Discussion
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- Question
The transfer function of a pure dead time system with dead time ?d is
Options- A. 1/(?ds + 1)
- B. ?ds + 1
- C. e-?ss
- D. e?ds
- Correct Answer
- e-?ss
- 1. Process degree of freedom indicates __________ number of controllers to be used.
Options- A. the maximum
- B. the minimum
- C. both maximum and the minimum
- D. nothing about the Discuss
- 2. Liquid levels in autocalves are measued by
Options- A. simple float
- B. differential float type manometer
- C. glass gauge
- D. none of these Discuss
- 3. Dead zone in an instrument must be less than __________ percent of the scale.
Options- A. 0.2
- B. 1.5
- C. 4
- D. 8 Discuss
- 4. Bode stability method uses __________ loop transfer function.
Options- A. open
- B. closed
- C. either (a) or (b)
- D. neither (a) nor (b) Discuss
- 5. Flow rate through an orifice is __________ the pressure differential.
Options- A. proportional to
- B. inversely proportional to the square root of
- C. proportional to the square root of
- D. inversely proportional to the square of Discuss
- 6. Gas analysis is commonly done using the
Options- A. thermal conductivity cell
- B. X-ray diffraction
- C. mass spectrometer
- D. emission spectrometer Discuss
- 7. A bimetallic thermometer as compared to industrial mercury in glass thermometer has almost the same
Options- A. temperature measuring range (- 40°C to 450°C).
- B. accuracy (± 1% of span).
- C. speed of response.
- D. all a, b & c. Discuss
- 8. Suppose that the gain, time constant and dead time of a process with the following transfer function:Gc(s) = 10 exp( - 0.1s)/(0.5s + 1) are known with a possible error of ± 20% of their values. The largest permissible gain Kc of a proportional controller needs to be calculated below taking the values of process gain, time constant and dead time as
Options- A. 8, 0.6, 0.08
- B. 12, 0.6, 0.12
- C. 8, 0.6, 0.12
- D. 12, 0.4, 0.08 Discuss
- 9. For a feed back control system to be stable, the
Options- A. roots of the characteristic equation should be real.
- B. poles of the closed loop transfer function should lie in the left half of the complex plane.
- C. Bode plots of the corresponding open loop transfer function should monotoni-cally decrease.
- D. poles of the closed loop transfer function should lie in the right half of the complex plane. Discuss
- 10. __________ controller has the maximum stabilising time.
Options- A. P
- B. PD
- C. PI
- D. PID Discuss
Process Control and Instrumentation problems
Search Results
Correct Answer: the maximum
Correct Answer: differential float type manometer
Correct Answer: 0.2
Correct Answer: open
Correct Answer: proportional to the square root of
Correct Answer: thermal conductivity cell
Correct Answer: all a, b & c.
Correct Answer: 12, 0.6, 0.12
Correct Answer: poles of the closed loop transfer function should lie in the left half of the complex plane.
Correct Answer: PI
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