In my opinion the $2k+ JJ calibration would be massive overkill for anyone with a “normal” home lab. I am having a hard time justifying the $777 per incident calibration cost as I’m no longer providing services that require anywhere near the level of accuracy and the traceability it provides, nor do I maintain the lab environmental requirements as strictly as I once did. My 34401A is more than sufficient for what I do now; that’s part of what’s spurring the thinning of the herd.
Steve WB0DBS > On Jul 1, 2019, at 5:06 AM, David C. Partridge > <[email protected]> wrote: > > NMI - who/what are they remember that this David Kirkby and I are in UK and > other as well aren't in USA ... > > -----Original Message----- > From: volt-nuts [mailto:[email protected]] On Behalf Of Illya > Tsemenko > Sent: 01 July 2019 03:57 > To: Discussion of precise voltage measurement > Cc: 'Discussion of precise voltage measurement' > Subject: Re: [volt-nuts] What are the best of the low(ish) cost 8.5 digit > multimeters? > > Calibrating 8.5d meter is a challenge, but it's not as bad to need JVS. Even > with that, Your nearest NMI will be happy to provide you top notch > calibration, that is magnitude better than even 24 hour specification of the > meter, be it 3458A or whatnot. Main power of the 3458A that makes it so > special is ultra-linear ADC (which is very fragile), which makes feature > like ACAL self-calibration possible with just known 10V and 10k. So if one > to buy 8.5d meter for business purposes, getting cheaper meter + paying for > full calibration with data might be well the same as getting used 3458A, > *IF* lab has known 10V/10kOmega standards or want to invest in those. > > I've recently got calibration by NMI directly vs JVS/QHR on my references > (U=0.02ppm 10V and 0.16ppm 10kOhm), hand-carry those home, calibrated my > 3458A's and 5720A and same day performance verification yield results well > under 24 hour specifications of HP3458A/002. Even INL data for 3 out of 4 is > well inside "typical" 0.05ppm from HP: > https://xdevs.com/doc/HP_Agilent_Keysight/3458A/test/INL_10V_3458abcd.png > Sure, one has to have high-performance MFC, but giving the amount of DMMs I > have, trying to ship (international air shipping is no fun) even fraction on > them to standards lab calibration would cost more than getting own > calibrator and getting that in shape. > > Currently doing some more tests, but I will be listing one fully-calibrated > 3458A, need to cut the TEA pile. AFAIK Keysight Loveland Standards Lab > calibration is >$2.2K shipping/handling excluded. With 8.5d anything, it's > pretty much pay to play game, either way with "cheap" meter and expensive > calibrations, or expensive meter and...expensive calibrations :) No > exceptions. > > Datron 1271/1281 have also 100% overrange, so it can measure up to > 200mV/2V/20V/200V/1kV, which might not be obvious on first glance thru spec > sheet ;). > > P.S. As happy K2002 owner, DMM7510 not even in the same league, sorry. > Hurdles with logging/fancy histograms do not sound serious in 2019, given > plenty of free open-source options available to interface and log meter > data. All one need is GPIB interface and RaspberryPi or alike, and few > evenings to figure out the basics. > > > > > ---- On Mon, 01 Jul 2019 10:28:37 +0800 David C. Partridge > <mailto:[email protected]> wrote ---- > > > Sad to say that Ametek no longer provide any support for the 7081. They also > scrapped the Commodore PETs they had with the calibration software for the > 7071 and 7081 (I so wish I could have acquired one of those). > > The huge "elephant in the room" problem is finding a calibration lab with an > error budget that's actually good enough to calibrate *any* 8.5 digit meter. > More like than not (barring faults) your meter will probably be more > accurate and stable than any of their calibration equipment. I don't know > of any in the UK apart from Fluke and Keysight (I would love to hear that > there are others). Keysight UK can't do the top spec calibration on a > 3458A (so called Loveland calibration) so if you want that, AFAIK it has be > return shipped to California, USA (though I've heard that Germany *may* have > a Josephson junction setup). Of course it's not under power for that time > and you risk destruction of the custom VFDs ... > > I suspect that my Datron 4808 is as good as or better than most cal labs in > the UK (though there must be some with at least one calibrated Fluke > 5700A/5720A/5730A or Datron 4808 or similar). > > PS Transmille produce an 8ppm calibrator (4010) and a 4/9ppm meter (8100) so > could probably do the job, but whether they'd do "other brand" calibration ? > > > David > > -----Original Message----- > From: volt-nuts [mailto:mailto:[email protected]] On Behalf > Of J. L. Trantham > Sent: 01 July 2019 01:21 > To: 'Discussion of precise voltage measurement' > Subject: Re: [volt-nuts] What are the best of the low(ish) cost 8.5 digit > multimeters? > > David, > > Have you considered the Solartron/Ametek 7081? > > If I'm not mistaken, you posted some images of their EPROM's several years > ago. > > It's slow sampling at 8.5 digit resolution but seems user friendly and, at > least several years ago, was able to be calibrated by Ametek in England. I > sent two over there for calibration. > > Good luck. > > Joe > > > _______________________________________________ > volt-nuts mailing list -- mailto:[email protected] > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/volt-nuts_lists.febo.com > and follow the instructions there. > _______________________________________________ > volt-nuts mailing list -- [email protected] > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/volt-nuts_lists.febo.com > and follow the instructions there. > > > _______________________________________________ > volt-nuts mailing list -- [email protected] > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/volt-nuts_lists.febo.com > and follow the instructions there. _______________________________________________ volt-nuts mailing list -- [email protected] To unsubscribe, go to http://lists.febo.com/mailman/listinfo/volt-nuts_lists.febo.com and follow the instructions there.
