Control Loops Multiple Choice Questions

1. The most common analog signal standard for industrial process instruments is 4 to 20 _________
a) milliamps DC
b) amps AC
c) volts
d) milliamps
Answer: milliamps DC
2. Which of the following is not a “final control element”?
a) A pressure transmitter
b) An electric motor
c) A heating element
d) A control valve
Answer : A pressure transmitter
3. Identify which of the following is an example of a “primary sensing element” 
a) I/P transducer
b) Instrument signal cable
c) Control valve
d) Diaphragm
Answer : Diaphragm
4. A basic control loop will consist of __________
a) signal converter, resistor, knob, and control valve
b) transducer, valve packing, hex-head wrench, and tubing
c) transmitter, controller, I/P transducer, and control valve
d) resistor, capacitor, terminal block, and battery
Answer : transmitter, controller, I/P transducer, and control valve
6. The purpose of a “shield” wire on an instrument signal cable is to __________
a) Hold a steadier setpoint value
b) Ensure technician safety
c) Minimize electrical noise
d) Protect the cable from corrosion
Answer : Minimize electrical noise
7. In a process controller, “output” refers to
a) The target value for the measured variable
b) The DC supply power to the transmitter
c) The maximum value for the low-alarm point
d) The command signal to the control valve
Answer : The command signal to the control valve
8. When a process controller is in the “automatic” mode, __________
a) The output responds to changes in the process variable
b) The control valve will fail closed
c) The process variable cannot deviate from setpoint
d) The controller will automatically generate alarms
Answer : The output responds to changes in the process variable
9. Which of the following is a “final control element”?
a) A pressure transmitter
b) An electric motor
c) A control valve
d) Both b and c
Answer: Both b and c
10. The most common analog signal standard for industrial process instruments is __________
a) 4 to 20 milliamps DC
b) 0 to 5 amps AC
c) 0 to 10 volts
d) 0 to 20 milliamps
Answer : 4 to 20 milliamps DC
11. In order for a control loop to work well under a wide range of conditions, it must possess _________
a) Calibration drift
b) Hysteresis
c) A very expensive transmitter
d) Negative feedback
Answer : Negative feedback
12. A basic control loop will consist of _________
a) Transmitter
b) Controller
c) I/P transducer
d) All of the mentioned
Answer: All of the mentioned
13. In a home heating system, room temperature is the _________
a) Process variable
b) Setpoint
c) Inferred variable
d) Manipulated variable
Answer : Process variable
14. In a home heating system, room temperature is the Manipulated variable.
a) True
b) False
Answer: True
15. pressure transmitter is a final control element.
a) True
b) False
Answer: False