In classic instrument management, the term "check" has been used.Now it is called calibration in measurement management.Calibration is the whole job of determining the indication error(including determining other metering performance if necessary) of a measuring instrument.
I. Differences and similarities between calibration and verification
Calibration and verification are two different concepts, but there is a close relationship between the two. Calibration is compared a measuring instrument (referred to as a standard instrument) with a higher accuracy than the calibrated measuring instrument with the calibrated measuring instrument to determine the indication error of the calibrated measuring instrument,and sometimes also including some measuring performance,but the calibrated measuring instruments only need to determine the indication error.If the calibration is the verification content of the indication error in the verification work,it can be said that it is part of the verification work,but the calibration cannot be regarded as the verification.Moreover, the calibration requirements are not as strict as the verification, and the calibration can be performed at the production site, and the verification must be carried out in the verification room.
Some people understand calibration as the process of adjusting the measuring instrument to the specified error range,which is not accurate enough.Although it can be adjusted during the calibration process, the adjustment is not equal to the calibration.
II. Basic requirements for calibration
The basic requirements for calibration should be as follows:
(1) Environmental conditions,if the calibration is carried out in the verification (calibration) room, the environmental conditions should meet the temperature, humidity and other regulations required by the laboratory. If the calibration is carried out on site, the environmental conditions shall be subject to the conditions that instrument can be used on-site.
(2) The instrument, as a standard instrument for calibration,the error limit should be 1/3~1/10 of the error limit of the calibrated instrument.
(3) Personnel, although the calibration is different from the verification, the personnel who perform the calibration should also be effectively assessed and obtain the corresponding certificate.Only the certificate holder can issue the calibration certificate and calibration report, and only such certificate and report can be considered effective.