What does metrological calibration mean?

Calibration refers to a set of operations to determine the relationship between the indicated value of measuring instruments and the complex present value of corresponding measuring standards under specified conditions. Calibration is a way to trace the source of value transmission. The calibration scope mainly refers to the non-compulsory verification of measuring instruments specified in the Catalogue of Measuring Instruments Managed by Law in People's Republic of China (PRC). The calibration basis should give priority to the national calibration standard. If there is no national calibration standard, the calibration technical conditions can be compiled according to the metrological verification regulations or related product standards, operating instructions and other technical documents, and can only be used after being approved by the technical director of the technical institution. Calibration only gives data or curves that deviate from their indicated values, but it is not necessary to judge whether the instrument is qualified. Calibration should also have a calibration period.