# PTU B.Tech ECE 6th Semester May 2019 58040 PROGRAMMABLE LOGIC CONTROLLERS and APPLICATIONS Question Papers

PTU Punjab Technical University B-Tech May 2019 Question Papers 6th Semester Electronic and Communication Engineering (ECE)

Roll No.
Total No. of Pages : 02
Total No. of Questions : 09
B.Tech.(EIE) (2011 & Onwards E-I) (Sem.?6)
PROGRAMMABLE LOGIC CONTROLLERS & APPLICATIONS
Subject Code : EI-310/DE-1.5
M.Code : 58040
Time : 3 Hrs. Max. Marks : 60
INSTRUCTION TO CANDIDATES :
1.
SECTION-A is COMPULSORY consisting of TEN questions carrying T WO marks
each.
2.
SECTION-B contains FIVE questions carrying FIVE marks each and students
have to attempt any FOUR questions.
3.
SECTION-C contains T HREE questions carrying T EN marks each and students
have to attempt any T WO questions.

SECTION-A

a) Differentiate between a PLC and a personal computer.

b) The programmable controller operates in a real time. What does this mean?

c) What are the most important factors in selecting the size of a PLC?

d) What is the function of watchdog timer in a PLC?

e) Name any four input and output devices suitable for the input and the output modules.

f) What determines the maximum speed of transitions that a PLC counter can count?
Why?

g) What are the disadvantages of a PLC?

h) What is the function of the internal control relay?

i) What is a drum sequencer?

j) Why do PLCs execute memory checking routines?

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SECTION-B
Q2. Explain the scan cycle of a PLC.

Q3. Write the ladder programs for the NAND, NOR and XOR logic functions.
Q4. Draw the schematic diagram of the dc input module and explain each section.

Q5. Develop a sequencer control system to operate a basic two-axis robo.
Q6. Explain the various timers and counters available in a PLC.

SECTION-C
Q7 a) Explain the memory organization of a PLC. Name the different types of data files.
5

b) Make a sequential function chart and write a ladder program for following the operation
of a start switch (S1), after which the tank is filled by opening a valve ( V1) until a level
switch (L1) is triggered, then the tank is drained by opening drain valve (V2) until level
switch (L2) is triggered, then the sequence is repeated.
5
Q8 a) Draw the schematic diagram of an ac output module. How the high rating devices are

interfaced with the output module in a PLC.
5

b) Write a ladder program to implement the following process.

When the lights are turned off in a building, an exit door light is to remain on for an

additional 2 min time and the parking lot lights are to remain on for an additional 3 min

after the door light goes out.
5
Q9. (a) How the analog devices are interfaced with a PLC?
3

(b) What do mean by latching? Draw the ladder program for the start stop of a motor.
2

(c) Explain how the proportional, integral and derivative control is implemented with a

PLC.
5
NOTE : Disclosure of identity by writing mobile number or making passing request on any

page of Answer sheet will lead to UMC case against the Student.
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