A water tank heating process shown in Fig. E16.4 controls the outlet temperature at a desired set
Question:
(a) Assuming that a PI controller with ÏI = 0.2 min is used, find the range of Kc values for which the system is stable for a standard single control loop configuration.
(b) Suppose a cascade control strategy is implemented to handle variations in upstream steam pressure. How should the second loop be confgured? Draw the block diagram for the process using this strategy and label the process variables.
(c) For the ï¬owrate measurement, Gm = 0.4, and an inner loop proportional controller, compare the cascade controller closed-loop response with that of the standard PI controller (Kc1 = 2 and ÏI1 = 5) for a unit step disturbance in steam pressure. For the cascade controller, use Kc1 = 2, ÏI1 = 5, and K c2 = 2.
Step by Step Answer:
Process Dynamics and Control
ISBN: 978-1119385561
4th edition
Authors: Dale E. Seborg, Thomas F. Edgar, Duncan A. Mellichamp, Francis J. Doyle