Closed-loop performance monitoring using loop tuning

In this article it is shown how the tuning of a loop is used to commission a closed-loop performance monitoring method. The extended prediction horizon index is used to monitor disturbance rejection properties expressed with the impulse response. The impulse response is obtained from the tuning of the loop. All parameters of the monitoring method are set by using the impulse response. The presented method works equally well when disturbances are stochastic or deterministic. It is shown how typical performance problems are detected by the method. Simple rules of thumb to commission the method for lambda-tuned loops are given. Finally an industrial evaluation is presented for 18 lambda-tuned loops from a pulp and paper mill.