Anna University, B E Mechatronics Engineering, Vi Semester Programmable Logic Control


Programmable Logic Control



TIME – 3 Hours

MAXIMUM : 100 Marks

PART – A   (10 x 2 = 20 Marks)




1. What would happen if we did not use XOR approach in PAL ?

2. What is PGA and the way by which the user can realize the function for programming ?

3. What are the three major types of PLC application ?

4. Name the two ways in which I/O is incorporated in to the PLC

5. EPROM is otherwise known as ? Does it require battery back up ?

6. Draw the relay schematic and ladder logic program fro AND gate logic ?

7. Write the process of a program scanning for the operation cycle ?

8. Write any two types of manually operated switches ?

9. Draw a off delay timer circuit and timing diagram for (NOTO) ?

10. List any four types of DATA COMPARE INSTRUCTION ?


PART – B                           (5 x 16 = 80 Marks)


11. Design a sequential traffic light controller for the intersection of the street “A” and the street “B” using 22V10. Each street has traffic sensors which detect the presence of the vehicle or stopped at the intersection ?


12. (a) Explain in detail about the memory design and memory types of the PLC?


( OR )


(b) (i) Write a note on analog I/O modules ?                                               (4)

(ii) List the types of special I/O modules and explain them briefly ?  (12)


13. (a) Draw a ladder logic program for

(i) Multiple timers using the greater than or equal to instruction ?                 (8)

(ii) Get / less than data compare statements ?                                        (8)


( OR )

(b)   Explain about the up/down counter with ladder logic diagram and

timing diagram ?                                                                                       (16)


14. a) Explain in detail about any four types of program control instructions With necessary diagrams ?                                                                         (16)

( OR )

b) Explain in detail about four basic type of the math instructions ?               (16)


15. a) Two conveyor feed a main conveyor the count from each feeder

Conveyor is fed in to an input register in the PLC. Construct a PLC

Program to obtain the total count of parts in the main conveyor. If

The total count of main conveyor reaches 15, stop the conveyor?  (16)


( OR )


b)    Construct a PLC ladder diagram for a spray painting application; after a count of 15 from a sensor, a paint spray is to run for 25 seconds.        (16)

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