Brooke,   I had the very same encounter in 1989/1990. I received the new 3458A in November 1989, and only 1 month later, on 1st January 1990, the New Volt (SI-1990) went effective. As my instrument came directly from the U.S., the difference in calibration was 9.264ppm, which the instrument now was reading high.   You may read my whole volt-nuts story related to this SI - change here:   http://www.eevblog.com/forum/metrology/1000-my-(hi)story-of-the-weston-cell-of-the-volt-and-of-being-a-volt-nuts/.   The 332B might not have been your reference standard, as its uncertainty is 10ppm / 60days only.   Maybe you had a 732A, or a bank of Weston cells in your lab, otherwise this change could not securely be observed by a solitary Fluke 33xB/D.   best regards Frank --- Die Bundesliga hat begonnen! Alle Tore, alle Ergebnisse, alle News: Pocket Liga jetzt im AppStore oder Google Play Store herunterladen - kostenlos!

Hi Frank: Thanks very much. I'm 99.999% sure the 332 is the instrument used. Not in the sense that it was accurate, but in the sense it could supply a voltage that stayed the same for a few minutes while it was read with the "old volt" 3458 then the "new volt" 3458. http://www.prc68.com/I/Fluke332B.html -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html The lesser of evils is still evil. -------- Original Message -------- > Brooke, > > I had the very same encounter in 1989/1990. > I received the new 3458A in November 1989, and only 1 month later, on 1st January 1990, the New Volt (SI-1990) went effective. > As my instrument came directly from the U.S., the difference in calibration was 9.264ppm, which the instrument now was reading high. > > You may read my whole volt-nuts story related to this SI - change here: > > http://www.eevblog.com/forum/metrology/1000-my-(hi)story-of-the-weston-cell-of-the-volt-and-of-being-a-volt-nuts/. > > The 332B might not have been your reference standard, as its uncertainty is 10ppm / 60days only. > > Maybe you had a 732A, or a bank of Weston cells in your lab, otherwise this change could not securely be observed by a solitary Fluke 33xB/D. > > best regards > Frank > > > --- > Die Bundesliga hat begonnen! Alle Tore, alle Ergebnisse, alle News: Pocket Liga jetzt im AppStore oder Google Play Store herunterladen - kostenlos! > _______________________________________________ > 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. >