Question

It is required to control the volume of the contents in the jacketed reactor shown in the figure. 
 

Which one of the following schemes can be used for feedback control? 
 

• A. Measure L101 and manipulate valve V-2
• B. Measure T101 and manipulate valve V-1
• C. Measure L101 and manipulate valve V-3
• D. Measure F101 and manipulate valve V-1

Hint:

In feedback control, always measure the controlled variable and manipulate the actuator or valve that adjusts that variable.

Answer 1

The Correct Option is C

In a feedback control system, the measurement of a controlled variable (in this case, liquid level) is used to manipulate a valve to regulate the system.

Step 1: Identify the controlled variable.
Here, the liquid level is controlled, which is measured by L101.

Step 2: Identify the manipulated variable.
The manipulated variable is V-2, which controls the inflow into the reactor, adjusting the volume.

Step 3: Conclusion.
Therefore, the correct feedback control scheme involves measuring L101 and manipulating valve V-2.