Tuning of PID controller parameters for a new process is a challenge and of great concern to process control engineers. Developing and implementing an inexpensive device along with programs for on-line instant evaluation of tuning criteria benefit students in the process control laboratory experiments. A simple circuit to turn on/off an electric bulb or electric heater can be used for real-time tuning. The initial controller setting of three key controller parameters [proportional gain (K{sub}C), integral time constant (τ{sub}I), and derivative time constant (τ{sub}D)] can be computed using the major tuning approaches such as Ziegler-Nichols, Cohen-Coon and Tyreus-Luyben methods. The robustness of the tuned parameters has been tested for a disturbance in the set point as well as in the process. Each of these disturbances is illustrated graphically to demonstrate its performance. This approach provided students an instant quantitative guideline as to how good these tuning methods are for a given process.
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