[volt-nuts] Reference Calibration Options - Solartron7081andFluke 731B and 335A

[Fred Schneider]

Is it better to leave my keithly on for a few weeks to burn in ? Or just 24/7/365. 
I left the references on, but not the meter, that stabelizes after about an hour and the shift is only a few ppm. I bought it new and do not want to wear it down quick, but reading all this i think it will be shift the most when new and if the Vref in the 2000 is burned in it will stablize. So after a certain time ( howlong ? ) you adjust it, or do a software calibration and then the meter will stay better within specs ? Is that correct.

The 7061 does not stay on, it gets so hot I do not dare to leave it on unattended until I find a Service manual and be able to check everything inside.

Fred PA4TIM

Op 10 sep. 2011 om 10:32 heeft "gbusg" <gbusg at comcast.net> het volgende geschreven:

> Fred wrote:
> 
>> How do you know the standards drift and not the meters?
> 
> Josephson Array
> 
>> Yesterday i turned on the 7061 again and it showed 1.000,006,2 V after
>> three hours it was 1.000,000,1 V and stayed there, so keeping it powered on
>> seems to work better.
> 
> Yes, effectively you were characterizing the warm-up characteristics of your
> 7061. Obviously don't depend on it for the best accuracy and stability right 
> after
> power-up.
> 
>> have last week adjusted to 1.000,000 V on the keithley 2000.
>> After a week it was 1.000,046 but I adjusted it to 1 V  again. But the
>> reference in that has only about 150 hours burn in time total. The Short
>> time drift is now allmost gone. It flips + 1 uV now and then, but it could
>> be it is adjusted to 1.000,000,8 or so.
> 
> Yeah, I would definitely leave your Keithley 2000 running 24/7 for the
> foreseeable future, while you're running these kinds of experiments.
> 
> Keep up the good work and experimenting, Fred!
> 
> -Greg
> 
> 
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