Autotuning and monitoring

With reference to single-input single output classical control structures, we illustrate two deterministic approaches to monitoring. On line closed loop relay tests are proposed for monitoring performance of the controlled plant and for an on-line autotuning of the controller parameters, based on the integral of the absolute value of the error (IAE). With respect to standard formulation, a modified IAE index is used, computed from the data collected during a period of the output of the process, executing the auto-tuning test, without substantial modifications of the operating point