732A drift
My 732Ax-apple-data-detectors://28 e.g. has a drift of only about 0.2ppm pa over a couple of year
Hope you don't mind me jumping on this thread and asking a basic question: is there any kind of procedure for the 'enthusiast' (say with single 3458A/single 732 and not say 4x732) to measure the drift of a particular 732.
Alan
On 30/08/2017 17:33, Alan Ambrose wrote:
My 732Ax-apple-data-detectors://28 e.g. has a drift of only about 0.2ppm pa over a couple of year
Hope you don't mind me jumping on this thread and asking a basic question: is there any kind of procedure for the 'enthusiast' (say with single 3458A/single 732 and not say 4x732) to measure the drift of a particular 732.
Alan
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.
Not really, you have a Voltmeter and a 732b, they drift a little, how do you know which one is drifting, and by how
much? you cant know unless you have at least one other unit to compare with, then you can build a matrix of all the
relative drifts and then guess which one is actually the most accurate...
Hi, first post!
Yeah, I ran into this issue a while back. Fortunately for most applications 10mV resolution is fine (eg measuring charge state on Li-ion cells) but I did find that old meters do seem to experience random drift failures of precision resistors and more so trimpots. Would it be a good idea for someone to do a "732 FAQ" with likely faults that would cause a particular matrix of symptoms?
Also how do you deal with failures where a precision component has "gone bad" ? Surely all the calibrations are suspect which is why any sensible engineer always has two references at a bare minimum and sets up a master/slave or main/backup then maintains a calibration table of each? so if a drift is seen then the "bad" unit can be dealt with sternly.
I looked into making a 10.0000Vref a while back and had some success with active feedback via thermal pad: it almost worked but in the end it was cheaper and simpler to buy one ready made (cough REF02 /cough)
Also relevant, since originally buying my RS IDM65 you can now get I2C precision CT references which can replace the troublesome parts
with something that does not drift, ever!
-Andre
From: volt-nuts volt-nuts-bounces@febo.com on behalf of Alan Ambrose alan.ambrose@anagram.net
Sent: 30 August 2017 17:33
To: volt-nuts@febo.com
Subject: [volt-nuts] 732A drift
My 732Ax-apple-data-detectors://28 e.g. has a drift of only about 0.2ppm pa over a couple of year
Hope you don't mind me jumping on this thread and asking a basic question: is there any kind of procedure for the 'enthusiast' (say with single 3458A/single 732 and not say 4x732) to measure the drift of a particular 732.
Alan
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and follow the instructions there.
Alan:
The basic answer is NO. But a more expensive answer is to send the 732A
into FLUKE (or somewhere else that has a JJA) at regular intervals (i.e. 3
months) until you get a good idea of this unit's drift rate. This is why
these units tend to multiply in your collection until you have at least 4 so
that you can inter-compare the differences between all 4, doing a chart and
then you can pretty well estimate the drift of each unit.
See pages 34 - 36 in the FLUKE publication "Calibration Philosophy in
Practice 1st ed" at this URL
Another publication is NBS Technical Note #430 at this URL
While written for standard cells they apply just as well for solid state
voltage references like the 732A/B.
Also is a FLUKE Application Note "Fractional PPM traceablilty using your
FLUKE 734A/732B" at this URL
And "Maintaining 10 VDC at 0.3 PPM or Better in Your Laboratory" at this URL
I have used this method on my 732As for years and can estimate overall
drift of each one. I have 5 732As in the control chart. Of course
periodically one needs to be sent into FLUKE for certification as to it's
exact NIST voltage. While there is a lot of information in all of these
publications, I mainly depend upon the "Fluke Philosophy pp 34-36" methods.
While this may not satisfy the "purests", it works well for the hobbiest and
Voltnut.
Have fun,
Bill
----- Original Message -----
From: "Alan Ambrose" alan.ambrose@anagram.net
To: volt-nuts@febo.com
Sent: Wednesday, August 30, 2017 9:33 AM
Subject: [volt-nuts] 732A drift
My 732Ax-apple-data-detectors://28 e.g. has a drift of only about
0.2ppm pa over a couple of year
Hope you don't mind me jumping on this thread and asking a basic question:
is there any kind of procedure for the 'enthusiast' (say with single
3458A/single 732 and not say 4x732) to measure the drift of a particular
732.
and follow the instructions there.