R05321402-instrumentation-and-control-system

Set No. 1

Code No: R05321402

III B.Tech Supplimentary Examinations, Aug/Sep 2008 INSTRUMENTATION AND CONTROL SYSTEM (Mechatronics) Time: 3 hours Max Marks: 80 Answer any FIVE Questions All Questions carry equal marks ⋆⋆⋆⋆⋆ 1. Explain the dynamic response characteristics of first order instruments to step, ramp and sinusoidal inputs. [16] 2. (a) How resistance is measured in RTD thermometer? Will the lead wires resistance has any effect on the measurement? If so how is it compensated? (b) What are the disadvantages of solid expansion thermometers? By means of neat sketches explain the working of a solid expansion thermometer. [8+8] 3. (a) With the aid of neat sketch, explain the working principle of dead ?weight type Tester. (b) Derive an equation for the differential pressure based on the movement of the liquid in the inclined column only. [8+8] 4. Explain the construction, working and applications of the following types of flow Meters: (a) Magnetic flow meter (b) Turbine flow meter.

[8+8]

5. (a) A seismic type accelerometer is relatively rugged compared to a seismic type vibrometer. Comment (b) What is the working principle of a stroboscope? (c) What are the different methods of converting vibration into a voltage? Explain any one in detail. [4+4+8] 6. (a) What is a bonded strain gauge? (b) List the main advantages and limitations of semiconductor strain gauges. (c) Explain one method of temperature compensation using an adjacent arm compensating gauge. [2+6+8] 7. (a) What are the various devices to measure force? Explain the constructional details of multi lever type. (b) With neat sketch explain the working principle of Strain gauge load cell. [10+6] 8. (a) Sketch and explain position control using servo motor. (b) Sketch and explain open loop and closed loop temperature control system with block diagrams. 1 of 2

Set No. 1

Code No: R05321402

(c) Briefly explain about positive feedback and negative feed back. ⋆⋆⋆⋆⋆

2 of 2

[6+6+4]

Set No. 2

Code No: R05321402

III B.Tech Supplimentary Examinations, Aug/Sep 2008 INSTRUMENTATION AND CONTROL SYSTEM (Mechatronics) Time: 3 hours Max Marks: 80 Answer any FIVE Questions All Questions carry equal marks ⋆⋆⋆⋆⋆ 1. (a) Classify measuring instruments. (b) What are desired, modifying and interfering inputs for a measurement system? Give examples for each of these quantities. What is the influence of these on the final output? [6+10] 2. (a) Differentiate between rare metal thermocouples and base metal thermocouples. (b) Design a measurement system for displacement measurement using LDR (Light dependent resistor) as sensor. [6+10] 3. (a) What is a differential pressure cell? (b) Elucidate the basic principle of operation of McLeod vacuum gauge with necessary diagram. (c) List the limitations of a McLeod vacuum gauge used to measure pressure. [2+10+4] 4. Explain with a neat sketch, the principle of operation of a bubbler and Float level indicator. [16] 5. Describe the basic concept of the seismic instrument. Under what conditions is a seismic instrument suitable for (a) amplitude measurement and (b) Acceleration measurements.

[16]

6. (a) Explian the method of measuring force using strain gauge. (b) Why bridge circuit is necessary for a strain gauge? Explain how the bridge circuit is used with a strain gauge. [8+8] 7. (a) Define the various terms related to humidity. (b) What are the hygroscopic materials? Explain the working of any one of the absorption hygrometers. [8+8] 8. (a) Briefly explain the different types of control systems. (b) Describe the working of one automatic control system used in practice. Outline functional elements of that system. [6+10] ⋆⋆⋆⋆⋆ 1 of 1

Set No. 3

Code No: R05321402

III B.Tech Supplimentary Examinations, Aug/Sep 2008 INSTRUMENTATION AND CONTROL SYSTEM (Mechatronics) Time: 3 hours Max Marks: 80 Answer any FIVE Questions All Questions carry equal marks ⋆⋆⋆⋆⋆ 1. (a) Distinguish between direct and indirect methods of measurement with suitable examples. (b) What are desired, modifying and interfering inputs for an instrumentation system? How do you correct the effects of modifying and interfering inputs by the method of signal filtering? Explain by means of suitable examples.[6+10] 2. (a) Differentiate between rare metal thermocouples and base metal thermocouples. (b) Design a measurement system for displacement measurement using LDR (Light dependent resistor) as sensor. [6+10] 3. (a) Describe the construction, working and theory of a Bridgman gauge for measurement of high pressures. (b) Briefly explain the principle employed in manometers used for the measurement of pressure. [10+6] 4. (a) Explain the working principle of Capacitance liquid level sensor. (b) Describe the working of a cryogenic fuel level indicator. What are its advantages and limitations? [6+10] 5. Describe the following: (a) Working principle of Centrifugal speed tachometer (b) Working principle of Vibration reed tachometer (c) Revolution counter.

[6+6+4]

6. (a) Explain the principle of operation of electrical resistance strain gauges and their merits and demerits. (b) Compare the Wheatstone bridge circuit and ballast circuit for strain measurement. [8+8] 7. (a) Explain how Spring balances can be used for measurement of force. Describe their working ,advantages and limitations. (b) Define the Psychometric terms: i. Relative humidity ii. Dew point temperature 1 of 2

Set No. 3

Code No: R05321402 iii. Wet bulb temperature.

[10+6]

8. (a) How feed back can be used to reduce the effect of various spurious inputs in an instrumentation system? Draw a block diagram representation of a generalized feed back control system .Identify the various system components and state clearly the function performed by each component. (b) Distinguish between: i. Velocity control ii. Acceleration control

[10+6] ⋆⋆⋆⋆⋆

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Set No. 4

Code No: R05321402

III B.Tech Supplimentary Examinations, Aug/Sep 2008 INSTRUMENTATION AND CONTROL SYSTEM (Mechatronics) Time: 3 hours Max Marks: 80 Answer any FIVE Questions All Questions carry equal marks ⋆⋆⋆⋆⋆ 1. (a) Differentiate between static and dynamic characteristics. (b) A mercury thermometer which was initially at 200 C was immersed in a boiling water bath at 1000 C. The following temperatures were observed in the thermometer over a period of time. Time(sec) 0.0 1.2 3.0 5.6 8.0 11.0 15.0 18.0 Meter reading(0 c) 20 40 60 80 90 95 98 99 Draw the response on a graph sheet and find the time constant. [6+10] 2. (a) Explain the working of vapour pressure thermometer by means of neat sketches. (b) Explain the laws of thermocouple.

[8+8]

3. (a) Illustrate the bellows arrangement used to measure differential pressure. (b) List the gauges for the measurement of high and medium pressures. (c) Explain any one high pressure measuring device.

[6+2+8]

4. (a) Explain how “a wire mounted normal to probe axis”, type hot wire anemometer is used in flow measurement. Enumerate the principle of operation and its limitations. (b) List out the important of calibration of flow measuring instruments.

[12+4]

5. Describe the functioning of a stroboscope and describe and explain how speed of a rotating shaft can be measured using a single pattern and multi pattern disc. [16] 6. (a) If a strain gauge has a low gauge factor, what does it indicate. (b) Name the various types of strain gauges for different applications. (c) Distinguish between bonded and unbonded type of resistance strain gauge. [3+3+10] 7. (a) Explain how a sling psychrormeter is used to determine the dry and the wet bulb Temperatures. (b) Explain the method of measuring force using strain gauges.

[10+6]

8. (a) Suggest a simple control system which automatically turns on a room lamp at dusk and turn it off in day light . Draw the schematics and block diagram of the suggested control system. (b) Distinguish between: i. Position control 1 of 2

Set No. 4

Code No: R05321402 ii. Acceleration control.

[8+8] ⋆⋆⋆⋆⋆

2 of 2