Rr220305-instrumentation-and-control-systems

Set No. 1

Code No: RR220305

II B.Tech II Semester Supplimentary Examinations, Aug/Sep 2008 INSTRUMENTATION AND CONTROL SYSTEMS ( Common to Mechanical Engineering, Production Engineering and Automobile Engineering) Time: 3 hours Max Marks: 80 Answer any FIVE Questions All Questions carry equal marks ⋆⋆⋆⋆⋆ 1. (a) Discuss briefly on the reliability of measurement systems. Explain how reliability improvement can be achieved. (b) “A pricise instrument need not be accurate” explain.

[8+8]

2. What are mechanical Tachometers? Explain with examples. Describe the disadvantages of mechanical Tachometers. [16] 3. With neat diagrams explain the construction, working principle of different types of pressure thermometers, compare them. [16] 4. (a) Define i. Static pressure ii. Dynamic pressure Explain the difficulties that are encountered in measurement of dynamic pressures. (b) Describe the construction and theory of well type of manometers. (c) Describe the construction and working of a Bourdon tube.

[16]

5. (a) List out the advantages and limitations of direct method of level measurement. (b) Describe with neat sketch the functioning of any two types of displacer type liquid level measuring instruments. [16] 6. (a) How seismic instruments are used for measuring acceleration. Explain in detail. (b) What is the importance of humidity control in process industries?

[8+8]

7. (a) Classify strain gauges. (b) Describe the method of surface preparation and bonding techniques while fixing strain gauge on a metallic member. [4+12] 8. A common example of a two-input control system is a home shower with separate valves for hot and cold water. The objective is to obtain (a) a desired temperature of the shower water and (b) a desired flow of water

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Set No. 1

Code No: RR220305

Sketch a block diagram of the closed loop control system. Discuss the salient feature of this multivariable control system. [16] ⋆⋆⋆⋆⋆

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Set No. 2

Code No: RR220305

II B.Tech II Semester Supplimentary Examinations, Aug/Sep 2008 INSTRUMENTATION AND CONTROL SYSTEMS ( Common to Mechanical Engineering, Production Engineering and Automobile Engineering) Time: 3 hours Max Marks: 80 Answer any FIVE Questions All Questions carry equal marks ⋆⋆⋆⋆⋆ 1. (a) What do you mean by instrumentation? Write the objectives of instrumentation. (b) State and explain the desirable static and dynamic characteristics of an instrument. [16] 2. (a) Explain operation of ionization transducer with a neat sketch and write the applications. (b) Describe the construction and principle of i. LVDT ii. Variable reluctance displacement transducer.

[16]

3. Explain the transducers used for following temperature measurements. (a) Temperature of an oven having range of 0 to 1000o C (b) Temperature of molten steel of −50o C (c) Liquid at a temperature of −50o C (d) Furnace having temperature range 0 to 1700o C

[4+4+4+4]

4. (a) With the aid of neat sketch, explain the working principle of dead - weight type tester. (b) Discuss various types of elastic pressure sensing elements used in electrical transducers. [16] 5. With neat sketches explain in detail the functioning of any two flow measuring instruments working on Faraday’s law of induced voltage. [16] 6. (a) How relative humidity is measured using hygrometer? (b) A seismic type accelerometer is relatively rugged compared to a seismic type vibrometer. Comment. [16] 7. (a) What is the need for rosette? (b) How dew point temperature is measurement. (c) Describe the tension measurement using strain gauge with neat diagram. [4+4+8]

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Set No. 2

Code No: RR220305

8. (a) Distinguish between open and closed loop systems. Explain with suitable examples. (b) How water level in a boiler is controlled? ⋆⋆⋆⋆⋆

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[12+4]

Set No. 3

Code No: RR220305

II B.Tech II Semester Supplimentary Examinations, Aug/Sep 2008 INSTRUMENTATION AND CONTROL SYSTEMS ( Common to Mechanical Engineering, Production Engineering and Automobile Engineering) Time: 3 hours Max Marks: 80 Answer any FIVE Questions All Questions carry equal marks ⋆⋆⋆⋆⋆ 1. (a) Discuss briefly on the reliability of measurement systems. Explain how reliability improvement can be achieved. (b) “A pricise instrument need not be accurate” explain.

[8+8]

2. (a) Give detailed classification of speed measuring devices with examples. (b) Write short note on Induction Sensors for speed measurement.

[8+8]

3. (a) A thermistor has a negative resistance temperature co-efficient of 5% over a temperature range of 250 C. What is the resistance at 350 ? (b) Discuss in detail about thermopile.

[8+8]

4. (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.

[8+4+4]

5. (a) Explain with a neat sketch, the principle of operation of various solid level indicators. (b) 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. [16] 6. (a) How relative humidity is measured using hygrometer? (b) A seismic type accelerometer is relatively rugged compared to a seismic type vibrometer. Comment. [16] 7. (a) Discuss the salient features and applications of electrical strain gauges. (b) Describe the properties of materials used for strain gauges. (c) List the various factors that are considered for the selection of metallic strain gauges. [4+4+8] 8. (a) Distinguish between open-loop and closed loop control systems with the help of a suitable diagram. (b) Illustrate your answer using block diagram schematics. (c) Identify the system parameters and components in each case. ⋆⋆⋆⋆⋆

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[16]

Set No. 4

Code No: RR220305

II B.Tech II Semester Supplimentary Examinations, Aug/Sep 2008 INSTRUMENTATION AND CONTROL SYSTEMS ( Common to Mechanical Engineering, Production Engineering and Automobile Engineering) Time: 3 hours Max Marks: 80 Answer any FIVE Questions All Questions carry equal marks ⋆⋆⋆⋆⋆ 1. (a) Define the following: i. ii. iii. iv.

Measurand Primary measuring element Measurement Calibration

(b) What do you mean by functional elements? Explain the division of a measurement system into fractional elements with examples. [8+8] 2. (a) Give the classification of inductive transducers indicating their principle. (b) Describe in detail the construction and working of an inductive and a capacitive transducers to measure linear displacement. [6+10] 3. (a) What are the different types of materials commonly used in thermisters? (b) Give the various forms of thermisters. (c) Explain the temperature-resistance relation of NTC thermister.

[4+4+8]

4. (a) Describe the construction and working or c-type, spiral type and helical type Bourdon gauges with neat diagrams. (b) Describe the construction, working and theory of a diaphragm type strain gauge transducer using four strain gauges. Describe how they are connected in a wheetstone bridge and what is the output obtained. List their advantages and disadvantages. [16] 5. (a) Explain with a neat sketch, the principle of operation of various solid level indicators. (b) 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. [16] 6. (a) Compare the working of a servo and digital accelerometers. (b) Name the different types of hygrometers used for measuring humidity. 7. (a) Discuss the salient features and applications of electrical strain gauges. (b) Describe the properties of materials used for strain gauges.

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[16]

Set No. 4

Code No: RR220305

(c) List the various factors that are considered for the selection of metallic strain gauges. [4+4+8] 8. (a) What are the basic elements of a control system? Explain. (b) Describe a control system to fill a tank with water after it is emptied through an output at the bottom. This system automatically stops the inflow of water when the tank is filled. Draw the block diagram of the system. [6+10] ⋆⋆⋆⋆⋆

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