Wow, +21C Delta on TEMP? is really huge for just a meter sitting alone on desk. There must be hot air blowing onto unit or dirty filter or faulty fan.
Even with old style fan cup, normal TEMP? - ambient Delta is 11-13C. New style fan filter even better, about 9-10C. Also reducing LTZ temperature would not help overall TC/ACAL performance as these effects are coming from different sources. Better and lower noise A1/A3 would be much more beneficial. BR, Illya xDevs.com On October 26, 2019 3:13:09 PM EDT, Philipp Cochems via volt-nuts <[email protected]> wrote: >Hi, > >one should always keep in mind that all the specifications are made to >achieve a certain yield in production. Assuming a Gaussian distribution >it >is not very unlikely, that we all have 3458As which perform much better >than specified. In that respect you cannot rely on vishay marketing. > >Reducing the LTZ1000 temperature is also not that easy. The 3458A might >be >a metrology grade DMM, but it is also a system DMM. Even on my bench >the >TEMP? sometimes goes up to 47°C (at 26°C room) and it might be even >higher >in the summer. And it is not in a rack and only a HP 3488A is sitting >on >top which produces almost no heat. Running the 3458A in a rack full of >equipment will not allow to reduce the LTZ1000 that much. > >I think the gap to the Fluke 8588A is too wide to catch up with only a >little bit improved specs. I think the main reason for the black >edition is >to ensure that many test rigs can work for the next years. > >Best regards >Philipp > >Am Sa., 26. Okt. 2019 um 20:48 Uhr schrieb Frank Stellmach < >[email protected]>: > >> @ Poul-Henning: >> It's improbable that we'll see improved specs. >> The presentation of the Black Edition already happened end of May, >and >> the validation obviously was already running. >> >> The description @ meilhaus already claims that no change in spec. >will >> happen, and the linked Black Edition specs are really identical. >> >> @ David and Bob: >> >> RoHS is a European requirement only, and may not (yet) apply to other >> markets. >> KS obviously has stocked a bunch of lead containing units (they >called >> it EU3458A) in their own premises before the exemption expired, and >as >> this stock would be depleted later, they needed to design a lead >free >> unit - initially for the EU market only. >> >> I suppose they will sell the white version outside the EU for several >> years, until their old component stock is depleted also. >> >> I wonder what will happen to the EU34420A, which has the same >problem, >> but lead free soldering might pose greater problems, due to e.m.f. @ >nV >> level. >> >> @ Tom: >> >> I can't tell anything about Golden Units, as I only own a regular, >white >> HP3458A from 2001, which still performs better than specification.. >> +1.8ppm drift only, over 9 years for DCV, and Ohm is also much more >> stable than specification, as far as I can judge. >> >> Ok, the trick is, that it does not run 24/365, and my LTZ reference >> board is set to ~ 65°C. >> >> Concerning the internal A/D converter clock, there are several papers >> about AC metrology, especially on AC power measurements, where the >PTB >> improved the accuracy greatly by optically linking the internal clock >to >> the rear of the 3458A, to mitigate the 10 or 100ns (?) clock phase >> jitter. See also Rado Lapuh, Sampling With 3458A, page 149. >> >> A practical schematic is not published, so it's very appreciated that >> you provide one, but a description, how to apply this clock would be >> necessary. >> >> Frank >> >> >> >> _______________________________________________ >> 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. BR, Illya Tsemenko _______________________________________________ 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.
