Products > Test Equipment
Test Equipment Anonymous (TEA) group therapy thread
bd139:
Welcome to voltnuttery.
Specmaster:
Haha, your the one who has no faith in his current calibration and is getting it done professionally >:D
You're right though, years ago with analogue meters it was not so important but with the advent of digital everything it seems that we have gone stir crazy on getting everything to match and digits to switch over at the same time etc because we can see things in so much more clarity. Before just viewing just slightly away from dead centre would make slight differences but no-one really worried so much did they?
Cerebus:
--- Quote from: Specmaster on May 23, 2018, 07:44:26 pm ---... the only other lab remotely near me is Calmet, who say that can do it but it is not known to how many digits, unless bd139 does as he spoke to them?
--- End quote ---
To more digits than you've got. Calmet's UKAS accreditation details can be found here https://www.ukas.com/wp-content/uploads/schedule_uploads/00001/0143Calibration%20Multiple.pdf. The limit on their capabilities (for artefact calibrated meters like the HP 3458A) is their sourcing capability for standard quantities like 10 V (0.8ppm k=2) or 10kΩ (3.0 ppm k=2).
For more mundane calibrations their generation capability (i.e. the output of a variable calibrator) for resistance is ~25 ppm, DC voltage ~35ppm, AC voltage ~200-300ppm (all with an expanded uncertainty with k=2 i.e. the standard deviation of any error is 1/2 the stated number). I'm just picking values for middling ranges there, you can see full details in the UKAS accreditation.
Specmaster:
--- Quote from: Cerebus on May 23, 2018, 08:51:09 pm ---
--- Quote from: Specmaster on May 23, 2018, 07:44:26 pm ---... the only other lab remotely near me is Calmet, who say that can do it but it is not known to how many digits, unless bd139 does as he spoke to them?
--- End quote ---
To more digits than you've got. Calmet's UKAS accreditation details can be found here https://www.ukas.com/wp-content/uploads/schedule_uploads/00001/0143Calibration%20Multiple.pdf. The limit on their capabilities (for artefact calibrated meters like the HP 3458A) is their sourcing capability for standard quantities like 10 V (0.8ppm k=2) or 10kΩ (3.0 ppm k=2).
For more mundane calibrations their generation capability (i.e. the output of a variable calibrator) for resistance is ~25 ppm, DC voltage ~35ppm, AC voltage ~200-300ppm (all with an expanded uncertainty with k=2 i.e. the standard deviation of any error is 1/2 the stated number). I'm just picking values for middling ranges there, you can see full details in the UKAS accreditation.
--- End quote ---
Thanks, thats a lot more detail than RS provide for their certification details of which are here https://uk.rs-online.com/web/generalDisplay.html?id=aboutRS/our-certifications but they also have UKAS accreditation and yet were unable to calibrate my poor lowly (by today's standards) 3478A.
Yet I have managed it at home without all of their complicated gear, admittedly it might be a few ppm out but certainly near enough for my simple needs. I don't need to have it 100% bang on for fear of being inspected etc as I'm not carrying out a commercial operation of any kind.
Cerebus:
RS's Schedule of Accreditation is here. It would be a lot easier if RS made it clearly available, rather than having to hunt it down via UKAS.
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