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- Question
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.
- Correct Answer
- poles of the closed loop transfer function should lie in the left half of the complex plane.
- 1. 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
- 2. 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
- 3. Gas analysis is commonly done using the
Options- A. thermal conductivity cell
- B. X-ray diffraction
- C. mass spectrometer
- D. emission spectrometer Discuss
- 4. 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 Discuss
- 5. 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
- 6. __________ controller has the maximum stabilising time.
Options- A. P
- B. PD
- C. PI
- D. PID Discuss
- 7. __________ type of element is normally not used in the bimetallic thermometers.
Options- A. Flat spiral
- B. Bourdon tube
- C. Single helix
- D. Multiple helix Discuss
- 8. Flow rate of sludge is not measured by a/an
Options- A. orificemeter
- B. open weir
- C. kennison nozzle
- D. both(b)&(c) Discuss
- 9. Which of the following is not a second order instrument?
Options- A. Mercury in glass thermometer with covering.
- B. Bare mercury in glass thermometer.
- C. Pressure gauge with one bellow, two tubes and a tank.
- D. None of these. Discuss
- 10. Thermal wells used in temperature measurements should have
Options- A. very thick walls.
- B. low emissivity.
- C. polished surface.
- D. high transmissivity of radiation. Discuss
Process Control and Instrumentation problems
Search Results
Correct Answer: 12, 0.6, 0.12
Correct Answer: all a, b & c.
Correct Answer: thermal conductivity cell
Correct Answer: e-?ss
Correct Answer: the maximum
Correct Answer: PI
Correct Answer: Bourdon tube
Correct Answer: both(b)&(c)
Correct Answer: Bare mercury in glass thermometer.
Correct Answer: high transmissivity of radiation.
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