voltage measurement <[email protected]>
Sent: Monday, 29 July 2013, 18:56
Subject: Re: [volt-nuts] What really gets calibrated?
The big difference is that nowadays, adjustment is done in software without
moving parts. There is no wear out involved in doing frequent adjustment and
through the software you can record by how much each setting was adjusted.
These were the main reasons for not adjusting an instrument that was in spec
when going to the cal lab.
Didier KO4BB
Orin Eman <[email protected]> wrote:
On Mon, Jul 29, 2013 at 12:25 AM, David Kirkby
<[email protected]>wrote:
On 28 July 2013 23:15, Joseph Gray <[email protected]> wrote:
> I recently had it explained to me that "calibration" is really just
> checking a piece of gear against a known standard, to see if it
meets the
> manufacturers specification. If it is outside specified values,
then it
> gets "adjusted", not "calibrated".
I think it depends somewhat on who cals it, and under what conditions
are stated.
I think if something is specified with an uncertainty of 10%, and is
found to be 9.9% off, then I feel it should be adjusted as it is
close
to the limits of being acceptable, even though it is within spec.
Certainly with Agilent, you will pay more for the cal if you want
both
"before" and "after" data.
Here is what Agilent say about the new 3446xA DMMS:
"Adjustment is Recommended
Whatever calibration interval you select, Agilent Technologies
recommends
that complete re-adjustment should
always be performed at the calibration interval. This ensures that the
instrument will remain within specifications for
the next calibration interval and provides the best long-term
stability.
Performance data measured during performance
verification tests does not mean that the instrument will remain within
these limits unless the adjustments are
performed. Use the calibration count to verify that all adjustments
have
been performed. "
This is however, a closed box calibration where the calibration process
stores correction constants in non-volatile memory. There are no
concerns
about flaky trimpots etc..
Orin.
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Sent from my Motorola Droid Razr 4G LTE wireless tracker while I do other
things.
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