Name of the College : SREE CHAITANYA COLLEGE OF ENGINEERING
University : JNTUH
Department : ELECTRICAL AND ELECTRONICS ENGINEERING
Subject Code/Name : 07A80204/PROGRAMMABLE LOGIC CONTROLLERS
Year/Sem : IV/II
Website : http://scce.ac.in/web/
Document Type : Model Question Paper
Download Model/Sample Question Paper : https://www.pdfquestion.in/uploads/scce.ac.in/4928-07A80204-PROGRAMMABLELOGICCONTROLLERS.pdf
SCCE Programmable Logic Controllers Question Paper
IV B.Tech II Semester Examinations,April/May 2012
Related : Sree Chaitanya College Of Engineering 07A80201 Utilization of Electrical Energy B.Tech Question Paper : www.pdfquestion.in/4929.html
Set No. 1
Electrical And Electronics Engineering
Time: 3 hours
Max Marks: 80
Answer any FIVE Questions :
All Questions carry equal marks :
1. (a) Explain flashing arrow pattern and registers.
(b) Explain PLC program for ashing arrow movement. [8+8]
2. (a) Explain general characteristics of registers.
(b) Explain module addressing.
(c) Explain I/O terminal addressing scheme.
(d) Explain holding registers. [16]
3. (a) Convert input signals to a form usable by input modules.
(b) Convert output module signals to usable valves for output devices. [8+8]
4. (a) Consider a flashing alarm as a subroutine and show its ladder logic circuit.
(b) Describe PLC move function in its block and in coil format. [8+8]
5. (a) Explain the function of microprocessor and memory function in a PLC system layout and connection.
(b) Explain the function of fixed memory in a operational section of a PLC.[10+6]
6. (a) Design gate logic relay logic and PLC logic for a motor control circuit with a process fan is to run only when all of the following conditions are met. Input 1 is o, input 2 is on or input 3 is on or both 2 & 3 are on, inputs 5 and 6 are both on, one or more of inputs 7, 8 or 9 are on
(b) Consider any PLC ladder diagram and show its equivalent gate diagram.[8+8]
7. Consider a start-stop-seal circuit. When the start button is depressed the coil energizes. When the button is released the coil remain on. It is held on by a sealing contact that is in parallel with the start button. The seal contact closes when the output coil goes on.
If the stop button is depressed, the coil goes o. For the above problem, show relay logic, its connection diagram, PLC logic and its connection diagram, PLC latch/unlatch logic. [16]
8. (a) Explain repeat cycling timer functions with example, where an output pulse becomes on and quickly o at a constant preset time interval.
(b) Explain one-shot operation of timer functions with example, where output b goes on for a specified time after output a is turned on. Output b will run for its specified time interval even if a is turned o during the b timing interval. [6+10]
Set No. 2
1. (a) Explain how holding registers are used in timers.
(b) Explain how holding registers are used in counters. [8+8]
2. (a) Explain analog BCD input and output systems.
(b) Explain analog input signal path and values.
(c) Explain analog add application.
(d) Explain BCD multi bit inputs and outputs system. [4+4+4+4]
3. (a) Explain how you apply FIFO function.
(b) Explain FIFO stacking program formats.
(c) Explain file arithmetic and logic (FAL) function briefly.
(d) Explain one shot (ONS), clear (CLR) and sweep function. [4+4+4+4]
4. (a) Draw the block diagram of the PLC system layout and connection and explain.
(b) Explain the advantages and disadvantages of PLC. [10+6]
5. Explain how to develop a drum/controller sequencer control system to operate a basic robot. [16]
6. (a) Write any eight Boolean expressions.
(b) For a given logic figure 1 show the conversions of given digital gate diagram into ladder diagram.
(c) For a given logic figure 2 show the conversions of given digital gate diagram into ladder diagram. [4+6+6]
7. A two-way hydraulic cylinder has two solenoids controlling it. Energizing one solenoid causes the cylinder to extend and energizing the other solenoid causes it to retract. A limit switch at each end indicates full retraction or full exten- sion.
Use two start-stop three wire controls, one for each direction. Construct atwo-directional control system, including inter locks, to control the solenoid. [16]
8. Explain interval time within a cycle timer functions with example, where we may require that an output come on 7.5 seconds after system startup, remain on for 4.5 seconds, and then go o and stay o. The interval would then be repeated only after the system is shut o and then turned back on. [16]