Hi David, Yes, the meter has been on for days already. It had just done a long run into a shorting plug that shows much better stability, I suspect a tempco in the opto-isolators that transfer the reference volts, but will carefully consider all possible sources first. The other option is the input bias current that Mickle found.
Regards, M K > From: [email protected] > To: [email protected] > Date: Sun, 20 Jan 2013 11:13:00 +0000 > Subject: Re: [volt-nuts] 7081 resistance accuracy issue > > How long had the meter been powered on for when you started the test? Think > days rather than hours to stabilise. > > D. > -----Original Message----- > From: [email protected] [mailto:[email protected]] On > Behalf Of m k > Sent: 20 January 2013 09:06 > To: [email protected] > Subject: [volt-nuts] 7081 resistance accuracy issue > > > Hi everyone, > > As part of my checking over of the behaviour of the 7081 I ran "mode,testk" > and "nines=8" overnight, the result is a swing larger than I would expect! > > max 166.00455 > min 166.00040 > this means a 25 ppm shift > > The circuit is meant to generate a constant current, so if that constant > current can vary by 25ppm over a 20-23 degree house temperature then it is > only accurate to 25ppm for resistance measurement except when used as a > transfer standard. > > anyone else find a similar shift? > > M K > > _______________________________________________ > volt-nuts mailing list -- [email protected] To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts > and follow the instructions there. > > _______________________________________________ > volt-nuts mailing list -- [email protected] > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts > and follow the instructions there. _______________________________________________ volt-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there.
