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A PID controller is used to control the temperature of a
Chapter 12, Problem 12.11(choose chapter or problem)
A PID controller is used to control the temperature of a jacketed batch reactor by adjusting the flow rate of coolant to the jacket. The temperature controller has been tuned to provide satisfactory control at the nominal operating conditions. Would you anticipate that the temperature controller may have to be retuned for any of the following instrumentation changes? Justify your answers. (a) The span of the temperature transmitter is reduced from 30 to 15 oc. (b) The zero of the temperature transmitter is increased from 50 to 60 C. (c) The control valve "trim" is changed from linear to equal percentage. (d) The temperature of the coolant leaving the jacket is used as the controlled variable instead of the temperature in the reactor.
Questions & Answers
QUESTION:
A PID controller is used to control the temperature of a jacketed batch reactor by adjusting the flow rate of coolant to the jacket. The temperature controller has been tuned to provide satisfactory control at the nominal operating conditions. Would you anticipate that the temperature controller may have to be retuned for any of the following instrumentation changes? Justify your answers. (a) The span of the temperature transmitter is reduced from 30 to 15 oc. (b) The zero of the temperature transmitter is increased from 50 to 60 C. (c) The control valve "trim" is changed from linear to equal percentage. (d) The temperature of the coolant leaving the jacket is used as the controlled variable instead of the temperature in the reactor.
ANSWER:Step 1 of 3
The standard transfer function of the feedback control system is given by,
…… (1)
Therefore, the standard characteristics equation is,
…… (2)
The PID controller which is used to control the temperature, have to retuned only if any of the blocks among , , , and has change the values.