PLANT-WIDE FEEDBACK-CONTROL PERFORMANCE ASSESSMENT USING AN EXPERT-SYSTEM FRAMEWORK

There are many applications where multivariate control schemes are jus tified from an economic and quality improvement standpoint. Neverthele ss, single-input single-output (SISO) and multi-input single-output (M ISO) controllers remain the most commonly used controllers in process applications. This paper reviews SISO control performance assessment a nd details the development of an expert system that quantifies control loop performance on an on-going basis. The expert system schedules ea ch of a newsprint mill's control loops for analysis, directs the sampl ing of data, verifies the validity of the data, and quantifies the loo p's performance using a normalized performance index.