This document contains 31 multiple choice questions related to control systems and controllers. The questions cover topics such as: - The relationship between steady-state error, gain, and oscillations for proportional controllers. - Design criteria for PID controllers including quarter-amplitude decay ratio and Zeigler-Nichols method. - Phenomena related to switching between manual and automatic modes. - Definitions of proportional band, proportional gain, reset control, and integral control. - Applications and effects of P, PI, PD, and PID controllers. - Characteristics and uses of proportional, integral, and derivative controllers. The document concludes by providing the solutions to each multiple choice question.

1. Assistant Prof. Dr. Khalaf S Gaeid
Electrical Engineering Department/Tikrit University
khalafgaeid@tu.edu.iq
gaeidkhalaf@gmail.com
+9647703057076
April 2018

2. 1. What is the relationship between the steady-state error, gain and
the tendency of oscillations when the controller is supposed to be
under the proportional action?
a) Steady-state error increases with an increase in gain and oscillation
tendency
b) Steady-state error decreases with the decrease in gain and oscillation
tendency
c) Steady-state error decreases with an increase in gain and oscillation
tendency
d) Steady-state error increases with the decrease in gain and oscillation
tendency

3. 2. The quarter-amplitude decay ratio is basically a design criteria
specified by Zeigler-Nichols method implies that the amplitude of an
oscillation must be reduced by a factor of __________
a) four over a whole period
b) four over an half period
c) four over a quarter period
d) four over a quarter and a half period

4. 3. Which phenomenon occurs due to coincidence of two output
signals generated manually as well as by control algorithm at the
time of switching in manual mode ?
a) Bumped Data Transfer
b) Bumpless Transfer
c) Coincidence Data Transfer
d) None of the above

5. 4. Proportional band of a controller is defined as the range of:
a)Measured variable to the set variable
b)Air output as the measured variable varies from maximum to minimum
c) Measured variables through which the air output varies from
maximum to minimum
d) None of the above

6. 5. Proportional band of the controller is expressed as:
a) Gain
b) Ratio
c) Percentage
d) Range of control variables

7. 6. The term reset control refers to:
a) Proportional
b) Integral
c) Derivative
d) None of the above

8. 7. The integral control:
a) Increases the steady state error
b) Decreases the steady state error
c) Increases the noise and stability
d) Decreases the damping coefficient

9. 8. proportional gain for PID controller is more than the PI control.
a) Leads to destabilizing effect
b) Leads to stabilizing effect
c) No action is taken
d) All the above.

10. 9. For PI control use a lower proportional gain because the pressure
of the integral control mode introduces additional _____ in all the
frequencies.
a)Phase lead
b) Phase lag
c) Both (a) & (c)
d) None of the above

11. 10. The presence of the derivative control mode introduces ______
with strong ______ in the closed loop response.
a) Phase lag and destabilizing effect
b) Phase lead and stabilizing effect
c) Phase lag and stabilizing effect
d) Phase lead and destabilizing effect

12. 11. Ziegler Nichols method is also called as _______
a) Open loop transient response method
b) Frequency response method
c) Damped oscillation method
d) Ultimate cycling method
12. For proportional control the steady state error (offset) tends to
Zero when Kp is:
a) Infinity
b) Zero
c) One
d) 0.5

13. 13. Use of I-control along with P-control facilitates
a) elimination of offset
b) reduction of offset
c) reduction of stability time
d) none of these.
14.Reset rate is the another term used for __________ time.
a) Dead
b) Integral
c) Derivative
d) none of these
15. Proportional + integral is used to have _______ of the process
a) Slow response
b) Fast response
c) Low peak overshoot
d) Reduced oscillation

14. 16. Which type of controller increases the stability of the system by
keeping it at a consistent setting?
a) Derivative
b) Proportional
c) ON OFF controller
d) Integral
17.PID controller is also known as
a)two term controller
b)three term controller
c)four term controller
d)proportional controller

15. 18-The control system design specification for a chemical process is
described as short settling time, improved damping and zero steady
state error. What control do we choose?
a) P
b) PI
c) ID
d) PID
19. Which of the following controllers has the least maximum
deviation ?
a) P-I controller
b) P-D controller
c) P-controller
d) P-I-D controller

16. 20. Which of the following controllers has maximum offset ?
a) P-controller
b) P-I controller
c) P-I-D controller
d) P-D controller
21.Proportional (P) Controller is Used
a)Load Changes are small
b) Offset can be tolerated
c) Permit a narrow proportional band
d)Reduce the amount of the offset
e) All above
22.Integral (I) Controller is Used:
a) offset must be eliminated
b) Integral saturation due to sustained deviation is not objectionable
c) Reduce overshoot
d) All above

17. 23. Proportional and Integral action is employed when
a) System changes is small
b) Offset must be eliminated
c)No objection on the recovery duration
d) All above
24. PD action is employed when
a) When the system changes are small
b) Improve the recovery time
c)When system lags are high
d) All above
25.PID controller is used when system requires
a)System changes are small
b)Offset must be eliminated
c)Fast recovery time
d) All above

18. 26.Proportional (P) Controller is Used(correct if its not)
a)small change Rise time
b)Decrease settling time
c)Decrease overshoot
d)No change in SSE
e)None of the above(this is Derivative )
f)All the above
27.Derivative (D) Controller is Used(correct if its not)
a)Decrease the rise time
b)Increase the settling time
c)Increase the overshoot
d)Eliminate the SSE
e)None of the above(this is integral)
f)All the above

19. 28.Integral (I) Controller is Used(correct if its not)
a)Decrease the rise time
b)Small change in the settling time
c)Increase the overshoot
d)Decrease the SSE
e)None of the above(this is proportional)
f)All the above
29. Effect of PD which is (Phase Lead Compensation) are:
a) Gain crossover frequency increases.
b) Bandwidth decreases.
c) Phase margin will be increase.
d) Response will be slower before due to decreasing bandwidth, the rise
time and the settling time become larger.
e) None of the above

20. 30. Effect of Phase Lead Compensation(PD controller)
a) The velocity constant Kv increases.
b) The slope of the magnitude plot reduces at the gain crossover
frequency so that relative stability improves and error decrease due to
error is directly proportional to the slope.
c) Phase margin increases.
d) Response become faster.
e) None of the above
f)All the above
31. Addition of zeros in transfer function causes which of the
following ?
(a)Lead-compensation
(b)Lag-compensation
(c)Lead-lag compensation
(d)None of the above

21. Solutions
1.c
2.a
3.b
4.c
5.c
6.b
7.b
8.b
9.b
10.b
11.d
12.a
13.a
14.b
15.a
16.b
17.b
18.d
19.b
20.a
21.e
22.d
23.d
24.d
25.d
26.e_(this is Derivative )
27.e_(this is integral)
28.e_(this is
proportional)
29.e
30.f
31.b