Methods for determining the recalibration intervals of measuring equipment during their operation

The article shows that at the request of international regulations on the establishment of inter-calibration intervals for measuring equipment during operation, it is proposed to conduct current intermediate checks. In order to detect early the characteristics of measuring equipment beyond the allowable limits, a method of sliding regression is proposed, based on the use of CUSUM-chart, which allows you to quickly and accurately determine the area of process changes and the time when corrective action is required. It is shown that in order to avoid erroneous decisions about the state of measuring equipment, only the traditional control of the drift of the mean value of the controlled characteristic is not enough, it is necessary to control the standard deviation of the observation results. For this purpose, additional criteria based on Pearson's distribution with the establishment of a critical sequence of standard deviation points are introduced. To detect a change in metrological characteristics, an adaptive algorithm for detecting a critical sequence of standard deviation points is proposed. Intermediate checks shall be carried out until a situation arises where in one of the ranges (or combinations thereof) has been hit by two standard deviations points in succession.