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Old 20th Jun 2018, 7:53 am   #71
G0HZU_JMR
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Join Date: Sep 2010
Location: Cheltenham, Gloucestershire, UK.
Posts: 3,077
Default Re: Meter Suggestions for Basic Alignment/Calibration

Yes, don't forget this thread is mainly about suggestions about calibrating an AVO 8. Presumably this puts things in the ballpark of +/-1% even before temperature and linearity are considered. The calibrating meter probably needs to be several times more accurate than this and 0.1% is probably overdoing it.

My old Maplin 3.5 digit DMM I bought in the 1980s isn't a professional grade DMM but if it went out of cal by 1% I'd consider binning it. I think the spec for my Fluke 45 is 0.025% plus a couple of LSDs and the Keithley meters are something like an order of magnitude better than this. If any of them ever drift by double their spec I'd be surprised and a bit disappointed. But the Keithley could drift 10 times out of spec and still be way too good for my needs.

If I'd calibrated my Keithley 2015 meter every year I'd probably have spent over a thousand pounds on 'calibration' by now! That would be several times the initial cost of the meter.

That's why I offered the advice not to bother with calibrating the Fluke 287. Unless it develops a fault it is going to be way better than an ageing AVO 8 meter movement.
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Regards, Jeremy G0HZU

Last edited by G0HZU_JMR; 20th Jun 2018 at 8:18 am.
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