Top 10 Multiple choice questions on Programmable logic controller

Question 1: The PLC was invented by.

  • Bill Gates
  • Dick Morley
  • Bill Landis
  • Tod Cunningham

Answer: Dick Morley

Question 2: The first company to build PLCs was.

  • General Motors
  • Allen Bradley
  • Square D
  • Modicon

Answer: Modicon

Question 3: Which part of plc monitors the inputs and makes decisions in a PLC.

  • Sensor
  • CPU
  • Input Module
  • Output Module

Answer: CPU

Question 4: One of the following is an input device.

  • Motor
  • Light
  • Valve
  • Sensor

Answer: Sensor

Question 5: Which one of the following is not a PLC manufacturer.

  • Siemens
  • Mitsubishi
  • Microsoft
  • ABB

Answer: Microsoft

Question 6: Solenoids, lamps, motors are connected to:

  • Analog output
  • Digital output
  • Analog input
  • Digital input

Answer: Digital output

Question 7: In a PLC “I” is used for output and “Q” is used for input.

  • True
  • False
  • None of the above

Answer: False

Question 8: To increase the number of inputs and outputs of the PLC, one can use expansion modules.

  • True
  • False
  • None of the above

Answer: True

Question 9: An example of discrete (digital) control is:

  • Varying the volume of a music system
  • Turning a lamp ON or OFF
  • Varying the brightness of a lamp
  • Controlling the speed of a fan

Answer: Turning a lamp ON or OFF

Question 10: Which of the following statements is NOT correct?

  • The status of each input can be checked from one location and outputs can be forced on and off.
  • All symbols in the RLL represent actual components and contacts present in the control system.
  • PLCs are not as reliable as electromechanical relays in RLL.
  • Input (-| |-) and output (- ( ) -) instruction symbols in the ladder logic represent only data values stored in PLC memory.

Answer: PLCs are not as reliable as electromechanical relays in RLL.


Leave a Reply

Your email address will not be published.