COMPARING AND TUNING PI AND PID DIGITAL CONTROL ALGORITHMS.
LOUISIANA STATE UNIV BATON ROUGE COLL OF ENGINEERING
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For years engineers have followed the practice of installing proportional-plus-integral PI controllers in the normal control loops and proportional-plus-integral-plus-derivative PID controllers in the tough control loops--usually slow loops involving temperature. The typical reason given is that the additional cost of the derivative mode could only be justified in difficult control loops. Another reason is that the PID controller is much more difficult to tune, and engineers would prefer not to undertake it unless necessary. With the advent of direct digital control systems, the increased cost of using a PID algorithm instead of a PI algorithm is negligible, and only the tuning problem remains. Perhaps automated tuning procedures will be perfected in the future to eliminate this problem, but for the present, some guidelines are needed for determining when and how PID and PI algorithms should be used. This report attempts to answer some of these questions about PI and PID algorithms. Author
- Statistics and Probability
- Test Facilities, Equipment and Methods