Anna University Chennai 2005 B.Tech Process Control Systems - Question Paper

PART A - (10*2= 20 marks)

01. Write the effect of Time delay in process control systems.
02. Write the transfer function of proportional Integral control.
03. What is the difference ranging from interacting and non-interacting systems.
04. Define the decay ratio of Under-damped systems.
05. What are the major components of process control systems.
06. Define phase cross over frequency in bode stability criterion.
07. Draw the block diagram of a control loop for a measurement of process reaction curve.
08. Describe the function of a control valve.
09. Write about any 2 factors involved in a selection of a control valve.
10.Define the flow co-efficient of the control valve.


PART – B (5 * 16 = 80 marks)
11. i) discuss the term degree of freedom of a process.
ii) In a stirred tank heater systems shown in fig. The flow rate of the effluent system is proportional to the square root of the liquid level in the tank. find the relation ranging from the change outflow temperature for change in inflow temperature. Assuming the inflow, outflow and steam temperature are constant.

12. a) i) Bring out the relative advantages and disadvantages of Proportional, Integral and Derivative control actions (8)
ii) discuss the characteristics of PI controller on the closed loop response of a 1st order process for unit step change in setpoint and load.(8)
Or
b) i) What is meant by bumpless transfer? (7)
ii) explain about the factors to e considered while selecting the kind of controller for different process. (9)

13. a) i) define the valuation criteria of integrals of the square, absolute value and time-weighted absolute errors of the controller settings. (10)
ii) provide the optimum controller settings for the model
G(s) =e-0.5s/4s+1 found by reaction curve method. (6)
OR
b) explain about the controller settings using Ziegler-Nichols continuous
cycling method and write its limitations. (16)

14. a) I) What is meant by feed forward control (4)
II) Why it is preferred along with feedback control (4)
III) discuss the feed forward control strategy for a typical process(8)
OR
b) I) define the control loops in an exothermic reactor. (8)
II) discuss the role of induced draft fan and forced draft fan in the combustion of fuel in a boiler (8)

15. a) I) What is the need for a valve positioner? ( 4)
II) List the factors that decid the lag in a pneuatic transmission line (4)
III) define the working of a pneumatic actuator with positioner (8)
OR
b) I) define the construction of control valve (8)
II) discuss what is cavitation and flashing in control valves (8)

Earning:   Approval pending.