Download PTU B.Tech 2020 March EE 7th and 8th Sem Microcontroller And Plc Question Paper

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Roll No. Total No. of Pages : 02

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INSTRUCTIONS TO CANDIDATES :

1. SECTION-A is COMPULSORY consisting of TEN questions carrying TWO marks each.
2. SECTION-B contains FIVE questions carrying FIVE marks each and students have to attempt any FOUR questions.
3. SECTION-C contains THREE questions carrying TEN marks each and students have to attempt any TWO questions.

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SECTION-A

Q1 Answer briefly :

1. Differentiate between a microcontroller and a microprocessor.
2. What is an embedded system?
3. What is criterion for choosing a microcontroller for a particular application?

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4. If bank 1 registers are being used, the default value of the stack pointer cannot be used. Why?
5. What is the difference between a machine cycle and a clock cycle?
6. Differentiate between the packed and unpacked BCD numbers.
7. What is checksum byte?
8. Define a programmable logic controller.

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9. Lists are the factors affecting the memory size needed for a particular PLC.
10. List all the programming languages of a PLC.

SECTION-B

Q2 Contrast and compare the different addressing modes of 8051 microcontroller with suitable examples.

Q3 Create a square wave with an ON time 2ms and an OFF time of 10ms on all pins of port 0. Assume an XTAL of 22MHz.

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Q4 List and explain the registers of 8051 having the bit-addressability. What are the advantages of bit-addressability?

Q5 Outline and explain the sequence of events involved in a single PLC program scan. “The scan time puts a limit on the speed of events”. Comment.

Q6 Draw the schematic diagram of a discrete input and output module and explain each section.

SECTION-C

Q.7 Devise ladder programs for systems that will carry out the following tasks :

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1. Switch on a pump when the water level in a tank rises to above 1.2 m and switch it off when it falls below 1.0 m.
2. Switch on a pump; then 100 s later, switch on a heater; then a further 30 s later, switch on the circulating motor.
3. Switch on a heater when the temperature is less than the set temperature.
4. Turn on a lamp when a data source is not giving 100.

Q8 a) Explain the architecture of the PLC in detail: Define the function of each section.

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b) How the analog devices are interfaced?

Q9 a) What are the advantages of using programmable logic over discrete logic? How does a structured ASIC differ from the traditional ASIC and the PLD?

b) Two switches are connected to the pins P0.1 and P0.2. These are also vectored to interrupt locations 0003H Write a program to test which key is pressed, or to verify if both the keys are pressed.

Write a program to implement an on-off temperature control. Assume a temperature sensor is connected to an input port to read the temperature and a heater to the output port through a relay to control the temperature.

Explain the features of the 8255 chip and its mode selection.

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NOTE : Disclosure of Identity by writing Mobile No. or Making of passing request on any page of Answer Sheet will lead to UMC against the Student.

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