Practical approaches to traditional and predictive control loop tuning

It is well known that many complex industrial processes are often satisfactorily controlled by means of simple three term (PID) controllers. However, for those processes which use PID loops the task of `tuning´ can be a very time consuming and expensive operation. Consequently any help offered to the process operator to ease this tedious task and at the same time produce consistent behaviour is very desirable. The first part of the presentation will be used to demonstrate the MASTERTUNE package which automatically determines the necessary PID parameters and then when prompted downloads the values into a commercial process controller (in this case the TCS 6350 system). An exciting recent trend in industrial control permits the end user to implement customised control strategies rather than being constrained to PID structures. The second part of this presentation will concentrate on the PRODESIGN package which provides a complete design environment allowing the user to implement advanced control strategies where needed. It is well recorded that for systems with large time delays and/or nonminimum phase behaviour conventional PI(D) control normally results in a sluggish oscillatory response. Much better performance can be achieved by the new `predictive´ control algorithms. The strategy to be described here is the PIP or PI Plus algorithm