ME-402 Instrumentation and Control - Jun 2022 Question Paper

Under each question, How to answer lists the points an answer should cover, outlined by CampusPrep from the syllabus. Check the details against your textbook.

1. 14 Marks
   Distinguish between the following

   1. i)Accuracy and Precision
   2. ii)Resolution and Threshold
   3. iii)Reproducibility and Repeatability
   4. iv)Dead zone and Hysteresis
   How to answer

   • Define each pair of metrological terms
   • Tabulate differences in meaning with examples
   • Explain effect on measurement performance
   • Give illustrative example for each term
2. 14 Marks
   What are the different sources of errors in measurements and measuring instruments? Explain them.
   How to answer

   • Define measurement errors
   • List gross, systematic and random error sources
   • Explain instrument, environmental, observational sources
   • Explain methods to minimize errors
3. 14 Marks
   Explain the following with neat sketches.

   1. i)Piezoelectric Transducer
   2. ii)Optical pyrometer
   3. iii)Photo electric transducer
   How to answer

   • State working principle of each transducer/device
   • Draw neat labelled sketch of construction
   • Explain operation and output
   • Mention applications
4. 7 Marks
   aDescribe the properties of materials used for piezoelectric transducers. Derive the expressions for voltage and charge sensitivities.
   How to answer

   • List piezoelectric materials: quartz, Rochelle salt, BaTiO3, PZT
   • Describe dielectric, coupling, stability properties
   • Derive charge $Q = d \cdot F$ and voltage $V = Q/C$ relations
   • Obtain voltage and charge sensitivity expressions
5. 7 Marks
   bCompare and contrast the advantages and limitations of resistance thermometers and thermistors.
   How to answer

   • State construction of RTD and thermistor
   • Compare sensitivity, range, linearity, stability
   • Compare cost, response and applications
   • Conclude advantages vs limitations table
6. 7 Marks
   aWhat are the mechanical tachometers? Explain with examples. Describe the disadvantages of these.
   How to answer

   • Define mechanical tachometer for speed measurement
   • Explain revolution counter, centrifugal, drag types with examples
   • Draw schematic of operation
   • List disadvantages: contact, inertia, wear, low frequency response
7. 7 Marks
   bExplain the different methods adopted for the calibration of accelerometers.
   How to answer

   • Define accelerometer calibration need
   • Explain static, dynamic and shake-table methods
   • Explain comparison and absolute calibration
   • Mention standards and procedure steps
8. 7 Marks
   aList the procedure to mount a strain gauge with paper backing on the surface under study.
   How to answer

   • List surface preparation and cleaning steps
   • Describe adhesive application and gauge placement
   • Explain curing, wiring and protection steps
   • Mention checks for mounting quality
9. 7 Marks
   bExplain the method of usage of resistance strain gauge for bending compressive and tensile strains.
   How to answer

   • State gauge factor and bridge arrangement
   • Explain placement for bending strain measurement
   • Explain arrangement for tensile vs compressive strain
   • Explain temperature compensation
10. 7 Marks
    aExplain how a sling psychrometer is used to determine the dry and the wet bulb temperatures.
    How to answer

    • Describe sling psychrometer construction with two thermometers
    • Explain whirling to get wet-bulb depression
    • Explain use of psychrometric chart/tables
    • Obtain dry-bulb and wet-bulb temperatures
11. 7 Marks
    bWith neat sketch explain the working principle of Strain gauge load cell.
    How to answer

    • Define load cell and strain gauge bridge
    • Draw neat sketch of column/proving-ring load cell with gauges
    • Explain load to strain to resistance to voltage conversion
    • Give output relation and applications
12. 14 Marks
    Write short notes the following:

    1. a)Servomechanism
    2. b)Temperature control system
    3. c)Position control system.
    How to answer

    • Define servomechanism with block diagram
    • Explain temperature control system loop
    • Explain position control system loop
    • Mention components and applications for each