According to its measurement principle, the following points must be observed in order to obtain accurate and reliable measurement data:
First, the performance indicators of the instrument must meet the requirements of the national metrological verification regulations. The instrument in use must undergo periodic verification. When necessary (instrument is used frequently or in a critical state of qualification), an intermediate self-inspection is required to determine its metrological performance and the coefficient error is within the allowable range. Otherwise, accurate data cannot be obtained.