What are the similarities and differences between calibration and verification?

The fundamental difference between verification and calibration is that the former is the verification process from top to bottom, for the law, with mandatory, and metrological verification must be carried out metrological verification procedures; the latter is the comparison of the chain from bottom to top, the user according to the need to trace back to the freedom to voluntarily select the calibration organization, calibration project, measurement range and calibration time interval. The main purpose of the calibration work is to determine or confirm whether the measuring instrument meets the statutory requirements, while the main purpose of the calibration is to determine the value of the measuring instrument and measurement uncertainty. Therefore, the calibration conditions, scope and procedures, often only with the measurement of characteristics related to the general provisions and requirements, unlike the verification, both measurement technology requirements and management of the legal system requirements. Measurement of the scope of calibration is in addition to the mandatory verification of other measuring instruments. Calibration and verification of the similarities and differences between the project calibration verification purpose of the law to ensure the accuracy and reliability of the value of the measurement standard traceable to national or international benchmarks characteristics of the market services legal system management management mode voluntary mandatory object in addition to the verification of measuring instruments other than the mandatory inspection of measuring instruments measuring instruments and measurement standards pathway bottom-up traceability top-down transmission range of the community in a certain place or system of technical basis of the calibration specification calibration protocols conclusions Give the calibration results and measurement uncertainty to determine whether qualified