# PID Controller

1. In a proportional temperature controller, if the quantity under the heater increases the offset will:
a) Increase
b) Reduce
c) Remain uneffected
d) None of the above
2. The term reset control refers to:
a) Proportional
b) Integral
c) Derivative
d) None of the above
3. In a PID controller, the overshoots has increased. The derivative time constant has to be __ so as to reduce the overshoots:
a) Increased
b) Reduced
c) Reduced to zero
d) None of the above
4. Proportional band of the controller is expressed as:
a) Gain
b) Ratio
c) Percentage
d) Range of control variables
5. When derivative action is included in a proportional controller, the proportional band:
a) Increases
b) Reduces
c) Remains unchanged
d) None of the above
6. 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
Answer: Measured variables through which the air output varies from maximum to minimum
7. Which of the following system provides excellent transient and steady state response:
a) Proportional action
b) Proportional + Integral action
c) Proportional + Differential action
d) Proportional + Integral + Differential action
Answer: Proportional + Integral + Differential action
8. In a PID controller, the offset has increased. The integral time constant has to be ___ so as to reduce offset:
a) Reduced
b) Increased
c) Reduced to zero
d) None of the above
9. 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
10. The number of operational amplifiers require for designing of electronic PID controller is:
a) 1
b) 2
c) 3
d) 6