Download GTU (Gujarat Technological University) BE/BTech (Bachelor of Engineering / Bachelor of Technology) 2019 Winter 8th Sem New 2182001 Programmable Logic Controllers Previous Question Paper
Seat No.: ________ Enrolment No.___________
GUJARAT TECHNOLOGICAL UNIVERSITY
BE - SEMESTER ? VIII (New) EXAMINATION ? WINTER 2019
Subject Code: 2182001 Date: 27/11/2019
Subject Name: Programmable Logic Controllers
Time: 02:30 PM TO 05:00 PM Total Marks: 70
Instructions:
1. Attempt all questions.
2. Make suitable assumptions wherever necessary.
3. Figures to the right indicate full marks.
MARKS
Q.1 (a) Explain scan cycle of PLC. 03
(b) Why isolation is needed between plant and PLC CPU? Also explain
how this isolation is provided?
04
(c) Using suitable diagram, explain single channel DC input card for
PLC.
07
Q.2 (a) Design and draw PLC ladder diagram for the following Boolean
Expression.
X=AB(C+D)(E+F)
Where, X= digital output and A,B,C,D,E and F are digital inputs.
03
(b) Give FBD programs for the following
(i) Two input NOR gate
(ii) Two input NAND gate
04
(c) Write PLC Instruction List (IL) program to control following system
operation:
When momentary START (NO) pushbutton is pressed, and output X
will turn on. If another pushbutton A (NO) is pressed momentary,
another output Y will turn only if X is in ON condition. If X in not in
ON condition, output Z will turn when A is pressed. Furthermore, if
pushbutton C (NC) is pressed momentary, output P will turn ON if Y
is on and output F will turn ON if Z is on.
All the outputs will turn OFF if STOP (NC) pushbutton is pressed
momentary and a LED will turn ON when the STOP is pressed. The
LED will turn OFF when the START is pressed again.
07
OR
(c) Write a detailed note on SFC programming of PLC with suitable
programming example.
07
Q.3 (a) What is MCR in PLC programming? Explain need of MCR. 03
(b) Explain latching relay used in PLC FBD programming. 04
(c) Using timing diagram and programming example, explain Retentive
ON Delay timer used in PLC ladder diagrams.
07
OR
Q.3 (a) Why latching is needed in ladder diagrams? How it is done? 03
(b) Explain OFF delay timer instructions in PLC using timing diagram. 04
(c) Explain various counter functions used in PLC ladder diagrams. 07
Q.4 (a) Design and draw PLC FBD for the following requirement:
When input I1 is available momentarily, outputs Q1, Q2 and Q3 will
turn ON and will remain in ON condition even if I1 go off. If input
I2 is available, outputs Q1 and Q2 will turn OFF. If input I3 is
available, outputs Q3 will turn OFF.
03
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1
Seat No.: ________ Enrolment No.___________
GUJARAT TECHNOLOGICAL UNIVERSITY
BE - SEMESTER ? VIII (New) EXAMINATION ? WINTER 2019
Subject Code: 2182001 Date: 27/11/2019
Subject Name: Programmable Logic Controllers
Time: 02:30 PM TO 05:00 PM Total Marks: 70
Instructions:
1. Attempt all questions.
2. Make suitable assumptions wherever necessary.
3. Figures to the right indicate full marks.
MARKS
Q.1 (a) Explain scan cycle of PLC. 03
(b) Why isolation is needed between plant and PLC CPU? Also explain
how this isolation is provided?
04
(c) Using suitable diagram, explain single channel DC input card for
PLC.
07
Q.2 (a) Design and draw PLC ladder diagram for the following Boolean
Expression.
X=AB(C+D)(E+F)
Where, X= digital output and A,B,C,D,E and F are digital inputs.
03
(b) Give FBD programs for the following
(i) Two input NOR gate
(ii) Two input NAND gate
04
(c) Write PLC Instruction List (IL) program to control following system
operation:
When momentary START (NO) pushbutton is pressed, and output X
will turn on. If another pushbutton A (NO) is pressed momentary,
another output Y will turn only if X is in ON condition. If X in not in
ON condition, output Z will turn when A is pressed. Furthermore, if
pushbutton C (NC) is pressed momentary, output P will turn ON if Y
is on and output F will turn ON if Z is on.
All the outputs will turn OFF if STOP (NC) pushbutton is pressed
momentary and a LED will turn ON when the STOP is pressed. The
LED will turn OFF when the START is pressed again.
07
OR
(c) Write a detailed note on SFC programming of PLC with suitable
programming example.
07
Q.3 (a) What is MCR in PLC programming? Explain need of MCR. 03
(b) Explain latching relay used in PLC FBD programming. 04
(c) Using timing diagram and programming example, explain Retentive
ON Delay timer used in PLC ladder diagrams.
07
OR
Q.3 (a) Why latching is needed in ladder diagrams? How it is done? 03
(b) Explain OFF delay timer instructions in PLC using timing diagram. 04
(c) Explain various counter functions used in PLC ladder diagrams. 07
Q.4 (a) Design and draw PLC FBD for the following requirement:
When input I1 is available momentarily, outputs Q1, Q2 and Q3 will
turn ON and will remain in ON condition even if I1 go off. If input
I2 is available, outputs Q1 and Q2 will turn OFF. If input I3 is
available, outputs Q3 will turn OFF.
03
2
(b) Develop and draw ladder diagram for the following system:
An output X will turn ON when 10 parts are sensed at position A or
when 20 parts are sensed at position B. Add system START and
STOP inputs of your choice and clearly mention them.
04
(c) Using suitable diagram, explain analog output module in PLC. 07
OR
Q.4 (a) Design and draw PLC ladder program for systems that will carry out
the following tasks:
Switch on an output A 10 seconds after pressing a pushbutton (NO)
momentary and keep the output on for the duration of 20 seconds.
If a stop (NC) input is given at any time, switch off the outputs if on
03
(b) Design and draw PLC ladder diagram for the following:
A flash light will start operating (ON time is 10 seconds and OFF
time is 20 seconds) when a pushbutton A (NO) is pressed
momentarily. The flash light will continue operating until a
pushbutton B (NC) is pressed momentarily.
04
(c) Write a detailed note on arithmetic functions in PLC. 07
Q.5 (a) Explain unconditional JUMP operation in PLC programming. 03
(b) Design and draw PLC ladder diagram for the following equation.
X=(A+B)(C+D)
Where, X is analog output and A,B,C,D are analog inputs.
04
(c) Explain various data comparison functions in PLC. 07
OR
Q.5 (a) Develop PLC ladder diagram to multiply two numbers stored in some
PLC registers. Store the result in one of the PLC registers.
03
(b) Using suitable diagrams, explain Jump within Jump operation in PLC
ladder diagram.
04
(c) Write a detailed note about commissioning of PLCs. 07
*************
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This post was last modified on 20 February 2020