Calibration and Verification of Measuring Instruments: Conceptual Transformation

The present article discusses problems associated with the calibration of measuring instruments (MIs). The author gives a brief review of the 1978–1992 discussion on problems related to the applicability of statistical methods, along with providing an insight into the transformation of calibration concepts according to regulatory documents. The general measurement problem of testing for type approval purposes, as well as MI verification and calibration, is considered as an issue concerning the identification of functional metrological characteristics. It is noted that MI calibration for operating conditions is of great importance during verification under normal conditions. The main difficulty in solving this problem is found to be the multidimensionality of the calibration function model and the need to take into account inadequacy-related errors along with measurement errors. It is shown that if only one of these components is factored in, the model may become unnecessarily complex with a loss of stability, or it could lead to the use of incomplete models of the calibration function giving the impression of high accuracy. Finally, the author provides an example of MI calibration for operating conditions using two influence quantities.