AN EXPERT-SYSTEM FOR CONTROL LOOP PERFORMANCE

The performance of process control loops often deteriorates over time. If the relative change in this performance could be quantified, maint enance of control loop elements could be carried out before quality an d efficiency are severely affected. This paper mill details the develo pment of an expert system designed to monitor control performance in a newsprint mill. The expert system directs the sampling of data from t he mill's control loops, verifies the validity of the data and quantif ies the loop's performance using a normalized performance index.