Measurement and Instrumentation: Theory and Application

Measurement and Instrumentation
Copyright
Preface
1. Fundamentals of measurement systems
	1.1 Introduction
	1.2 Measurement units
	1.3 Measurement system design
		1.3.1 Elements of a measurement system
		1.3.2 Choosing appropriate measuring instruments
	1.4 Measurement system applications
	1.5 Summary
	1.6 Problems
2. Instrument types and performance characteristics
	2.1 Introduction
	2.2 Review of instrument types
		2.2.1 Active and passive instruments
		2.2.2 Null-type and deflection-type instruments
		2.2.3 Analog and digital instruments
		2.2.4 Indicating instruments and instruments with a signal output
		2.2.5 Smart and nonsmart instruments
	2.3 Static characteristics of instruments
	2.4 Dynamic characteristics of instruments
		2.4.1 Zero-order instrument
		2.4.2 First-order instrument
		2.4.3 Second-order instrument
	2.5 Necessity for calibration
	2.6 Summary
	2.7 Problems
3. Measurement uncertainty
	3.1 Introduction
	3.2 Sources of systematic error
		3.2.1 System disturbance due to measurement
			Measurements in electric circuits
		3.2.2 Errors due to environmental inputs
		3.2.3 Wear in instrument components
		3.2.4 Connecting leads
	3.3 Reduction of systematic errors
	3.4 Quantification of systematic errors
		3.4.1 Quantification of individual systematic error components
			Environmental condition errors
			Calibration errors
			System disturbance errors
			Measurement system loading errors
		3.4.2 Calculation of overall systematic error
	3.5 Sources and treatment of random errors
	3.6 Induced measurement noise
		3.6.1 Inductive coupling
		3.6.2 Capacitive (electrostatic) coupling
		3.6.3 Noise due to multiple earths
		3.6.4 Noise in the form of voltage transients
		3.6.5 Thermoelectric potentials
		3.6.6 Shot noise
		3.6.7 Electrochemical potentials
	3.7 Techniques for reducing induced measurement noise
		3.7.1 Location and design of signal wires
		3.7.2 Earthing
		3.7.3 Shielding
		3.7.4 Other techniques
	3.8 Summary
	3.9 Problems
4. Statistical analysis of measurements subject to random errors
	4.1 Introduction
	4.2 Mean and median values
	4.3 Standard deviation and variance
	4.4 Graphical data analysis techniques: frequency distributions
	4.5 Gaussian (Normal) distribution
	4.6 Standard Gaussian tables (z distribution)
	4.7 Standard error of the mean
	4.8 Estimation of random error in a single measurement
	4.9 Distribution of manufacturing tolerances
	4.10 Chi-squared (χ2) distribution
	4.11 Goodness of fit to a Gaussian distribution
		4.11.1 Inspecting shape of histogram
		4.11.2 Using a normal probability plot
		4.11.3 Chi-squared test
	4.12 Rogue data points (data outliers)
	4.13 Student t distribution
	4.14 Aggregation of measurement system errors
		4.14.1 Combined effect of systematic and random errors
		4.14.2 Aggregation of errors from separate measurement system components
			Error in a sum
			Error in a difference
			Error in a product
			Error in a quotient
		4.14.3 Total error when combining multiple measurements
	4.15 Summary
	4.16 Problems
5. Calibration of measuring sensors and instruments
	5.1 Introduction
	5.2 Principles of calibration
	5.3 Control of calibration environment
	5.4 Calibration chain and traceability
	5.5 Calibration records
	5.6 Summary
	5.7 Problems
	References
6. Conversion of nonvoltage sensor outputs
	6.1 Introduction
	6.2 Resistance measurement using a direct current bridge circuit
		6.2.1 Null-type, direct current bridge (Wheatstone bridge)
		6.2.2 Deflection-type direct current bridge
			Case where current drawn by measuring instrument is not negligible
		6.2.3 Error analysis
			Apex balancing
	6.3 Impedance measurement using alternating current bridges
		6.3.1 Null-type impedance bridge
		6.3.2 Maxwell and Hay's bridges
		6.3.3 Deflection-type alternating current bridge
	6.4 Alternative methods for measuring resistance
		6.4.1 Voltmeter-ammeter method
		6.4.2 Resistance-substitution method
		6.4.3 Measurement using a digital voltmeter
		6.4.4 Measurement using an ohmmeter
	6.5 Alternative method for measuring inductance
	6.6 Alternative methods to measure capacitance
	6.7 Current measurement
	6.8 Frequency measurement
		6.8.1 Measurement using a digital counter-timer
		6.8.2 Measurement using a phase-locked loop
		6.8.3 Measurement using an oscilloscope
		6.8.4 Measurement using a Wien bridge
	6.9 Phase measurement
		6.9.1 Measurement using an electronic counter-timer
		6.9.2 Measurement using an X–Y plotter
		6.9.3 Measurement using an oscilloscope
		6.9.4 Measurement using a phase-sensitive detector
	6.10 Summary
	6.11 Problems
7. Measurement signal transmission
	7.1 Introduction
	7.2 Analog transmission using copper conductors
		7.2.1 Transmission as varying voltages
		7.2.2 Current loop transmission
		7.2.3 Transmission using an A.C. carrier
	7.3 Digital transmission using copper conductors
	7.4 Fiber-optic transmission
		7.4.1 Principles of fiber optics
		7.4.2 Transmission characteristics
		7.4.3 Multiplexing schemes
	7.5 Optical wireless telemetry (open air path transmission)
	7.6 Radio telemetry (radio wireless transmission)
	7.7 Pneumatic transmission
	7.8 Summary
	7.9 Problems
8. Principles of data acquisition and signal processing
	8.1 Introduction
	8.2 Preliminary definitions
	8.3 Sensor signal characteristics
	8.4 Aliasing
	8.5 Quantization
	8.6 Analog signal processing
	8.7 Passive filters
		8.7.1 Filter transfer function
		8.7.2 Low-pass filter bode plot
		8.7.3 Passive high-pass filter
	8.8 Active filters
		8.8.1 Active low-pass filter
		8.8.2 Signal amplification
		8.8.3 Noninverting amplifier
		8.8.4 Differential amplification
		8.8.5 Instrumentation amplifier
		8.8.6 Other op-amp based filters and amplifiers
	8.9 Digital filters
		8.9.1 Filter with memory
		8.9.2 Example
		8.9.3 ARMA and IIR filters
	8.10 Summary
	8.11 Exercises
	Appendix
		Simple filter solution
9. Use of LabVIEW in data acquisition and postprocessing of signals
	9.1 Introduction
	9.2 Computer-based data acquisition
	9.3 Acquisition of data
	9.4 National instruments LabVIEW
		Virtual instruments
	9.5 Introduction to graphical programming in LabVIEW
	9.6 Elements of the tools palette
	9.7 Logic operations in LabVIEW
	9.8 Loops in LabVIEW
	9.9 Case structures in LabVIEW
	9.10 Data acquisition using LabVIEW
	9.11 LabVIEW function generation
	9.12 LabVIEW implementation of digital filters
	9.13 Higher-order digital filters in LabVIEW
	9.14 Summary
	9.15 Exercises
10. Display, recording and presentation of measurement data
	10.1 Introduction
	10.2 Display of measurement signals
		10.2.1 Digital meters
		10.2.2 Analog meters
			Moving-coil meter
			Moving-iron meter
			Clamp-on meters
			Analog multimeter
			Measuring high-frequency signals with analog meters
			Calculation of meter outputs for nonstandard waveforms
		10.2.3 Oscilloscopes
			Analog oscilloscope (Cathode ray oscilloscope)
			Digital storage oscilloscopes
			Digital phosphor oscilloscope
			Digital sampling oscilloscope
			PC-based oscilloscope
		10.2.4 Electronic output displays
		10.2.5 Computer monitor displays
	10.3 Recording of measurement data
		10.3.1 Chart recorders
			Pen strip chart recorder
			Multipoint strip chart recorder
			Circular chart recorder
			Paperless chart recorder
			Videographic recorder
		10.3.2 Ink-jet and laser printers
		10.3.3 Other recording instruments
		10.3.4 Digital data recorders
	10.4 Presentation of data
		10.4.1 Tabular data presentation
		10.4.2 Graphical presentation of data
			Fitting curves to data points on a graph
			Regression techniques
			Linear least squares regression
			Quadratic least squares regression
			Polynomial least squares regression
			Confidence tests in curve fitting by least squares regression
			Correlation tests
	10.5 Summary
	10.6 Problems
11. Intelligent sensors
	11.1 Introduction
	11.2 Principles of digital computation
		11.2.1 Elements of a computer
		11.2.2 Computer operation
			Programming and program execution
		11.2.3 Computer input–output interface
			Address decoding
			Data transfer control
		11.2.4 Practical considerations in adding computers to measurement systems
	11.3 Intelligent devices
		11.3.1 Intelligent instruments
		11.3.2 Smart sensors
			Calibration capability
			Self-diagnosis of faults
			Automatic calculation of measurement accuracy and compensation for random errors
			Adjustment for measurement nonlinearities
		11.3.3 Smart transmitters
			Comparison of performance with other forms of transmitter
			Summary of advantages of smart transmitters
			Self-calibration
			Self-diagnosis and fault detection
	11.4 Communication with intelligent devices
		11.4.1 Input–output interface
		11.4.2 Parallel data bus
		11.4.3 Local area networks
			Star networks
			Ring and bus networks
		11.4.4 Digital fieldbuses
	11.5 Summary
	11.6 Problems
	References
12. Measurement reliability and safety systems
	12.1 Introduction
	12.2 Reliability
		12.2.1 Principles of reliability
			Reliability quantification in quasiabsolute terms
			Failure patterns
			Reliability quantification in probabilistic terms
		12.2.2 Laws of reliability in complex systems
			Reliability of components in series
			Reliability of components in parallel
		12.2.3 Improving measurement system reliability
			Choice of instrument
			Instrument protection
			Regular calibration
			Redundancy
		12.2.4 Software reliability
			Quantifying software reliability
			Improving software reliability
	12.3 Safety systems
		12.3.1 Introduction to safety systems
			IEC61508
		12.3.2 Design of a safety system
			Two-out-of-three voting system
			Standby system
			Actuators and alarms
	12.4 Summary
	12.5 Problems
	References
13. Sensor technologies
	13.1 Introduction
	13.2 Capacitive sensors
	13.3 Resistive sensors
	13.4 Magnetic sensors
	13.5 Hall-effect sensors
	13.6 Piezoelectric transducers
	13.7 Strain gauges
	13.8 Piezoresistive sensors
	13.9 Optical sensors
		13.9.1 Optical sensors (Air-path)
			Light sources
			Light detectors
		13.9.2 Optical sensors (Fiber-optic)
			Intrinsic sensors
			Extrinsic sensors
			Distributed sensors
	13.10 Ultrasonic transducers
		13.10.1 Transmission speed
		13.10.2 Directionality of ultrasound waves
		13.10.3 Relationship between wavelength, frequency and directionality of ultrasound waves
		13.10.4 Attenuation of ultrasound waves
		13.10.5 Ultrasound as a range sensor
			Measurement resolution and accuracy
		13.10.6 Effect of noise in ultrasonic measurement systems
		13.10.7 Exploiting Doppler shift in ultrasound transmission
	13.11 Nuclear sensors
	13.12 Microsensors (MEMS sensors)
	13.13 Nanosensors (NEMS sensors)
	13.14 Summary
	13.15 Problems
	Reference
14. Temperature measurement
	14.1 Introduction
	14.2 Thermoelectric effect sensors (thermocouples)
		14.2.1 Thermocouple tables
		14.2.2 Nonzero reference junction temperature
		14.2.3 Thermocouple types
			Base metal thermocouples
			Noble metal thermocouples
		14.2.4 Thermocouple protection
		14.2.5 Thermocouple manufacture
		14.2.6 The thermopile
		14.2.7 Digital thermometer
		14.2.8 The continuous thermocouple
	14.3 Varying-resistance devices
		14.3.1 Resistance temperature device (resistance thermometer)
		14.3.2 Thermistors
	14.4 Semiconductor devices
	14.5 Radiation thermometers
		14.5.1 Optical pyrometer
		14.5.2 Radiation pyrometers
	14.6 Thermography (thermal imaging)
	14.7 Thermal expansion methods
		14.7.1 Liquid-in-glass thermometers
		14.7.2 Bimetallic thermometer
		14.7.3 Pressure thermometers
	14.8 Fiber-optic temperature sensors
	14.9 Color indicators
	14.10 Pyrometric cones
	14.11 Intelligent temperature-measuring instruments
	14.12 Microelectromechanical system temperature sensors
	14.13 Choice between temperature transducers
	14.14 Calibration of temperature transducers
		14.14.1 Reference instruments and special calibration equipment
		14.14.2 Calculating frequency of calibration checks
		14.14.3 Procedures for calibration
	14.15 Summary
	14.16 Problems
15. Pressure measurement
	15.1 Introduction
	15.2 Diaphragms
	15.3 Capacitive pressure sensor
	15.4 Fiber-optic pressure sensors
	15.5 Bellows
	15.6 Bourdon tube
	15.7 Manometers
	15.8 Resonant-wire devices
	15.9 Digital pressure gauges
		15.9.1 Piezoresistive digital pressure gauge
		15.9.2 Piezoelectric digital pressure gauge
		15.9.3 Magnetic digital pressure gauge
		15.9.4 Capacitive digital pressure gauge
		15.9.5 Fiber-optic digital pressure sensor
		15.9.6 Potentiometric digital pressure sensor
		15.9.7 Resonant-wire digital pressure transducer
	15.10 MEMS pressure sensors
	15.11 Special measurement devices for low-pressures
	15.12 High-pressure measurement (greater than 7000bar)
	15.13 Intelligent pressure transducers
	15.14 Differential pressure measuring devices
	15.15 Selection of pressure sensors
	15.16 Calibration of pressure sensors
		15.16.1 Reference calibration instruments
			Dead-weight gauge (pressure balance)
			U-tube manometer
			Barometers
			Vibrating cylinder gauge
			Gold-chrome alloy resistance instruments
			McLeod gauge
			Ionization gauge
			Micromanometers
		15.16.2 Calculating frequency of calibration checks
		15.16.3 Procedures for calibration
	15.17 Summary
	15.18 Problems
16. Flow measurement
	16.1 Introduction
	16.2 Mass flow rate
		16.2.1 Conveyor-based methods
		16.2.2 Coriolis flowmeter
		16.2.3 Thermal mass flow measurement
		16.2.4 Joint measurement of volume flow rate and fluid density
	16.3 Volume flow rate
		16.3.1 Differential pressure (obstruction-type) meters
			Orifice plate
			Venturis and similar devices
			Pitot static tube
		16.3.2 Variable area flowmeters (Rotameters)
		16.3.3 Positive displacement flowmeters
		16.3.4 Turbine meters
		16.3.5 Electromagnetic flowmeters
		16.3.6 Vortex-shedding flowmeters
		16.3.7 Ultrasonic flowmeters
			Doppler shift ultrasonic flowmeter
			Transit-time ultrasonic flowmeter
			Combined Doppler-shift/transit time flowmeters
		16.3.8 Other types of flowmeter for measuring volume flow rate
		16.3.9 Open channel flowmeters
	16.4 Intelligent flowmeters
	16.5 Choice between flowmeters for particular applications
	16.6 Calibration of flowmeters
		16.6.1 Calibration equipment and procedures for mass flow measuring instruments
		16.6.2 Calibration equipment and procedures for instruments measuring the volume flow rate of liquids
			Calibrated tank
			Gravimetric method
			Pipe prover
			Compact prover
			Positive displacement meter
			Orifice plate
			Turbine meter
		16.6.3 Calibration equipment and procedures for instruments measuring the volume flow rate of gases
			Bell prover
			Positive displacement meter
			Compact prover
		16.6.4 Reference standards
	16.7 Summary
	16.8 Problems
17. Level measurement
	17.1 Introduction
	17.2 Dipsticks
	17.3 Float systems
	17.4 Pressure-measuring devices (Hydrostatic systems)
	17.5 Capacitive devices
	17.6 Ultrasonic level gauge
	17.7 Radar (microwave) sensors
	17.8 Nucleonic (or radiometric) sensors
	17.9 Vibrating level sensor
	17.10 Intelligent level-measuring instruments
	17.11 Choice between different level sensors
	17.12 Calibration of level sensors
	17.13 Summary
	17.14 Problems
18. Mass, force, and torque measurement
	18.1 Introduction
	18.2 Mass (weight) measurement
		18.2.1 Electronic load cell (Electronic balance)
		18.2.2 Pneumatic and Hydraulic load cells
		18.2.3 Intelligent load cells
		18.2.4 Mass balance (Weighing) instruments
		18.2.5 Spring balance
	18.3 Force measurement
		18.3.1 Use of accelerometers
		18.3.2 Vibrating wire sensor
		18.3.3 Use of load cells
	18.4 Torque measurement
		18.4.1 Measurement of induced strain
		18.4.2 Optical torque measurement
		18.4.3 Torque measurement using surface acoustic wave MEMS devices
	18.5 Calibration of mass, force and torque measuring sensors
		18.5.1 Mass calibration
			Beam balance
			Weigh beam
			Electromagnetic balance
			Proof-ring-based load cell
		18.5.2 Force sensor calibration
		18.5.3 Calibration of torque-measuring systems
	18.6 Summary
	18.7 Problems
	Reference
19. Translational motion, vibration, and shock measurement
	19.1 Introduction
	19.2 Displacement
		19.2.1 Resistive potentiometer
		19.2.2 Linear variable differential transformer
		19.2.3 Variable capacitance transducers
		19.2.4 Variable inductance transducers
		19.2.5 Strain gauges and piezoresistive sensors
		19.2.6 Piezoelectric transducers
		19.2.7 Nozzle flapper
		19.2.8 Other methods of measuring small- to medium-sized displacements
			Linear inductosyn
			Translation of linear displacements into rotary motion
			Integration of output from velocity transducers and accelerometers
			Laser interferometer
			Fotonic sensor
			Noncontacting optical sensor
		19.2.9 Measurement of large displacements (range sensors)
			Energy source/detector-based range sensors
			Rotary potentiometer and spring-loaded drum
		19.2.10 Proximity sensors
		19.2.11 Choosing translational measurement transducers
		19.2.12 Calibration of translational displacement measurement transducers
	19.3 Velocity
		19.3.1 Differentiation of displacement measurements
		19.3.2 Integration of the output of an accelerometer
		19.3.3 Conversion to rotational velocity
		19.3.4 Calibration of velocity measurement systems
	19.4 Acceleration
		19.4.1 Selection of accelerometers
		19.4.2 Calibration of accelerometers
	19.5 Vibration
		19.5.1 Nature of vibration
		19.5.2 Vibration measurement
		19.5.3 Calibration of vibration sensors
	19.6 Shock
		19.6.1 Calibration of shock sensors
	19.7 Summary
	19.8 Problems
20. Rotational motion transducers
	20.1 Introduction
	20.2 Rotational displacement
		20.2.1 Circular and helical potentiometers
		20.2.2 Rotational variable differential transformer
		20.2.3 Incremental shaft encoders
		20.2.4 Coded-disk shaft encoders
			Optical digital shaft encoder
			Contacting (electrical) digital shaft encoder
			Magnetic digital shaft encoder
		20.2.5 The resolver
			Varying amplitude output resolver
			Varying phase output resolver
		20.2.6 The synchro
		20.2.7 The rotary inductosyn
		20.2.8 Gyroscopes
			Mechanical gyroscopes
			Optical gyroscopes
		20.2.9 Choice between rotational displacement transducers
		20.2.10 Calibration of rotational displacement transducers
	20.3 Rotational velocity
		20.3.1 Digital tachometers
			Optical sensing
			Inductive sensing
			Magnetic (Hall-effect) sensing
		20.3.2 Stroboscopic methods
		20.3.3 Analog tachometers
		20.3.4 The rate gyroscope
		20.3.5 Fiber-optic gyroscope
		20.3.6 MEMS gyroscope
		20.3.7 Differentiation of angular displacement measurements
		20.3.8 Integration of the output from an accelerometer
		20.3.9 Choice between rotational velocity transducers
		20.3.10 Calibration of rotational velocity transducers
	20.4 Rotational acceleration
		20.4.1 Calibration of rotational accelerometers
	20.5 Summary
	20.6 Problems
21. Summary of other measurements
	21.1 Introduction
	21.2 Dimension measurement
		21.2.1 Rules and tapes
		21.2.2 Calipers
		21.2.3 Micrometers
		21.2.4 Gauge blocks (slip gauges) and length bars
		21.2.5 Height and depth measurement
		21.2.6 Calibration of dimension measurements
	21.3 Angle measurement
		21.3.1 Calibration
	21.4 Surface flatness measurement
		21.4.1 Calibration of variation gauge
	21.5 Volume measurement
		21.5.1 Calibration of volume measurements
	21.6 Viscosity measurement
		21.6.1 Viscosity calibration
	21.7 Moisture measurement
		21.7.1 Industrial moisture measurement techniques
			Electrical methods
			Neutron moderation
			Low-resolution nuclear magnetic resonance
			Optical methods
			Ultrasonic methods
			Change in mechanical properties
		21.7.2 Laboratory techniques for moisture measurement
			Water separation
			Gravimetric methods
			Phase-change methods
			Equilibrium relative humidity measurement
		21.7.3 Humidity measurement
			The electrical hygrometer
			The psychrometer (wet and dry bulb hygrometer)
			Dew point meter
			Microelectromechanical system (MEMS)relative humidity sensor
		21.7.4 Calibration of moisture and humidity measurements
	21.8 Sound measurement
		21.8.1 Calibration of sound meters
	21.9 pH measurement
		21.9.1 pH calibration
	21.10 Gas sensing and analysis
		21.10.1 Calibration of gas sensors
	21.11 Summary
	21.12 Problems
Appendix 1 Imperial–metric–SI conversion tables
	Length
	Area
	Second moment of area
	Volume
	Density
	Mass
	Force
	Torque (moment of force)
	Inertia
	Pressure
	Additional conversion factors
	Energy, work, heat
	Additional conversion factors
	Power
	Velocity
	Acceleration
	Mass flow rate
	Volume flow rate
	Specific energy (heat per unit volume)
	Dynamic viscosity
	Kinematic viscosity
Appendix 2 Thévenin's theorem
	References
Appendix 3 Thermocouple tables
Appendix 4 Using mathematical tables
	Interpolation
Index
	A
	B
	C
	D
	E
	F
	G
	H
	I
	J
	K
	L
	M
	N
	O
	P
	Q
	R
	S
	T
	U
	V
	W
	X
	Z