MONITORING THE CALIBRATION STATUS OF A MEASURING INSTRUMENT BY A STOCHASTIC-MODEL

The paper discusses a class of stochastic models for evaluating the op timal calibration interval in measuring instruments, The model is base d on the assumption that the calibration status of a measuring instrum ent can be monitored by means of one observable parameter, The observa ble parameter is undergoing a stochastic drift process, The paper intr oduces and compares stochastic drift models of different nature, and e stimates the first passage time of the monitored parameter on a preset limit, The calibration interval is determined as a suitable percentil e of the distribution function of the first passage time, A preliminar y validation of the model, based on a sample of experimental data coll ected on a class of instruments, is finally reported.