bk precision 2831e calibration - Page 1
Forum section: electronics / testgear

author: fqahmad66
author_rank: Regular Contributor
timestamp: January 11, 2022, 09:46:26 am
content: Happy new year to everybody...I just got a bk precision 2831e which needs caliberation. Is there a way to caliberate it at home using voltage references? I am quite aged, retired and cannot afford to send it to some proffessional caliberater. Thanks in advance.Best regards

author: alm
author_rank: Super Contributor
timestamp: January 11, 2022, 10:13:22 am
content: What do you mean with calibration? A performance verification, or an adjustment? Why do you think it needs either?I don't see any instructions for performance verification or adjustment in the manual. So I'm guessing about what might be necessary.You can probably do a limit performance verification with a basic voltage reference (like those fromhttps://voltagestandard.com/), but it will be limited to a few of the DCV ranges. Expanding it into higher voltage rangesis feasible.You may also manage to find some decent resistors that allow you to verify resistance ranges. AC is tricky: you may be able to do the lower voltage ranges with a function generator and another DMM, but the higher ranges are problematic.As for adjustment, probably not. Only if it allows to adjust a single function / range, then you might be. But a full adjustment will likely require things like 1000 VDC or 750 VAC 1 kHz. I'm not even sure if the manual tells you how to do adjustment.

author: fqahmad66
author_rank: Regular Contributor
timestamp: January 11, 2022, 04:42:32 pm
content: Thanks. I checked a few 0.01% resistors, and it measure almost within specs. The voltage has 4mV offset in auto mode even if I zero it out. It is is +4mV when connected normally and -4mV when measuring same with reverse leads. it is same if measured 1V up to 30V. Perhaps stray as it is just a two wire measuring instrument. The calibration seems to done through software as it has no adjustable pots or any precision reference. Teardown herehttp://katzelectronics.blogspot.com/2015/07/b-2831e-digitial-multimeter-review.html

author: alm
author_rank: Super Contributor
timestamp: January 11, 2022, 05:35:02 pm
content: Looking at thedata sheet, this may well be in spec. For the 200mV and 2V DC ranges, the specs are only while using REL mode to subtract any offset. And for the 20V range, the spec is 0.04% of value plus 0.09% of range. So that's up to 18mV offset.Based on this, I would maybe do some more confidence checks, but as long as you have no evidence that it's out of spec, I wouldn't attempt to adjust anything.

author: bdunham7
author_rank: Super Contributor
timestamp: January 11, 2022, 06:18:19 pm
content: Can you describe how you are testing that? If you have +4mVDC with the leads one way and -4mVDC the other way, that suggests that there is actually 4mVDC there somewhere. Testing a meter for zero calibration is typically done with a shorting plug, letting it settle thermally for a long time.If you do that and still want to zero it, just search the entire forum for "BK 2831E" and there's a thread there somewhere that describes how to get into the zero cal menu. If you want to do any further calibration, setting the calibration constants requires specific software and a calibrator that can supply all off the required inputs. You can't just do it manually with an odd assortment of references. I've worked on a few of these and if they are off, the zero cal procedure is generally enough to set them straight.

author: fqahmad66
author_rank: Regular Contributor
timestamp: January 13, 2022, 05:00:31 am
content: Thanks. 6666 zero cal did it. Now the meter is measuring within specs and no reverse leads offset. I used this from Far East..Best RegardsFarooq