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)
Subject Code : EI-310/DE-1.5
M.Code : 58040
Time : 3 Hrs. Max. Marks : 60
SECTION-A is COMPULSORY consisting of TEN questions carrying T WO marks
SECTION-B contains FIVE questions carrying FIVE marks each and students
have to attempt any FOUR questions.
SECTION-C contains T HREE questions carrying T EN marks each and students
have to attempt any T WO questions.

Q1 Answer briefly :

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?

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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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.

Q7 a) Explain the memory organization of a PLC. Name the different types of data files.

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.
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.

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.
Q9. (a) How the analog devices are interfaced with a PLC?

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

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

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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This post was last modified on 04 November 2019