-a calibration certificate without uncertainsties is totally useless. in is not even a calibration. -I have never understood why people are so keen on getting things calibrated at Keysight.
> Gesendet: Donnerstag, 19. April 2018 um 14:08 Uhr > Von: "Dr. David Kirkby" <drkir...@kirkbymicrowave.co.uk> > An: "Discussion of precise voltage measurement" <volt-nuts@febo.com> > Betreff: [volt-nuts] Would you be concerned if the manufacturer does not have > an uncertainty budget, so can't provide uncertainties in a calibration? > > I have an HP 4339B high resistance meter. It can read up to 1.6 x 10^16 > ohms, with a basic uncertainty of 0.6%. It has a built in voltage source of > up to 1 kV. > > I've contacted Keysight (UK) and asked for calibration cost, with > uncertainties, for this 4339B. However, they have said they can't provide a > calibration with uncertainties, and when I asked why, they have said they > do not have an uncertainty budget available that suites that model. Looking > at the Keysight website, a calibration with uncertainties is available in > the USA, but I guess for whatever reason Keysight UK don't have this > ability on this specific instrument. On other instruments I have sent them, > I have never had this issue. > > I expect if I really wanted to, I could get it shipped to the USA and > calibrated there, but I can't justify the costs that would be incurred if > it was shipped to the USA and back. > > From a practical perspective, I don't really need the uncertainties - it > was more for interest sake. I also have a reasonable degree of confidence > that as a reputable company, Keysight would not calibrate an instrument > unless they were confident they could determine if it is in or out of > specification. > > The 4339B is a pretty obscure unit, requiring resistors up to 10^11 ohms to > calibrate it. > > I'm sending this to Keysight with a blank EEPROM, so there will be no > calibration data whatsoever in the instrument. Hopefully that means > everything will be set right, and so likely to stay in specification longer > than it might otherwise do so. There are no trimmers in the 4339B - all > calibration is via the EEPROM. A 3458A is used for calibration of the > voltage source. I'm confidence the voltages will be measured accurately > enough, but a bit less confident about the values of the resistors used for > calibration. > > Dave > > Dr David Kirkby Ph.D C.Eng MIET > Kirkby Microwave Ltd > Registered office: Stokes Hall Lodge, Burnham Rd, Althorne, CHELMSFORD, > Essex, CM3 6DT, United Kingdom. > Registered in England and Wales as company number 08914892 > http://www.kirkbymicrowave.co.uk/ > Tel 01621-680100 / +44 1621-680100 > _______________________________________________ > volt-nuts mailing list -- volt-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts > and follow the instructions there. > _______________________________________________ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there.