Jawaharlal Nehru Technological University Hyderabad 2005-1st Sem B.Tech Applied Electronics and Instrumentation Code No: RR311004 Set No.4 IIIRegular s,- PROCESS CONTROL INSTRUMENTATIO

Code No: RR311004 Set No.4
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) Say whether heated tank and an immersed thermometer with negligible inter-
action is interacting or non-interacting. Justify your ans.
(b) Write the dierential equations and determine the transfer functions individ-
ually for heated tank and thermometer.
(c) Determine the overall transfer function of this combination. How is this trans-
fer function related with the individual transfer function? [3+9+4]
3. (a) explain the eects of an integral controller on the closed loop response of first
order process.
(b) With neat sketches, discuss the principle of derivative control action. Sum-
marize its characteristics. [8+8]
4. (a) define with a neat sketch, the principle of a force kind pneumatic PD con-
troller. Mention the merits of pneumatic controller.
(b) discuss with relevant equations, the implementation of the single mode control
action with electronic circuits. [8+8]
5. (a) What is meant by process tuning and list the different methods of tuning of
PID parameters.
(b) explain process reaction method for control loop tuning. [8+8]
6. discuss the principle of a direct and reverse pneumatic actuator. [16]
7. Write steps followed in choosing a valve for better control of flow and should be
cost eective. [16]
8. (a) discuss the principles of cascade controller tuning.
(b) State the fundamental dierence feed forward and conventional feed back con-
trol.
(c) Why is a process model needed for feed forward controller?

Earning:   Approval pending.