5. Measurement, Instrumentation and Control

5. Measurement, Instrumentation and Control

• 5.1 Measurement and Error

  • Static and dynamic errors

  • Bridge circuits: Maxwell Bridge, Schering Bridge, Wien Bridge

• 5.2 Transducers, Sensors and Signal Conditioning

  • Definitions and classification of transducers and sensors

  • Factors for transducer/sensor selection

  • Transducer Types:

    • Resistive, Capacitive, Inductive (LVDT)

  • Sensor Types for Measuring:

    • Position, Proximity, Motion

    • Pressure, Level, Flow

  • Specific Sensors:

    • Strain gauges and Load cells

    • Temperature: RTDs, Thermistors, Thermocouples, Thermopiles

    • Piezoelectric sensors

    • Photoconductive, Photodiode, Photovoltaic, Phototransistor sensors

  • Signal Conditioning:

    • Linearization, Signal conversion, Filtering, Impedance/power matching

  • Digital Signal Conditioning:

    • Digital-to-Analog (DAC) and Analog-to-Digital (ADC) converter types

    • Performance parameters and error sources

• 5.3 Electrical Measurements and Instruments

  • Instrument requirements: deflection, controlling, and damping systems

  • Permanent Magnet Moving Coil (PMMC) instruments

  • Instruments:

    • Voltmeters, Ammeters, Ohmmeters, Clamp-meters, Multimeters

    • Wattmeters, Energy meters, Time-of-day meters

    • Power factor, Frequency, and Phase meters

  • Instrument transformers (CT, PT)

  • Megger and Tachometer

• 5.4 System Modeling

  • Control systems: definition and classification

  • Open-loop vs. closed-loop (feedback) systems

  • Modeling of:

    • Mechanical systems

    • Electrical systems

    • Liquid level systems

    • Thermal systems

  • Force-voltage and force-current analogies

  • Modeling of gears, transformers, sensors, encoders, generators

  • Modeling of electromechanical and mixed systems

• 5.5 Block Diagram Representation

  • Block diagram reduction rules and examples

  • Signal Flow Graph (SFG): definitions, construction rules, and conversions

  • Mixed system representation (block + SFG)

  • Time response of first-order and second-order systems to standard test signals

• 5.6 Stability Analysis

  • Definitions of stability

  • Routh-Hurwitz stability criterion

  • Root locus plot construction rules

  • Frequency Response Analysis:

    • Bode plots and stability assessment

    • Polar plots and Nyquist stability criterion

    • Gain margin and phase margin