Instrumentation And Process Control Rr322301

Set No. 1

Code No: RR322301

III B.Tech II Semester Supplimentary Examinations, Aug/Sep 2007 INSTRUMENTATION AND PROCESS CONTROL (Bio-Technology) Time: 3 hours Max Marks: 80 Answer any FIVE Questions All Questions carry equal marks ⋆⋆⋆⋆⋆ 1. (a) Define time constant of a system. Write the expression for the time constant in terms of the process parameters of a liquid level system. (b) A tank operating at 3 metre head and 0.022 cubic metre/min outflow through a valve has a cross section area 0.9 square metre. Calculate the time constant. (c) If this system known to have time constant response requires 5 minutes to indicate 98% of the response, what can be the time constant? [4+6+6] 2. (a) Define self regulation ? (b) Explain how self and non self regulated systems operate for step input with examples. [5+11] 3. (a) Explain with analytic expression, the concept of a single controller mode which is anticipatory in nature. List its characteristics. (b) Why a pure derivative is not preferred? Draw the derivative controller output for the error given below figure3b. (Assume the relevant settings) [8+8]

Figure 3b 4. (a) Explain in detail with a neat sketch, the working principle of a pneumatic PID controller. Write a note on various time constants involved. (b) Outline the design steps involved in the implementation of an electronic PD controller and explain. [8+8] 5. (a) Describe the following types of disturbances with relevant sketches. i. Transient ii. Set point changes iii. Load changes. (b) Write a short note on the following errors. i. IAE. ii. ISE . 1 of 2

Set No. 1

Code No: RR322301 iii. ITAE.

[8+8]

6. (a) A quick - opening valve mover from closed to maximum open with 5 turns of a shaft. The shaft is driven through a 10:1 reducer from a stepping motor of 30 per step. If the maximum input pulse rate to the motor is 250 steps / sec, find the fastest time for the vale to move from closed to open. (b) Differentiate pneumatic - electric and hydraulic actuators.

[6+10]

7. (a) Give the schematic of single seated and double seated valves. (b) What are the advantages and disadvantages of single seated and double seated valves. [8+8] 8. (a) Explain clearly the split range control of the pressure in the steam header? (b) Determine the properties of the inner loop in a cascade control system and write the principle advantages of cascade control system? [8+8] ⋆⋆⋆⋆⋆

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Set No. 2

Code No: RR322301

III B.Tech II Semester Supplimentary Examinations, Aug/Sep 2007 INSTRUMENTATION AND PROCESS CONTROL (Bio-Technology) Time: 3 hours Max Marks: 80 Answer any FIVE Questions All Questions carry equal marks ⋆⋆⋆⋆⋆ 1. (a) A flow head equation has the equation q = hn . Calculate the resistance. (b) A liquid storage device is spherical in shape. Calculate the capacitance as a function of head. (c) If the outflow at a vessel is proportional to the square root of head, what shape vessel results in i. a steady change in head ii. a rate of change of head proportional to head?

[4+4+8]

2. (a) Say whether heated tank and an immersed thermometer with negligible interaction is interacting or non-interacting. Justify your answer. (b) Write the differential equations and determine the transfer functions individually for heated tank and thermometer. (c) Determine the overall transfer function of this combination. How is this transfer function related with the individual transfer function? [3+9+4] 3. (a) Explain with a neat sketch depicting the error vs controller output, the principle of a proportional controller action. (b) With an example, explain how offset error in proportional controller occurs. Suggest a way to overcome the offset error. [8+8] 4. (a) Explain in detail, the realization of proportional-integral action with the aid of bellows, flapper-nozzle etc. (b) Draw a three mode electronic controller and derive the expression for the output voltage. [8+8] 5. (a) Explain the following terms as applicable to system evaluation with necessary graphs. i. Stability ii. measure of quality . (b) Discuss the quarter - amplitude criterion to evaluate the response.

[8+8]

6. (a) What is the principle of a solenoid and explain how it can be used to change the gears of a two-position transmission. (Let an SCR is used to activate the solenoid coil). (b) A stepping motor has 130 steps per revolution. Find the digital input rate that producer 10.5 revolutions per second. [10+6] 1 of 2

Set No. 2

Code No: RR322301

7. (a) Give the schematic of single seated and double seated valves. (b) What are the advantages and disadvantages of single seated and double seated valves. [8+8] 8. (a) Explain the closed loop characterization of cascade control system. (b) Explain the primary and secondary loop gain adjustment in a cascade control system. [8+8] ⋆⋆⋆⋆⋆

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Set No. 3

Code No: RR322301

III B.Tech II Semester Supplimentary Examinations, Aug/Sep 2007 INSTRUMENTATION AND PROCESS CONTROL (Bio-Technology) Time: 3 hours Max Marks: 80 Answer any FIVE Questions All Questions carry equal marks ⋆⋆⋆⋆⋆ 1. (a) Write differential equation for the following single capacitance process as shown in the figure1a

Figure 1a (b) The above single capacitance level process has a normal operating head of 1.2 metre and a normal value of outflow of 3375 cubic centimetre per seconds. The cross section area of the vessel is 0.54 square metre. If the resistance to the flow is parabolic, determine the time constant of the system. (c) Show that the time constant of the above process is proportional to the time required to change the fluid in the vessel. [3+7+6] 2. Three identical tanks are operated in series in non-interacting fashion. For each tank, R=1 and t = 1. If the deviation in flow rate to the first tank is an impulse function of magnitude 2, determine (a) An expression for H(S) where H is the deviation in level in the third tank. (b) Obtain the expression for H(t). (c) Sketch the response H(t).

[7+6+3]

3. (a) Discuss the relative advantages and disadvantages of various composite control modes. (b) A three mode controller has Kp =2.5, Ki =2.5 sec−1 , Kd =2sec and PI (0) (controller output at t=0 ) =30%. Plot the controller output as function of time for the following error as shown in figure3b. [6+10]

Figure 3b 1 of 2

Set No. 3

Code No: RR322301

4. (a) With a neat circuit diagram, explain the realization of an electronic two position controller with adjustable neutral zone. (b) Design an electronic proportional controllers for (0-12v) error input, 10% proportional band and 50% zero error controller output. [8+8] 5. (a) What are the different tuning schemes of PID controllers? When do you propose single loop control schemes? (b) How are proportional and integral actions realized in a pneumatic controller? Obtain the transfer function of such a controller. How do you adjust the integrating time of a PI pneumatic controller? [6+10] 6. (a) Explain the baffle - Nozzle system with the help of its characteristic curves. (b) Explain the pneumatic booster and what is its need. (c) Differentiate between direct and reverse action final control operation.[6+6+4] 7. Write about the rotating shaft valves?

[16]

8. (a) Explain the design procedure of feed forward controller. (b) Discuss the principles of feed back- Augmented feed forward controller. [8+8] ⋆⋆⋆⋆⋆

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Set No. 4

Code No: RR322301

III B.Tech II Semester Supplimentary Examinations, Aug/Sep 2007 INSTRUMENTATION AND PROCESS CONTROL (Bio-Technology) Time: 3 hours Max Marks: 80 Answer any FIVE Questions All Questions carry equal marks ⋆⋆⋆⋆⋆ 1. (a) What are single capacity systems? Give one example and explain why it is called so? (b) Write the differential equation of this system and determine the transfer function. (c) Study the response of this pure capacity system to a step change in input. [5+5+6] 2. Three identical tanks are operated in series in non-interacting fashion. For each tank, R=1 and t = 1. If the deviation in flow rate to the first tank is an impulse function of magnitude 2, determine (a) An expression for H(S) where H is the deviation in level in the third tank. (b) Obtain the expression for H(t). (c) Sketch the response H(t).

[7+6+3]

3. (a) Explain the principle of different types of discontinuous controller modes with examples. Mention them applications. (b) Distinguish between multi position controller mode and floating control mode with neat sketches. [10+6] 4. (a) Explain in detail, the realization of proportional-integral action with the aid of bellows, flapper-nozzle etc. (b) Draw a three mode electronic controller and derive the expression for the output voltage. [8+8] 5. (a) Show by sketches how proportional and reset action rates are to be determined. What is the effect of the derivative action on maximum deviation and stabilizing time? (b) A PID controller has a steady out put pressure of 0.4 kg/cm2 . The set point is now lowered at the rate of 1cm/min. Obtain the nature of the output pressure. Assume KC =0.1 kg/cm2 /cm. TR =1.2 min. and TD = 0.5 min. [10+6] 6. (a) What is the principle of a solenoid and explain how it can be used to change the gears of a two-position transmission. (Let an SCR is used to activate the solenoid coil). (b) A stepping motor has 130 steps per revolution. Find the digital input rate that producer 10.5 revolutions per second. [10+6] 1 of 2

Set No. 4

Code No: RR322301

7. (a) Give the schematic of single seated and double seated valves. (b) What are the advantages and disadvantages of single seated and double seated valves. [8+8] 8. What type of controllers would you use for two controllers of a cascade system? How would you tune them? Discuss the methodology to select the adjusted parameters of the two controllers? [16] ⋆⋆⋆⋆⋆

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