Calibration -- the use of this word - Page 1
Forum section: electronics / general

author: glarsson
author_rank: Frequent Contributor
timestamp: December 18, 2017, 07:46:44 pm
content: As we all know calibration is the process of comparing what an instrument measures to a known source and noting the differences, if any.The notes can later be used to fudge measurements or just kept as a track of drift over time.Any repair and adjustment of the instrument is not part of the calibration process.So, why do the many companies use the work calibration for something else? Many instruments from the both big and small companies have calibration menus, calibration instructions in manuals, etc. All of these "calibration" procedures involves adjustments of the instrument, either done automatically by the instrument (input known signal) or by the user (entering what a different instrument measures).Why this discrepancy?

author: ataradov
author_rank: Super Contributor
timestamp: December 18, 2017, 08:08:02 pm
content: This is the difference between pure scientific and conventional uses of a word. I personally don't get that comparing to a known standard definition. I want my instrument to show the reading as true as possible, I don't want to reference some paperwork to make adjustments to my measurements. That's just stupid.It all probably made sense when instruments could not be easily adjusted, but with digital instruments, I see no point in a pure "calibration". If you know the offset - just program it into the instrument.

author: VintageNut
author_rank: Frequent Contributor
timestamp: December 18, 2017, 08:31:11 pm
content: Non-metrologists using a technical metrology term. Happens all the time in many professions.I just roll my eyes when my girlfriend tells me that her $40 bathroom scale is "self calibrating". I try to explain the term "tare" but it is wasted energy. Its much more productive for me to just roll my eyes and maybe add a derisive chortle.

author: tautech
author_rank: Super Contributor
timestamp: December 18, 2017, 08:33:14 pm
content: No, it's a misunderstanding of terminology.FirstVerificationthat an instrument meets spec OR not. Often this enough and a calibration certificate can be issued.Then adjustment and/or repair takes place to have the instrument meet spec with traceable calibrated reference instruments.Then adatedcalibration certificate is issued specifying the calibrated/repaired instrument AND all reference instruments used for the adjustment/calibration to meet the instruments manufacturers spec. All reference instrument's calibration certificate #'s and calibration expiry dates are listed too.The whole process and supporting documentation must be fully traceable.

author: dl1640
author_rank: Regular Contributor
timestamp: December 19, 2017, 02:51:10 pm
content: Standards and tools used for calibration and adjustment may be similar, also the operation procedure may be same.Difference is whether we compensate against the reference value or not, mechanically or electronically.I guess the word calibration is used for both intention: calibration or adjustment, in the past, for convenience...However some instrument cannot be adjusted such as resistors, we can only use its true value/calibrated value.Normally instruments need to be adjusted are not so accurate ones, and easy operate ones, they need to ensure its value within spec all the time. Not like calibration standards which need drift history and can be used as their true value, may not need adjustment in life cycle.