PROCESS DYNAMICS AND CONTROLS
1. Define the Laplace transform
2. What is initial value theorem?
3. Define step function and impulse function
4. Give the transfer function for second order system
5. Define the terms: Decay ratio and Rise time
6. Define transportation lag
7. Differentiate between negative feedback and positive feedback
8. What is meant by on-off control?
9. Express the proportional controller
10. What is dead time?
11. Define the stability of a linear system
12. What is meant by controller timing?
13. Define amplitude ration
14. Name any two flow metering of liquids
15. Explain the terms open loop and closed loop systems
16. What is the advantage of using resistance thermometers?
17. What are radiation pyrometers? Where is it used?
18. What are the objectives of automatic process control?
19. Define Nyquist stability criteria
20. Explain the cross over frequency.
21. Gain margin and phase margin
22. Control valves
23. Interacting systems
24. Nyquist stability criterion
25. Instrument lag
26. Proportional band
27. Closed and open loop systems
28. Response of second order systems to step change
29. Linearization
30. Routh test
31. Pneumatic relay
32. Dead time
33. Final control elements
34. Frequency response technique
35. Hydraulic control systems
36. Pressure transducers
37. Transportation lag
38. Nichols chart
39. Optimum controller settings
40. Ratio control
41. Feed forward control
42. Essential elements of pneumatic controller
43. Stability analysis
44. On-off controllers
45. Decay ratio
46. Inverse derivative control
47. Integral action.
48. Sketch the transient response characteristics of 1) a bare thermocouple 2) a shielded thermocouple.
49. Draw electrical analogies for these two devices.
50. Discuss the manometer dynamics with respect to the damping coefficient. On what physical parameters of the manometer does this coefficient depend?
51. Draw the block diagram of a control system illustrating a cascade control loop. Explain its purpose.
52. Discuss on the criteria for specifying the control and controller settings.
53. Draw the instrumentation flow diagram for a shell and tube heat exchanger. State the importance of such diagrams.
54. With a neat sketch, explain the working of a proportional plus derivative mode of control. Why the derivative controller cannot be used independently.
55. Show by plot the transient output response of a derivative controller when it has been disturbed by 1) Linear input 2) Sinusoidal input 3)Step input
56. Write short notes on the dynamic behavior and dynamic characteristics of an instrument.
57. Explain the terms 'amplitude ratio', 'proportional band', 'transducer', 'distance velocity lag' and 'offset'.
58. Describe how proportional plus integral action can be generated in a pneumatic controller. State under what circumstances it is an advantage to use this combination. Under what conditions would you prefer to replace the integral by derivative action?
59. State and explain Ziegler-Nichols rules for controller settings.
60. Name and define all the basic elements of a control system and show in a block diagram their positions in the closed-loop which forms the system. Indicate where and how time lags can arise in the system and explain how they add to the difficulty of control.
61. Give one example each of a system with zero order and first order dynamics. Derive the transfer function of a first order system.
62. Discuss the merits and demerits in using hydraulic, pneumatic and electric control system in process control.
63. Explain, what is meant by the terms a) capacity lag b) transfer lag c) transportation lag d) dead time
64. Explain with the help of a control circuit, how temperature of water in a shell and tube heat exchanger, heated by hot oil (shell side) can be controlled.
65. Explain how an on-off controller having no differential gap, is used to control liquid level in a tank and indicate the draw backs.
66. Discuss the factors that are to be considered in choosing a feed back or feed forward controller in process control.
67. Explain with the help of a neat sketch, the working of a pneumatic proportional plus integral (PI) controller to control temperature in a process.
68. Write the expression for proportional (P), proportional plus integral (PI), proportional plus derivative (PD) and proportional plus integral plus derivative (PID) control actions and explain the terms used therein.
69. Derive an expression for the step response in inlet flow rate to two non-inter acting tanks in series with equal time constant.
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