121GW Calibration table in current manual, excess text in certain fields inacces - Page 1
Forum section: electronics / testgear

author: n3mmr
author_rank: Regular Contributor
timestamp: January 17, 2022, 12:50:51 pm
content: The calibration able on p 73 in the latest manual has fields where some of the text is invisible.Does anyone here know what it is supposed contain?

author: Dr. Frank
author_rank: Super Contributor
timestamp: January 17, 2022, 01:59:06 pm
content: The latest revision on eevblog is March-2020, and there is (and always was) a calibration table on p. 71 only.This always had been scrambled, but as far as I remember, we were able to reconstruct the necessary parameters.Therefore, please identify correctly the revision you are referring to (is there a newer one?), and the lines / parameters you are missing.I could then search in my repository about this issue.Frank

author: n3mmr
author_rank: Regular Contributor
timestamp: January 17, 2022, 02:42:20 pm
content: You're right, it's on p71 and it's the March 2020 revision.

author: n3mmr
author_rank: Regular Contributor
timestamp: January 17, 2022, 02:55:53 pm
content: The following fields are possibly (or certainly) truncatedIAP Start mode:Cal Mode Start:Cal Mode Key:LowZ/R1DCV and ACV/R2,R3PeakHold/R0Capacitor/OFFSET

author: Dr. Frank
author_rank: Super Contributor
timestamp: January 17, 2022, 04:31:50 pm
content: Quote from: n3mmr on January 17, 2022, 02:55:53 pmPlease follow the detailed descriptions for these three items in the chapters: Calibration Mode, Zero Offset Calibration, Full Scale Gain Calibration and Firmware Update.Quote from: n3mmr on January 17, 2022, 02:55:53 pm".. are not available"Quote from: n3mmr on January 17, 2022, 02:55:53 pmThat's 500.00V and 600.0V in both cases. These are the necessary test signals for full scale calibration only.Quote from: n3mmr on January 17, 2022, 02:55:53 pm".. at AC5V Range". Sorry, I can't describe, what's exactly necessary here, as I did never calibrate this mode. Maybe it's not necessary, as zero offset does not show up in the according chapter for this mode.Quote from: n3mmr on January 17, 2022, 02:55:53 pmHere again, I can't tell, what's to be done here, as I never tried that calibration. This mode also does not show up in the zero offset chapter.I speculate, that you need to calibrate zero only in R1 = 100nF range, with open jacks, or if you want to include your standard test cables, with latter left open.The 50MOhm range is also calibrated at 50000 counts, i.e. 50MOhm, not @ 40MOhm.Just another general remark. The calibration of this DMM (as well as other 5000 / 6000 count DMMs) require special calibrators which provides these specific F.S. signals for resistance and capacitance, instead of the usual fixed values like 10000 / 19000 Ohm.That is done by a method called synthesized impedance, i.e. which outputs fully variable calibration stimuli, as in the FLUKE calibrator 5500A.Frank

author: n3mmr
author_rank: Regular Contributor
timestamp: January 20, 2022, 08:31:27 am
content: Ok, thank you Frank, I found your advice useful, and I got a bit further with my "pseudocalibration" effort.However, what I really want to know is what text those fields actually contained!