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Programmable Logic Controller Questions and Answers

Refer the below Programmable Logic Controller Questions and Answers which are useful for the exam preparation.

Programmable Logic Controller Questions

Programmable Logic Controller Questions

1. A switch or a pushbutton is a ________ input.

2. A lamp or a solenoid is an example of a ______ output.

3. The ____________ makes decisions and executes control instructions based on the input signals.

4. _________ _________ is a PLC programming language that uses components resembling elements used in a line diagram.

5. A _________ consists of one or more instructions that accomplish a task.

6. Memory is divided into three areas: _________ , _________ , and ________ _________ space.

7. When talking about computer or PLC memory, 1K refers to _________ bits, bytes, or words.

8. Software that is placed in hardware is called _________ .

9. Which of the following is not required when creating or changing a PLC program?

a. PLC
b. Programming Device
c. Programming Software
d. Connector Cable
e. Printer

10. A special cable, referred to as a _______ cable, is needed when a personal computer is used as a programming device.

11. Label the following statements as TRUE or FALSE.

11.a) Most PLCs have a fixed number of timers

11.b) Normally closed contacts “invert” the state of the signal they reference

11.c) PLCs are advantageous for use in fixed-circuit or fixed program operations

12. Complete the following statements.

12.a) PLC process scanning consists of the ____ scan, ____ scan and ____ scan.

12.b) ____ scanning and ____ scanning are the two methods (orders) in which PLCs solve ladder logic programs.

13. Describe the differences between an [XIC] and an [OSR] instruction.

14. Label the following statements as TRUE or FALSE.

14.a) PLC scan time is dependent on the complexity of the PLC program

14.b) Most PLC timers have microsecond resolution

Also Read : PLC Program for Analog Input Sampling

Answers :

1) discrete;

2) discrete;

3) CPU;

4) Ladder logic;

5) program;

6) program, data, configuarable parameter;

7) 1024;

8) firmware;

9) e;

10) PC/PPI.

11.a ) FALSE

11.b ) TRUE

11.c ) FALSE



13. An [XIC] (examine if closed) instruction is used in a ladder logic program to determine if a bit is on (1). When the instruction is executed, if the bit addressed is on (1), then the instruction is evaluated as TRUE.

When the instruction is executed, if the bit addressed is off (0), then the instruction is evaluated as FALSE. The [OSR] (one shot rising) instruction is true for one PLC scan when the rung conditions preceding the OSR go from false-to-true.

14.a) TRUE

14.b) FALSE

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