ei1202 measurements and – measurements and instrumentation ... ―a course in electrical and...

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  • LECTURE NOTES

    ON

    EI1202 MEASUREMENTS AND

    INSTRUMENTATION

    Ms.B.DEVI, L/ EEE

    N.P.R.

    COLLEGE OF ENGINEERING AND

    TECHNOLOGY,

    NATHAM.

  • SYLLABUS

    UNIT I FUNDAMENTALS

    Functional elements of an instrument Static and dynamic characteristics Errors in

    measurement Statistical evaluation of measurement data Standards and calibration

    UNIT II ELECTRICAL AND ELECTRONICS INSTRUMENTS

    Principle and types of analog and digital instruments Voltmeters Ammeters - Multimeters

    Single and three phase wattmeters and energy meters Magnetic measurements Determination

    of B-H curve and measurements of iron loss Instrument transformers Instruments for

    measurement of frequency and phase.

    UNIT III COMPARISON METHODS OF MEASUREMENTS

    D.C and A.C potentiometers D.C and A.C bridges Transformer ratio bridges Self-balancing

    bridges Interference and screening Multiple earth and earth loops Electrostatic and

    electromagnetic interference Grounding techniques.

    UNIT IV STORAGE AND DISPLAY DEVICES

    Magnetic disk and tape Recorders, digital plotters and printers CRT display Digital CRO,

    LED, LCD and dot-matrix display Data Loggers

    UNIT V TRANSDUCERS AND DATA ACQUISITION SYSTEMS

    Classification of transducers Selection of transducers Resistive, capacitive and inductive

    transducers Piezoelectric, optical and digital transducers Elements of data acquisition system

    A/D, D/A converters Smart sensors.

    TEXT BOOKS

    1. Doebelin, E.O., Measurement Systems Application and Design, Tata McGraw Hill

    Publishing Company, 2003.

    2. Sawhney, A.K., A Course in Electrical and Electronic Measurements and

    Instrumentation, Dhanpat Rai AND Co, 2004

    REFERENCES

    1. Bouwens, A.J., Digital Instrumentation, Tata McGraw Hill, 1997.

    2. Moorthy, D.V.S., Transducers and Instrumentation, Prentice Hall of India, 2007.

    3. Kalsi, H.S., Electronic Instrumentation, 2nd Edition, Tata McGraw Hill, 2004.

    4. Martin Reissland, Electrical Measurements, New Age International (P) Ltd., 2001.

    5. Gupta, J.B., A Course in Electronic and Electrical Measurements, S.K.Kataria and Sons,

    2003.

  • UNIT I FUNDAMENTALS

    Functional elements of an instrument Static and dynamic characteristics Errors

    in measurement Statistical evaluation of measurement data Standards and

    calibration

  • QUESTIONS

    FUNCTIONAL ELEMENTS OF AN INSTRUMENT PART A

    1. What are the functional elements of an instrument? (2)

    2. What is meant by accuracy of an instrument? (2)

    3. Define international standard for ohm? (2)

    4. What is primary sensing element? (2)

    5. What is calibration? (2)

    6. Define the terms precision & sensitivity. (2)

    7. What are primary standards? Where are they used? (2)

  • 8. When are static characteristics important? (2)

    9. What is standard? What are the different types of

    standards?(2)

    10. Define static error. Distinguish reproducibility and

    repeatability. (2)

    11. Distinguish between direct and indirect methods of

    measurements.

    12. With one example explain Instrumental Errors. (2)

    13. Name some static and dynamic characteristics. (2)

    14. State the difference between accuracy and precision of a

    measurement. (2)

    15. What are primary and secondary measurements? (2)

    16. What are the functions of instruments and measurement

    systems? (2)

    17. What is an error? How it is classified? (2)

    18. Classify the standards of measurement? (2)

    19. Define standard deviation and average deviation. (2)

    20. What are the sources of error? (2)

    21. Define resolution. (2)

    22. What is threshold? (2)

    23. Define zero drift. (2)

    24. Write short notes on systematic errors. (2)

    25. What are random errors? (2)

  • PART B

    1. Describe the functional elements of an instrument with its block

    diagram. And illustrate them with pressure gauge, pressure

    thermometer and DArsonval galvanometer. (16)

    2. (i) What are the three categories of systematic errors in the

    Instrument and explain in detail. (8)

    (ii) Explain the Normal or Gaussian curve of errors in the study

    Of random effects. (8)

    3. (i) What are the basic blocks of a generalized instrumentation

    system.

    Draw the various blocks and explain their functions. (10)

    (ii) Explain in detail calibration technique and draw the

    Calibration curve in general. (6)

    4. (i) Discuss in detail various types of errors associated in

    Measurement and how these errors can be minimized? (10)

    (ii) Define the following terms in the context of normal

    Frequency distribution of data (6)

    a) Mean value

    b) Deviation

    c) Average deviation

    d) Variance

    e) Standard deviation.

  • 5. (i) Define and explain the following static characteristics of an

    instrument. (8)

    a) Accuracy

    b) Resolution

    c) Sensitivity and

    d) Linearity

    (ii) Define and explain the types of static errors possible in an

    instrument. (8)

    6. Discuss in detail the various static and dynamic characteristics

    of a measuring system. (16)

    7. (i) For the given data, calculate

    a) Arithmetic mean

    b) Deviation of each value

    c) Algebraic sum of the deviations (6)

    X1 = 49.7, X2 = 50.1, X3 = 50.2, X4 = 49.6, X5 = 49.7

    (ii) Explain in detail the types of static error. (7)

    (iii) Give a note on dynamic characteristics. (3)

    8. (i) What is standard? Explain the different types of standards(8)

    (ii) What are the different standard inputs for studying the

    Dynamicresponse of a system. Define and sketch them. (8)

  • UNIT II ELECTRICAL AND ELECTRONICS INSTRUMENTS

    Principle and types of analog and digital instruments Voltmeters Ammeters -

    Multimeters Single and three phase wattmeters and energy meters Magnetic

    measurements Determinationof B-H curve and measurements of iron loss

    Instrument transformers Instruments formeasurement of frequency and phase.

    Principle and types of analog and digital instruments

    A multimeter ora multitester, also known as a volt/ohm meter or VOM, is

    an electronic measuring instrument that combines several measurement functions in one unit. A

    typical multimeter may include features such as the ability to

    measure voltage, current and resistance. Multimeters may use analogor digital circuitsanalog

    multimeters and digital multimeters (often abbreviated DMM or DVOM.) Analog instruments

    are usually based on amicroammeter whose pointer moves over a scale calibration for all the

    different measurements that can be made; digital instruments usually display digits, but may

    display a bar of a length proportional to the quantity measured.

    A multimeter can be a hand-held device useful for basic fault finding and field service work or

    a bench instrument which can measure to a very high degree of accuracy. They can be used to

    troubleshoot electrical problems in a wide array of industrial and household devices such

    as electronic equipment, motor controls, domestic appliances, power supplies, and wiring

    systems.

    Multimeters are available in a wide ranges of features and prices. Cheap multimeters can cost

    less than US$10, while the top of the line multimeters.

    http://en.wikipedia.org/wiki/Electronicshttp://en.wikipedia.org/wiki/Measuring_instrumenthttp://en.wikipedia.org/wiki/Voltagehttp://en.wikipedia.org/wiki/Electric_currenthttp://en.wikipedia.org/wiki/Electrical_resistancehttp://en.wikipedia.org/wiki/Analog_circuithttp://en.wikipedia.org/wiki/Digital_circuithttp://en.wikipedia.org/wiki/Microammeterhttp://en.wikipedia.org/wiki/Calibratedhttp://en.wikipedia.org/wiki/Faulthttp://en.wikipedia.org/w/index.php?title=Bench_instrument&action=edit&redlink=1http://en.wikipedia.org/wiki/Electronic_equipmenthttp://en.wikipedia.org/wiki/Domestic_appliancehttp://en.wikipedia.org/wiki/Power_supply

  • History

  • The first moving-pointer current-detecting device was the galvanometer. These were used to

    measure resistance and voltage by using a Wheatstone bridge, and comparing the unknown

    quantity to a reference voltage or resistance. While useful in the lab, the devices were very slow

    and impractical in the field. These galvanometers were bulky and delicate.

    The D'Arsonval/Weston meter movement used a fine metal spring to give proportional

    measurement rather than just detection, and built-in permanent field

    magnets made deflection independent of the 3D orientation of the meter. These features enabled

    dispensing with Wheatstone bridges, and made measurement quick and easy. By adding a series

    or shunt resistor, more than one range of voltage or current could be measured with one

    movement.

    Multimeters were invented in the early 1920s as radio receivers and other vacuum tube electronic

    devices became more common. The invention of the first multimeter is attribut

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