This set of Flexible Manufacturing System Multiple Choice Questions & Answers (MCQs) focuses on “Programmable Logic Controllers”.
1. What is meant by PLC?
a) Programmable Ladder Controller
b) Programmable Logic Controller
c) Protected Logic Controller
d) Protected Ladder Controller
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Explanation: PLC means Programmable Logic Controller. It is controller which is microcomputer sized used to perform the instructions in the form of program. It has a separate memory space allocated to store the programs.
2. Who coined the term PLC?
a) Charles Babbage
b) Charles Dickens
c) Allen Border
d) Allen Bradley
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Explanation: Allen Bradley coined the term Programmable Logic Controller. He was one of the leading Programmable Logic Controller suppliers in the early 1980’s. PLC’s are widely used in paper mill operations, automotive industries and chemical processing.
3. Programmable Logic Controllers cannot be reprogrammed.
a) True
b) False
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Explanation: Reprogramming is one of the specialized features of Programmable Logic Controllers. The conventional controllers must be rewired and will be scrapped for further use. PLC’s are easier when compared to wiring the relay controllers.
4. Which of the following is the central processing unit of PLC?
a) I/O Module
b) Processor
c) Memory Unit
d) Power Supply
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Explanation: The Central Processing Unit of Programmable Logic Controllers is the Processor. In order to determine the appropriate output signals, various logic and sequential control functions are executed by the processor based on the inputs.
5. Which of the following contains programs in order to instructions to the control Unit?
a) Memory Unit
b) Input Module
c) Output Module
d) Power Supply
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Explanation: Memory Unit contains the instructions to activate the PLC’s in the form of programs. It will include programs of logical sequencing and Input/output operations. These can be edited and replaced by the PLC user.
6. How much of power is required to drive the Programmable Logic Controller?
a) 0 VAC
b) 120 VAC
c) 50 VAC
d) 75 VAC
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Explanation: In order to drive the Programmable Logic Controller, a power supply of 120 VAC is typically required. Some of the heavy engineering applications use upto maximum of 240 VAC to drive the Programmable Logic Controllers.
7. Which of the following includes battery back up in order to support external power failure?
a) Back up Module
b) Output Module
c) Input Module
d) Power Supply Unit
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Explanation: In order to support the Programmable Logic Controllers during any external power failure, a battery backup will be provided. It can be used to switch on the Programmable Logic Controllers automatically in the absence of power.
8. Power Supply Unit converts the input signal into alternating current voltages.
a) True
b) False
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Explanation: Power Supply Unit converts the input signal of 120 VAC into direct current voltages. The Converted voltage will be typically ±5V. The converted low output voltages will be used to operate the equipment.
9. Which of the following provides the connections to the equipment to be controlled?
a) Relay
b) Input/ Output Module
c) Power Supply Unit
d) Moderator
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Explanation: To control the processing equipments using the Programmable Logic Controllers, Input/ Output modules are connected to it. The controller inputs will be the signals from push buttons, limit switches whereas output will be to ON/OFF the equipments.
10. How is the size of the PLC determined?
a) Number of terminals
b) Power Supply
c) Memory Unit
d) Size of Relay
View Answer
Explanation: The Number of terminals determines the size of the given Programmable Logic Controller. Greater the number of Input or Output terminals, larger will be the size of the Programmable Logic Controllers.
More MCQs on PLC:
Sanfoundry Global Education & Learning Series – Flexible Manufacturing System.
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