Reg

no:

St.MOTHER THERESA ENGINEERING COLLEGEB.E.,/ B.Tech., DEGREE EXAMINATION, COMMON INTERNAL ASSESSMENT TEST – II

Seventh SemesterMechanical EngineeringME2401 – Mechatronics

(Regulation 2008)

Time: 3 Hours Maximum marks: 100 marks

Answer ALL questions

PART - A (10x2=20 marks)

1. What is PLC? 2. Mention the two specific features of PLCs.3. What is an internal relay in PLC? 4. What is latching in PLCs?5. State the function of counter6. Define ladder logic. 7. What are the logic functions that can be obtained by using switches in series?8. What is shift register? How many data is required for a shift-register? 9. What is the role of opto – isolator in robot control? 10. Identify the main sensors used in domestic washing machine.

PART – B (5x16=80 marks)11. a. Draw a detailed block diagram and explain the architecture of PLC. (16)

OR b. i) Explain the configuration or specification of a PLC. (8) ii) Draw the ladder diagram and PLC program for the following logic gates: (8) (a) AND (b) OR (c) NAND (d) NOR (e) XOR (f) NOT12. a. i) Explain the functioning of delay on, cascaded timers, on-off cyclic timers and delay-off timers with ladder diagrams.(8) ii) Enumerate the difference between a PLC and a personal computer. (4) iii) Explain latching with ladder diagram. (4)

OR b. i) Explain data handling in PLC. (8) ii) Explain how the shift register can be used for sequencing events? (8)13. a. i) Devise a circuit that could be used with a domestic washing machine to switch on pump to pump water for 100 sec into the machine then switch off and switch on a heater for 50 sec to heat the water. The heater is then switched off and another pump is to empty the water from the machine for 100 sec. (8) ii) Devise a circuit that can be used to start a motor and then after a delay of 100 sec start a pump. When the motor is switched off there should be a delay of 10 sec before the pump is switched off. (8)

OR

13. b. i) Create a ladder diagram for the following application: A pneumatic system with double-solenoid valves controls two double acting cylinders A and B. The sequence of cylinder operations are as follows: Cylinder A extends followed by cylinder B extending, then the cylinder B retracts and finally the cycle is completed by the cylinder A retracting. Explain the logic of the PLC circuit used. (8) ii) Devise a circuit that could be used with a conveyor belt which is used to move an item to a work station. The presence of the item at the work station is detected by means of breaking a contact activated by a beam of light to a photo sensor. There it stops for 100s for an operation to be carried out before moving on and off the conveyor. The motor for the belt is started by a normally open start switch and stopped by a normally closed switch.(8) 14. a. i) A work piece is loaded on a conveyor belt and operates between two limits of travel A and B. When limit switch at station A is activated, the conveyor moves forward. When limit switch at station B is activated, the conveyor changes direction. Pressing the start button causes the motor to run in the forward direction and pressing the stop button stops the motor. Create a ladder logic diagram and explain. (8) ii) Sketch a ladder diagram and explain for pressure alarm. Alarm should be sounded if a sensor indicates the pressure above 2 bar and remain sounding until the pressure falls below 1 bar.

OR b. Explain about the design of a mechatronics system considering wind screen wiper motion as an example. (16) 15. a. i) Explain the various design process involving different stages. (8) ii) What are the difference between traditional and mechatronics designs? (8)

OR b. Explain with a diagram how a microcontroller can be used to control solenoid valves to actuate a robot unit. (16)

Prepared by Verified by HOD/MECHMr. Karthisan (Name & Signature)Mrs. Mc luret