PROCESS CONTROL Flashcards
1
Q
- A Direct Acting controller defines the error as e = SP – PV?
a. True
b. False
A
b. False
2
Q
- A controller is in AUTO which statement is true?
a. The loop is closed
b. The SP is 50%
c. The manipulated variable is changing in response to the controlled variable
d. The loop is open
A
a. The loop is closed
3
Q
- In order to achieve negative feedback:
a. The controller output must match the process and measurement variable
b. The process variable must subtract from the measurement variable
c. The controller output must increase with an increase in process variable
d. The controller output must be such as to oppose the change in the process variable
A
D. The controller output must be such as to oppose the change in the process variable
4
Q
- The type of response which is as fast as possible without overshoot?
a. Marginally damped
b. Under damped
c. Critically damped
d. ¼ Amplitude decay
A
c. Critically damped
5
Q
- Controller Bias is :
a. Controller setpoint with no error
b. Controller feedback trim
c. Controller error
d. Controller output with no error
A
d. Controller output with no error
6
Q
- Which of the following controllers have Manual Bias:
a. P-only
b. PI
c. PD
d. PID
A
a. P-only
7
Q
- The output of a controller decreases from 12 psi to 6 psi due to a measurement signal (PV) increase from 8 psi to 10 psi. Which of the following is true?
a. RA with Kc = 0.3
b. RA with Kc = 3.0
c. DA with Kc = 0.3
d. DA with Kc = 3.0
A
A. RA with Kc = 3.0
8
Q
- On what does the output of a P-only controller depend?
a. The magnitude, sign and duration of the error
b. The magnitude and sign of the error
c. The rate of change of the error
d. The duration and rate of change of the error
A
b. The magnitude and sign of the error
8
Q
- The output of a PI controller depends upon on what?
a. The magnitude , sign and duration of the error
b. The magnitude and sign of the error
c. The rate of change of error
d. All of the above
A
a. The magnitude , sign and duration of the error
9
Q
- What is the controller output change if a 5% error is on a reverse acting proportional controller with a 50% PB?
a. 10%
b. 40%
c. 25%
d. 2.5%
A
a. 10%
9
Q
- A PI controller has an integral time of 0.25 min/repeat. What is the integral rate?
a. 4 repeats/minute
b. 4 minutes/repeat
c. 0.25 repeats/minute
d. 0.25 minutes/repeat
A
a. 4 repeats/minute
10
Q
- What is the gain (Kc) of a controller which has a proportional band of 20%?
a. 2.0
b. 0.5
c. 1.0
d. 5.0
A
d. 5.0
11
Q
- What is the effect of adding Integral action on a process:
a. stability increases
b. offset increases
c. deadtime decreases
d. offset is eliminated
A
d. offset is eliminated
12
Q
- Reset Windup can be prevented in a pneumatic PI controller by:
a. Detuning the control loop
b. Adjusting the manual output regulator
c. Adding a derivative filter
d. Restricting the magnitude the controllers bias can accumulate to
A
d. Restricting the magnitude the controllers bias can accumulate to
13
Q
- Determine the Correct Controller Action for the following P&ID diagram if the FCE = Fail Closed :
a. Direct Acting
b. Reverse Acting
A
a. Direct Acting
14
Q
- Which of the following can cause non-linearity in a control loop?
a. Final Control Element
b. Process
c. Transmitter
d. All of the above
A
d. All of the above
15
Q
- A non linear control loop
a. Provides the same control at any operating point
b. PID Controller gives good control at all operating points
c. Process Gain changes at different operating points
d. Proportional gain changes at different operating points
A
c. Process Gain changes at different operating points
16
Q
- To negate the effects of non-linearity:
a. Use a multipoint characterizer to linearize the loop
b. Tune the control loop at the normal operating point
c. Use a cascade controller
d. Use a linear control valve
A
a. Use a multipoint characterizer to linearize the loop
17
Q
- A load disturbance:
a. Can change the inherent valve characteristics
b. Should be tuned for PID Control
c. Can change the Process Transfer function
d. Results in offset
A
c. Can change the Process Transfer function