JNTU B.Tech II Semester Examinations, INSTRUMENTATION AND CONTROL SYSTEM, Apr/May 2008
Time: 3 hours Max Marks: 80
Answer any FIVE Questions
All Questions carry equal marks
1. (a) Classify measuring instruments.
(b) What are desired, modifying and interfering inputs for a measurement system?
Give examples for each of these quantities. What is the influence of these on the final output? [6+10]
2. (a) List electrical transducers for measurement of linear and angular displacement.
(b) Explain by means of neat sketches how wire wound and carbon film potentiometers can be used for measurement if linear and angular displacement. [4+12]
3. (a) Discuss various types of elastic pressure sensing elements used in electrical Transducers.
(b) Describe the application, advantages and limitations of elastic diaphragm gauges. [10+6]
4. Show that there exists a linear relation ship between the volume flow rate and displacement of float in the case of a rotameter .Prove that if the density of the float material is made twice that of flowing fluid, the volume flow rate becomes independent of the density of the flowing fluid and compression is almost complete for all flows. 
5. With neat sketches explain the following:
(a) drag cup tachometer
(b) Tachogenerators [8 × 2 = 16]
6. (a) What do you understand by strain gauge rosettes and the need for them?
(b) Tree strain gauges in the form of a delta rosette were attached to a specimen to finds strain. The readings of three gauges are ?1=800, ?2=400, ?3=0. Determine the principal strains, principal stresses and the location of principal plane. Assume E=680 × 102N/mm2 and ? =0.33. [6+10]
7. (a) Why humidity is to be measured?
(b) Define the Psychometric terms.
i. Dry air
ii. Moist air
iii. Saturated air
iv. Absolute humidity
v. Relative humidity
vi. Dry bulb temperature
vii. Wet bulb temperature [2+14]
8. (a) What is the significance of block diagrams in control systems?
(b) Distinguish between Manual control system and Automatic control systems. [8+8]