Measurement System

Download Measurement System

Post on 29-Oct-2015

1.579 views

Category:

Documents

3 download

Embed Size (px)

DESCRIPTION

Measurement System

TRANSCRIPT

<ul><li><p>Measurement SystemsApplication and Design</p><p>doe3886X_fm.qxd 4/14/2003 10:16 AM Page i</p></li><li><p>McGraw-Hill Series in Mechanical Engineering</p><p>Anderson: Computational Fluid Dynamics: The Basics with ApplicationsAnderson: Modern Compressible FlowBarber: Intermediate Mechanics of MaterialsBeer/Johnston: Vector Mechanics for EngineersBeer/Johnston/DeWolf: Mechanics of Materials Borman and Ragland: Combustion EngineeringBudynas: Advanced Strength and Applied Stress AnalysisCengel and Boles: Thermodynamics: An Engineering ApproachCengel and Turner: Fundamentals of Thermal-Fluid SciencesCengel: Heat Transfer: A Practical ApproachCengel: Introduction to Thermodynamics &amp; Heat TransferCondoor: Mechanical Design Modeling with ProENGINEERCourtney: Mechanical Behavior of MaterialsDieter: Engineering Design: A Materials &amp; Processing ApproachDieter: Mechanical MetallurgyDoebelin: Measurement Systems: Application &amp; DesignHamrock/Schmid/Jacobson: Fundamentals of Machine ElementsHeywood: Internal Combustion Engine FundamentalsHistand and Alciatore: Introduction to Mechatronics and Measurement SystemsHolman: Experimental Methods for EngineersHolman: Heat TransferHsu: MEMS &amp; Microsystems: Manufacture &amp; DesignKays and Crawford: Convective Heat and Mass TransferKelly: Fundamentals of Mechanical VibrationsKreider/Rabl/Curtiss The Heating and Cooling of BuildingsMattingly: Elements of Gas Turbine PropulsionNorton: Design of MachineryOosthuizen and Carscallen: Compressible Fluid FlowOosthuizen and Naylor: Introduction to Convective Heat Transfer AnalysisReddy: An Introduction to Finite Element MethodRibando: Heat Transfer ToolsSchey: Introduction to Manufacturing ProcessesSchlichting: Boundary-Layer TheoryShames: Mechanics of FluidsShigley and Mischke: Mechanical Engineering DesignStoecker: Design of Thermal SystemsTurns: An Introduction to Combustion: Concepts and ApplicationsUllman: The Mechanical Design ProcessWark: Advanced Thermodynamics for EngineersWark and Richards: ThermodynamicsWhite: Fluid MechanicsWhite: Viscous Fluid FlowZeid: CAD/CAM Theory and Practice</p><p>doe3886X_fm.qxd 4/14/2003 10:16 AM Page ii</p></li><li><p>Measurement SystemsApplication and Design</p><p>Fifth Edition</p><p>Ernest O. DoebelinDepartment of Mechanical EngineeringThe Ohio State University</p><p>doe3886X_fm.qxd 4/14/2003 10:16 AM Page iii</p></li><li><p>MEASUREMENT SYSTEMS: APPLICATION AND DESIGN, FIFTH EDITIONPublished by McGraw-Hill, a business unit of The McGraw-Hill Companies, Inc., 1221 Avenue ofthe Americas, New York, NY 10020. Copyright 2004, 1990, 1983, 1975, 1966 by The McGraw-HillCompanies, Inc. All rights reserved. No part of this publication may be reproduced or distributed in anyform or by any means, or stored in a database or retrieval system, without the prior written consent ofThe McGraw-Hill Companies, Inc., including, but not limited to, in any network or other electronicstorage or transmission, or broadcast for distance learning.Some ancillaries, including electronic and print components, may not be available to customers outside theUnited States.This book is printed on acid-free paper.1 2 3 4 5 6 7 8 9 0 DOC/ DOC 0 9 8 7 6 5 4 3ISBN 007243886XPublisher: Elizabeth A. JonesSponsoring editor: Jonathan PlantAdministrative assistant: Rory SteinMarketing manager: Sarah MartinLead project manager: Jill R. PeterSenior production supervisor: Laura FullerLead media project manager: Judi DavidSenior coordinator of freelance design: Michelle D. WhitakerCover designer: Joanne SchoplerCover concept: Ernest O. Doebelin; computer image: Photodisc, Global Communications, Vol. 64Senior photo research coordinator: Lori HancockCompositor: GACIndianapolisTypeface: 10/12 TimesPrinter: R. R. Donnelley Crawfordsville, IN</p><p>Library of Congress Cataloging-in-Publication DataDoebelin, Ernest O.</p><p>Measurement systems : application and design / Ernest O. Doebelin. 5th ed.p. cm. (McGraw-Hill series in mechanical and industrial engineering)</p><p>Includes index.ISBN 007243886X1. Measuring instruments. 2. Physical measurements. I. Title. II. Series.QC100.5.D63 2004681.2dc21 2003044176</p><p>CIPwww.mhhe.com</p><p>doe3886X_fm.qxd 4/14/2003 10:17 AM Page iv</p></li><li><p>ABOUT THE AUTHOR</p><p>Ernest O. Doebelin has received his B.S., M.S., and Ph.D. degrees in MechanicalEngineering from Case Institute of Technology and Ohio State University, respec-tively. While working on his Ph.D. at Ohio State University, he started teaching asa full-time instructor, continuing this activity for four years. Upon completion of hisPh.D., he continued teaching as Assistant Professor. At this time (1958), requiredcourses in control were essentially unheard of in mechanical engineering, but thedepartment chair encouraged Dr. Doebelin to pursue this development. Over theyears, he initiated, taught, and wrote texts for eight courses in system dynamics,measurement, and control, ranging from sophomore level to Ph.D. level courses. Ofthese courses, seven had laboratories, which Dr. Doebelin designed, supervised theconstruction of, and taught. Throughout his career, he continued to actually teach inall the laboratories in addition to training graduate-student assistants. In an era whenone could opt for an emphasis on teaching, rather than contract research, and witha love of writing, he published 11 textbooks: Dynamic Analysis and FeedbackControl (1962); Measurement Systems (1966); System Dynamics: Modeling andResponse (1972); Measurement Systems, Revised Edition (1975); System Model-ing and Response: Theoretical and Experimental Approaches (1980); MeasurementSystems, 3rd edition (1983); Control System Principles and Design (1985);Measurement Systems, 4th edition (1990); Engineering Experimentation (1995);System Dynamics: Modeling Analysis, Simulation, Design (1998); and Measure-ment Systems, 5th edition (2004). Student manuals for all the laboratories, pluscondensed, user-friendly software manuals were also produced.</p><p>The use of computer technology for system analysis and design, and as em-bedded hardware/software in operating control and measurement systems, has beena feature of all his texts, beginning with the first analog computers in the 1950s andcontinuing to todays ubiquitous PC. Particularly emphasized was the use ofdynamic system simulation software as a powerful teaching/learning tool in addi-tion to its obvious number-crunching power in practical design work. This startedwith the use of IBMs CSMP, and gradually transitioned into the PC versions ofMATLAB/SIMULINK. All the texts tried to strike the best balance between theo-retical concepts and practical implementation, using myriad examples to familiarizereaders with the building blocks of actual systems, vitally important in an erawhen many engineering students are computer savvy but often unaware of theavailable control and measurement hardware.</p><p>In a career which emphasized teaching, Dr. Doebelin was fortunate to winmany awards. These included several departmental, college, and alumni recogni-tions, and the university-wide distinguished teaching award (five selectees yearlyfrom the entire university faculty). The ASEE also presented him with the Excel-lence in Laboratory Instruction Award. After his retirement in 1990, he continued to</p><p>doe3886X_fm.qxd 4/14/2003 10:17 AM Page v</p></li><li><p>vi About the Author</p><p>maintain a full-time teaching schedule of lectures and laboratories, but only for onequarter each year. He also worked on a volunteer basis at Otterbein College, a localliberal arts school, developing and teaching a course on Understanding Technology.This was an effort to address the nationwide problem of technology illiteracy withinthe general population. As a further hobby of retirement, he has become a politics/economics junkie, focusing particularly on alternative views of globalization.</p><p>doe3886X_fm.qxd 4/14/2003 10:17 AM Page vi</p></li><li><p>CONTENTS</p><p>Preface xiv</p><p>About the Author v</p><p>P A R T 1General Concepts 1Chapter 1Types of Applications ofMeasurement Instrumentation 31.1 Why Study Measurement Systems? 31.2 Classification of Types of Measurement</p><p>Applications 51.3 Computer-Aided Machines </p><p>and Processes 71.4 Conclusion 9</p><p>Problems 10Bibliography 11</p><p>Chapter 2Generalized Configurations and FunctionalDescriptions of Measuring Instruments 132.1 Functional Elements of </p><p>an Instrument 132.2 Active and Passive Transducers 182.3 Analog and Digital Modes </p><p>of Operation 192.4 Null and Deflection Methods 212.5 Input-Output Configuration of Instruments</p><p>and Measurement Systems 22Methods of Correction for Interferingand Modifying Inputs 26</p><p>2.6 Conclusion 38Problems 39</p><p>Chapter 3Generalized Performance Characteristicsof Instruments 403.1 Introduction 403.2 Static Characteristics and</p><p>Static Calibration 41Meaning of Static Calibration 41Measured Value versus True Value 43Some Basic Statistics 45Least-Squares Calibration Curves 54Calibration Accuracy versusInstalled Accuracy 61Combination of Component Errors inOverall System-Accuracy Calculations 67Theory Validation by Experimental Testing 72Effect of Measurement Error on Quality-Control Decisions in Manufacturing 74Static Sensitivity 76Computer-Aided Calibration andMeasurement: Multiple Regression 78Linearity 85Threshold, Noise Floor, Resolution,Hysteresis, and Dead Space 86Scale Readability 91Span 91Generalized Static Stiffness andInput Impedance: Loading Effects 91Concluding Remarks on Static Characteristics 103</p><p>3.3 Dynamic Characteristics 103Generalized Mathematical Model ofMeasurement System 103Digital Simulation Methods forDynamic Response Analysis 106Operational Transfer Function 106Sinusoidal Transfer Function 107</p><p>vii</p><p>doe3886X_fm.qxd 4/14/2003 10:17 AM Page vii</p></li><li><p>viii Contents</p><p>Zero-Order Instrument 109First-Order Instrument 111Step Response of First-Order Instruments 114Ramp Response of First-Order Instruments 121Frequency Response of First-Order Instruments 123Impulse Response of First-Order Instruments 128Second-Order Instrument 131Step Response of Second-Order Instruments 133Terminated-Ramp Response of Second-Order Instruments 135Ramp Response of Second-Order Instruments 137Frequency Response ofSecond-Order Instruments 137Impulse Response of Second-Order Instruments 139Dead-Time Elements 141Logarithmic Plotting of Frequency-Response Curves 143Response of a General Form of Instrument to a Periodic Input 149Response of a General Form of Instrument to a Transient Input 157Frequency Spectra of Amplitude-Modulated Signals 167Characteristics of Random Signals 178Requirements on Instrument Transfer Functionto Ensure Accurate Measurement 194Sensor Selection Using Computer Simulation 200Numerical Correction of Dynamic Data 202Experimental Determination ofMeasurement-System Parameters 206Loading Effects under Dynamic Conditions 211Problems 214Bibliography 221</p><p>P A R T 2Measuring Devices 223Chapter 4Motion and Dimensional Measurement 2254.1 Introduction 2254.2 Fundamental Standards 2254.3 Relative Displacement: </p><p>Translational and Rotational 228Calibration 228Resistive Potentiometers 231Resistance Strain Gage 240Differential Transformers 252Synchros and Resolvers 262Variable-Inductance and Variable-Reluctance Pickups 267Eddy-Current Noncontacting Transducers 271Capacitance Pickups 273Piezoelectric Transducers 284Electro-Optical Devices 292Photographic and Electronic-ImagingTechniques 312Photoelastic, Brittle-Coating, and MoirFringe Stress-Analysis Techniques 319Displacement-to-Pressure (Nozzle-Flapper) Transducer 321Digital Displacement Transducers(Translational and Rotary Encoders) 327Ultrasonic Transducers 335</p><p>4.4 Relative Velocity: Translationaland Rotational 337Calibration 337Velocity by Electrical Differentiation ofDisplacement Voltage Signals 339Average Velocity from Measured x and t 339Mechanical Flyball Angular-Velocity Sensor 342Mechanical Revolution Counters and Timers 342</p><p>doe3886X_fm.qxd 4/14/2003 10:17 AM Page viii</p></li><li><p>Contents ix</p><p>Tachometer Encoder Methods 343Laser-Based Methods 344Radar (Microwave) Speed Sensors 345Stroboscopic Methods 346Translational-Velocity Transducers (Moving-Coil and Moving-Magnet Pickups) 347DC Tachometer Generators for Rotary-Velocity Measurement 348AC Tachometer Generators for Rotary-Velocity Measurement 349Eddy-Current Drag-Cup Tachometer 349</p><p>4.5 Relative-Acceleration Measurements 351</p><p>4.6 Seismic- (Absolute-)Displacement Pickups 351</p><p>4.7 Seismic- (Absolute-) Velocity Pickups 356</p><p>4.8 Seismic- (Absolute-) AccelerationPickups (Accelerometers) 357Deflection-Type Accelerometers 358Null-Balance- (Servo-) Type Accelerometers 369Accelerometers for Inertial Navigation 372Mechanical Loading of Accelerometerson the Test Object 373Laser Doppler Vibrometers 373</p><p>4.9 Calibration of Vibration Pickups 3754.10 Jerk Pickups 3784.11 Pendulous (Gravity-Referenced)</p><p>Angular-Displacement Sensors 3794.12 Gyroscopic (Absolute) Angular-</p><p>Displacement and Velocity Sensors 3834.13 Coordinate-Measuring Machines 3984.14 Surface-Finish Measurement 4064.15 Machine Vision 4134.16 The Global-Positioning </p><p>System (GPS) 421Problems 423Bibliography 431</p><p>Chapter 5Force, Torque, and Shaft PowerMeasurement 4325.1 Standards and Calibration 4325.2 Basic Methods of </p><p>Force Measurement 4345.3 Characteristics of </p><p>Elastic Force Transducers 441Bonded-Strain-Gage Transducers 446Differential-Transformer Transducers 452Piezoelectric Transducers 452Variable-Reluctance/FM-OscillatorDigital Systems 455Loading Effects 456</p><p>5.4 Resolution of Vector Forces and Momentsinto Rectangular Components 457</p><p>5.5 Torque Measurement on Rotating Shafts 464</p><p>5.6 Shaft Power Measurement(Dynamometers) 470</p><p>5.7 Gyroscopic Force andTorque Measurement 474</p><p>5.8 Vibrating-Wire Force Transducers 474Problems 476Bibliography 480</p><p>Chapter 6Pressure and Sound Measurement 4816.1 Standards and Calibration 4816.2 Basic Methods of </p><p>Pressure Measurement 4826.3 Deadweight Gages and Manometers 482</p><p>Manometer Dynamics 4906.4 Elastic Transducers 5006.5 Vibrating-Cylinder and Other</p><p>Resonant Transducers 5156.6 Dynamic Effects of Volumes and</p><p>Connecting Tubing 517Liquid Systems Heavily Damped, andSlow-Acting 518</p><p>doe3886X_fm.qxd 4/14/2003 10:17 AM Page ix</p></li><li><p>x Contents</p><p>Liquid Systems Moderately Damped, andFast-Acting 520Gas Systems with Tube Volume a SmallFraction of Chamber Volume 524Gas Systems with Tube Volume Comparableto Chamber Volume 526The Infinite Line-Pressure Probe 527Conclusion 528</p><p>6.7 Dynamic Testing of Pressure-MeasuringSystems 528</p><p>6.8 High-Pressure Measurement 5356.9 Low-Pressure (Vacuum) </p><p>Measurement 536Diaphragm Gages 536McLeod Gage 538Knudsen Gage 540Momentum-Transfer (Viscosity) Gages 541Thermal-Conductivity Gages 541Ionization Gages 545Dual-Gage Technique 547</p><p>6.10 Sound Measurement 547Sound-Level Meter 548Microphones 551Pressure Response of a Capacitor Microphone 554Acoustic Intensity 565Acoustic Emission 568</p><p>6.11 Pressure-Signal Multiplexing Systems 569</p><p>6.12 Special Topics 571Pressure Distribution 571Overpressure Protection forGages and Transducers 573Problems 574Bibliography 576</p><p>Chapter 7Flow Measurement 5787.1 Local Flow Velocity, Magnitude</p><p>and Direction 578Flow Visualization 578</p><p>Velocity Magnitude from Pitot-Static Tube 582Velocity Direction from...</p></li></ul>