The paper describes an automatic tuning method for the design of PID controllers. Its starting point is the requirement for accurate modelling of process deadtime which is calculated from a discrete model description of the process. Controller design is achieved by a combination of pole-zero cancellation and frequency-response methods which ensures that the system exhibits favourable gain and phase characteristics and good relative stability even for processes with large deadtime. Results are presented for the control of a steam/water heat exchanger and illustrates the usefulness of this technique.
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