EXPERT SYSTEMS AND SOLUTIONS Email: expertsyssol@gmail expertsyssol@yahoo Cell: 9952749533

1. EXPERT SYSTEMS AND SOLUTIONS Email: expertsyssol@gmail.com expertsyssol@yahoo.com Cell: 9952749533 www.researchprojects.info PAIYANOOR, OMR, CHENNAI Call For Research Projects Final year students of B.E in EEE, ECE, EI, M.E (Power Systems), M.E (Applied Electronics), M.E (Power Electronics) Ph.D Electrical and Electronics. Students can assemble their hardware in our Research labs. Experts will be guiding the projects.

2. EI1361-MEASUREMENT AND INSTRUMENTATION -C.KAMALA KANNAN Lecturer/EEE

3. UNIT 5 TRANSDUCERS AND DATA ACQUISITION SYSTEMS

4. TRANSDUCERS AND DATA ACQUISITION SYSTEMS • Classification of transducers • Selection of transducers • Resistive transducers • Capacitive transducers • Inductive transducers • Piezoelectric transducers • Optical transducers • Digital transducers • Elements of data acquisition system - A/D, D/A converters.

5. Reference TEXT BOOKS • 1. E.O. Doebelin, ‘Measurement Systems – Application and Design’, Tata McGraw Hill publishing company, 2003. • 2. A.K. Sawhney, ‘A Course in Electrical & Electronic Measurements & Instrumentation’, Dhanpat Rai and Co, 2004.

6. REFERENCE BOOKS 1. A.J. Bouwens, ‘Digital Instrumentation’, Tata McGraw Hill, 1997. 2. D.V.S. Moorthy, ‘Transducers and Instrumentation’, Prentice Hall of India Pvt Ltd, 2003. 3. H.S. Kalsi, ‘Electronic Instrumentation’, Tata McGraw Hill, 1995. 4. Martin Reissland, ‘Electrical Measurements’, New Age International (P) Ltd., Delhi, 2001. 5. J. B. Gupta, ‘A Course in Electronic and Electrical Measurements’, S. K. Kataria & Sons, Delhi, 2003.

7. TRANSDUCERS • It’s a device which convert one form of energy to another form • Non electrical quantity is converted into an electrical form by a transducer. • Another name is pick up

8. Advantage of Electrical Transducers • Electrical amplification and attenuation can be done easily. • Mass inertia effects are minimized. • The effect of friction is minimized. • The electrical or electronic systems can be controlled with a very small power level.

9. Conti.. • The electrical output can be easily used , transmitted and processed for the purpose of measurement. • Telemetry (aerospace – remote indication / recording) • Miniaturization on account of use of IC’s.

10. Two parts/element of transducer • Sensing or detector element. A detector or a sensing element is that part of a transducer which responds to a physical phenomenon or a change in a physical phenomenon. • Transduction element. A transduction element transforms the output of a sensing element to an electrical output. The transduction element in a way acts as a secondary transducer.

11. Classification of Transducers • On the basis of transduction form used. • As primary and secondary transducers • As passive and active transducer. • As analog and digital transducer. • As transducers and inverse transducers.

12. Classification based upon principle of transduction • Resistive • Inductive • Capacitive etc Depending upon how they convert the input quantity into resistance, inductance or capacitance respectively. Eg piezoelectric, thermoelectric, magneto restrictive, electro kinetic and optical

13. Primary and Secondary Transducers LVDT (Linear Variable Differential Transformer) • Primary- Pressure to displacement (bourdon tube) • Secondary-Displacement into analogous voltage (LVDT).

14. Passive and Active Transducer • Active Transducer: Also known as self generating type, develop their own voltage or current from the physical phenomenon being measured. Velocity , temperature , light intensity and force can be transduced with the help of active transducer.

15. Conti.. • Passive Transducer: Also known as externally powered transducers, i.e., derive the power required for energy conversion from an external power source. e.g. POT (Potentiometer)-used for the measurement of displacement .

16. Analog and Digital Transducer. • Analog Transducers : It converts the input quantity into an analog output which is a continuous function of time. • E.g. LVDT, Thermocouple or a thermistor (gives output which is continuous function of time)

17. Conti.. • Digital Transducer: Converts input quantity into an electrical output which is in the form of pulse.

18. Transducers and Inverse Transducers • Transducer: Non electrical to electrical quantity • Inverse transducer: Electrical quantity into non electrical quantity.

19. Characteristics and Choice of Transducer • Input Characteristics • Transfer Characteristics • Output Characteristics.

20. Input Characteristics • Type of Input and Operating Range • Loading effect. • Type of Input :The type of input, which can be any physical quantity, is generally determined in advance . • Operating Range : Choice of transducer depends upon the useful range of input quantity.

21. Conti.. • Loading Effect : The transducer, that is selected for a particular application should ideally exact NO force, power or energy from the quantity under measurement in order that is measured accurately.

22. Transfer Characteristics • Transfer function. • Error. • Response of transducer to environmental influences.

23. Transfer function. • The transfer function of a transducer defines a relationship between the input quantity and the output. The transfer function is Where are respectively output and input of the transducer.

24. Conti.. • Sensitivity, • Scale Factor, Inverse of sensitivity.

25. Error • The error in transducer occur because they do not follow, the input output relationship. • Example.. Instead of qo, we might get a output as qo’, then the error of the instrument is

26. Three components of error • Scale error. • Dynamic error • Error on account of noise and drift.

27. Scale error. • Zero error. • Sensitivity error • Non conformity. • Hysteresis.

28. Practical Curve.  Output Theorectical Curve. Input Zero error • Output deviates from the correct value by a constant factor over the entire range of the transducer.

29. Practical Curve.  Output Theorectical Curve. Input Sensitivity Error • Observed output deviates from the correct value by a constant value.

30. Practical Curve.  Output Theorectical Curve. Input Non conformity • Transfer function deviates from the theoretical transfer function for almost every input.

31. Decreasing input Output Increasing input Input Hysteresis

32. Response of transducer to environmental influences. • It should not be subjected to any disturbances like stray electromagnetic and electrostatic fields, mechanical shocks and vibrations temperature changes, pressure and humidity changes, changes in supply voltage and improper mechanical mountings.

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