The term "verification" has always been used in classic instrument management, and now it is called "calibration" in metrology management. Calibration is the entire work of determining the indication error of a measuring instrument (including determining other metrological performance when necessary). In the process of instrument maintenance, instrument calibration is a very common term. In general small faults, calibration becomes particularly important. Xi'an Antai Testing Equipment Co., Ltd. is a professional company focusing on instrument sales and system integration in the fields of electronic testing and industrial testing. It has long been committed to the development of testing technology, product matching and other industries in the fields of national defense, education, aerospace, industrial electronic manufacturing, scientific research, electric power, petrochemicals, metrology and testing, and provides good technical services to engineers. In previous maintenance work experience, calibration has become a necessary method for testing instruments.

1. Differences between calibration and verification

Calibration and verification are two different concepts, but there is a close connection between the two. Calibration generally uses a measuring instrument with higher accuracy than the calibrated measuring instrument (called a standard instrument) to compare with the calibrated measuring instrument to determine the indication error of the calibrated measuring instrument, and sometimes also includes some metrological performance, but often the calibrated measuring instrument only needs to determine the indication error. If calibration is the verification content of the indication error in the verification work, then calibration can be said to be a part of the verification work, but calibration cannot be regarded as verification. Moreover, the requirements for conditions for calibration are not as strict as those for verification. Calibration work can be carried out at the production site, while 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 adjustments can be made during the calibration process, adjustment is not equal to calibration.

2. Basic requirements for calibration

The basic requirements that calibration should meet are as follows:

1) Environmental conditions: If 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 calibration is carried out on site, the environmental conditions shall be based on the conditions that can meet the on-site use of the instrument.

2) Instrument: The error limit of the standard instrument used for calibration should be 1/3~1/10 of the error limit of the calibrated instrument.

3) Personnel: Although calibration is different from verification, the personnel who perform calibration should also undergo effective assessment and obtain the corresponding certificate of qualification. Only certified personnel can issue calibration certificates and calibration reports, and only such certificates and reports are considered valid.