Products > Test Equipment
Brymen 257S lost calibration data
retiredcaps:
The AM-160 in Martin's video is definitely out of calibration.
According to the AM-160 manual, the spec for the 50V DC range and below is 0.02% + 2D. Note: Martin incorrectly states the specs in his video. See manual for confirmation of the 0.02% + 2 digit.
http://content.amprobe.com/manualsA/AM-140-A_AM-160-A_DMM_Manual.pdf
In Martin's video, it shows 5.0021 for the 5.0000 range (12:05).
5.0000 x 1.0002 = 5.0010 + 2 digits = 5.0012 (upper bound). Martin's AM-160 is 9 counts out.
In Martin's video, it shows 1.5007 for the 1.5000 range (11:50 - Martin is incorrect in saying the 1.5007 is in spec).
1.5000 x 1.0002 = 1.5003 + 2 digits = 1.5005 (upper bound). Martin's AM-160 is 2 counts out.
So again, it looks like the 5V range and below are out of calibration, brand new out of the box.
mikerj:
--- Quote from: retiredcaps on November 21, 2015, 09:42:28 pm ---The interesting question for Brymen is how the meter knows there is a Calibration error? Maybe during bootup, the main IC can't read the calibration constants/offsets and thus reports calibration error?
--- End quote ---
I'd suspect that cal values are stored with a checksum, and if the checksum fails you get a warning. Just wondering if oxidised battery contacts caused the initial symptoms (turning itself on and off) and the micro inside had a fit and wiped over some NV data? Not a great design if this is the case.
Sjokolade:
Strange thing is that batteries seems fine now, no more low battery warning using the original batteries - no leakage and contacts seems to be just fine. I would think that when you get a low battery warning they last for several hours more and not like mine meter that turned off a few seconds after warning was flickering on/off.
Sjokolade:
Heard back from Brymen today.
--- Quote ---Hi,
Your BM257s unit needs recalibration. Please contact the agent for the calibration service.
Best Regards,
Gary Wang
Product Marketing Manager/Brymen
--- End quote ---
retiredcaps:
--- Quote from: Sjokolade on November 23, 2015, 05:01:53 pm ---Heard back from Brymen today.
--- Quote ---Your BM257s unit needs recalibration. Please contact the agent for the calibration service.
--- End quote ---
--- End quote ---
I would have expected the wording to say
Please contact the agent for the warranty service.
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