Anna University Instrumentation and Control Systems Exam Paper
‘I’ime : 3 hours Max : 100 marks
PART – A Answer the following questions :- (10 x 2 = 20)
1. What do you mean by functional elements of a measuring instrument?
2.What is the significance of having null deflection?
3.Give any two examples for passive transducers.
4. State the applications of strain gauge.
5. State the difference between thermocouple and thermistors.
6.State the uses of counters and timers.
7.Mention two examples for an open loop control system.
8.Define transfer function of a system.
9.Define in brief the principle of operation of a taco generator.
10.State Mason’s gain formula.
PART-B Answer Five of the following questions:- (5×16= 80)
11. i)Discuss in detail about any two active and passive transducers. (8) ii) Explain in detail about “Null and Deflection methods”. (8)
12.A i)Write short notes on: Strain gauge (8)
ii) LVOT (4) iii) Induction Transducer (4)
12.B i) Discuss in detail about the methods for measuring displacement and force. (10)
ii) Explain in detail about a closed loop system with a practical example. (6)
13.A i) Derive the differential equations and transfer functions of a simple mechanical system
ii)Obtain the transfer function of an AC servomotor (8)
13.B i) Derive the necessary expressions for a 2nd order system with respect to time response. (8)
ii) Write down the rules for finding the stability of a system, using Root Locus Techniques. (8)
14.A i)Classify transducers with examples. (3)
ii) What are all the methods to measure humidity? (7)
iii) Explain LVDT (6)
14.B i)Define PDM recording. (3)
ii) Explain any two types of recorders. (7)
iii) Explain potentiometric type DVM. (6)
15.A i)Define transmittance. (2)
ii) Write down the rules for drawing signal flow graphs. (4)
iii) Draw the signal flow graph for the system whose block diagram as shown in figure. Determine the overall transmittance. (10)
15.B i)Define stability. (2)
ii)A closed loop control system has the characteristic equation given by (4)
S3 + 4.5 S2 + 3.5 S+1.5 = 0
Investigate the stability using Routh – Hurwitz Criterion.
iii) Using Routh – Hurwitz criterion determine the relation between KPT so that 10 unity feedback control system whose open loop transfer function given below is stable G (S) = k/ S[S(S+10)+T]
And determine the modified relation between k and T if all the roots of characteristic equation as determined above are to lie to the left of the line S = -1 in S – plane. (10)