Jawaharlal Nehru Technological University Hyderabad 2005-1st Sem B.Tech Applied Electronics and Instrumentation Code No: RR311004 Set No.1 IIIRegular s,- PROCESS CONTROL INSTRUMENTATIO

Code No: RR311004 Set No.1
III B.Tech. I Semester Regular Examinations, November -2005
PROCESS CONTROL INSTRUMENTATION
( Common to Electronics & Instrumentation Engineering and
Instrumentation & Control Engineering)
Time: three hours Max Marks: 80
ans any 5 ques.
All ques. carry equal marks
? ? ? ? ?
1. (a) A flow head formula has the formula q = hn. compute the resistance.
(b) A liquid storage device is spherical in shape. compute 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 outcomes in
i. a steady change in head
ii. a rate of change of head proportional to head? [4+4+8]
2. (a) Dierentiate ranging from a “Servo operation” and “Regulator operation”.
(b) provide a typical example for servo operation and discuss.
(c) discuss the regulator operation with an example. [4+6+6]
3. (a) Briefly explain the characteristics of proportional control mode. Mention the
kind of processes for which proportional controller is most suited.
(b) A proportional controller has a gain of 3. Plot the controller output for the
fault provided beneath figure1 if Po = 50%. (Po – controller output with no error)
[8+8]
Figure 1:
4. (a) Briefly discuss the principle of operation of a displacement kind pneumatic
PD controller. How the derivative time can be adjusted in this controller.
(b) Outline the design steps involved in developing an electronic PI controller.
[8+8]
5. (a) Show by sketches how proportional and reset action rates are to be deter-
mined. What is the eect 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. find the nature of the output pressure.
presume KC =0.1 kg/cm2 /cm. TR =1.2 min. and TD = 0.5 min. [10+6]
6. (a) discuss the principle of operation of a stepping motor and provide its sole as an
actuator.
(b) A hydraulic system uses pistons of diameter 2cm and 40cm. What force on
the small piston will raise a 500 kg mass. [10+6]
7. Write short notes on.
(a) Globe Valves
(b) Ball valves
(c) Louvers [6+6+4]
8. elaborate the main advantages and disadvantages of cascade control? For what
type of processes can you employ cascade control?

Earning:   Approval pending.