
Instrumentation Sensors Book
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Introduction to Instrumentation, Sensors, and Process Control
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Introduction to Instrumentation, Sensors, and Process Control
William C. Dunn
a r t e c h h o u s e . c o m
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Library of Congress Cataloging-in-Publication Data
Dunn, William C.
Introduction to instrumentation, sensors, and process control/William C. Dunn. p. cm. —(Artech House Sensors library)
ISBN 1-58053-011-7 (alk. paper)
1. Process control. 2. Detectors. I. Title. II. Series.
TS156.8.D86 2005 |
|
670.42'7—dc22 |
2005050832 |
British Library Cataloguing in Publication Data
Dunn, William C.
Introduction to instrumentation, sensors, and process control. —(Artech House sensors library)
1. Engineering instruments 2. Electronic instruments 3. Process control I. Title
681.2
ISBN-10: 1-58053-011-7
Cover design by Cameron Inc.
© 2006 ARTECH HOUSE, INC.
685 Canton Street
Norwood, MA 02062
All rights reserved. Printed and bound in the United States of America. No part of this book may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording, or by any information storage and retrieval system, without permission in writing from the publisher.
All terms mentioned in this book that are known to be trademarks or service marks have been appropriately capitalized. Artech House cannot attest to the accuracy of this information. Use of a term in this book should not be regarded as affecting the validity of any trademark or service mark.
International Standard Book Number: 1-58053-011-7
10 9 8 7 6 5 4 3 2 1

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Contents
Preface |
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xv |
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Acknowledgment |
xvi |
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CHAPTER 1 |
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Introduction to Process Control |
1 |
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1.1 |
Introduction |
1 |
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1.2 |
Process Control |
1 |
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1.2.1 |
Sequential Process Control |
2 |
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1.2.2 |
Continuous Process Control |
2 |
1.3 |
Definition of the Elements in a Control Loop |
4 |
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1.4 |
Instrumentation and Sensors |
5 |
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1.4.1 |
Instrument Parameters |
5 |
1.5 |
Control System Evaluation |
9 |
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1.5.1 |
Stability |
9 |
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1.5.2 |
Regulation |
9 |
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1.5.3 |
Transient Response |
9 |
1.6 |
Analog and Digital Data |
10 |
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1.6.1 |
Analog Data |
10 |
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1.6.2 |
Digital Data |
10 |
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1.6.3 |
Pneumatic Data |
10 |
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1.6.4 |
Smart Sensors |
11 |
1.7 |
Process Facility Considerations |
11 |
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1.8 |
Summary |
12 |
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Definitions |
12 |
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References |
14 |
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CHAPTER 2 |
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Units and Standards |
15 |
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2.1 |
Introduction |
15 |
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2.1.1 |
Units and Standards |
15 |
2.2 |
Basic Units |
16 |
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2.3 |
Units Derived from Base Units |
16 |
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2.3.1 Units Common to Both the English and SI Systems |
16 |
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2.3.2 English Units Derived from Base Units |
16 |
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2.3.3 SI Units Derived from Base Units |
18 |
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2.3.4 Conversion Between English and SI Units |
18 |
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Contents |
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2.3.5 Metric Units not Normally Used in the SI System |
20 |
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2.4 |
Standard Prefixes |
21 |
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2.5 |
Standards |
22 |
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2.5.1 |
Physical Constants |
22 |
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2.5.2 |
Standards Institutions |
22 |
2.6 |
Summary |
23 |
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References |
23 |
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CHAPTER 3 |
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Basic Electrical Components |
25 |
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3.1 |
Introduction |
25 |
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3.2 |
Circuits with R, L, and C |
25 |
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3.2.1 |
Voltage Step Input |
25 |
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3.2.2 |
Time Constants |
27 |
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3.2.3 |
Sine Wave Inputs |
28 |
3.3 |
RC Filters |
32 |
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3.4 |
Bridge Circuits |
34 |
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3.4.1 |
Voltage Dividers |
34 |
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3.4.2 |
dc Bridge Circuits |
34 |
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3.4.3 |
ac Bridge Circuits |
38 |
3.5 |
Summary |
39 |
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References |
40 |
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CHAPTER 4 |
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Analog Electronics |
41 |
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4.1 |
Introduction |
41 |
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4.2 |
Analog Circuits |
41 |
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4.2.1 |
Operational Amplifier Introduction |
41 |
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4.2.2 |
Basic Op-Amp |
42 |
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4.2.3 |
Op-Amp Characteristics |
42 |
4.3 |
Types of Amplifiers |
45 |
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4.3.1 |
Voltage Amplifiers |
45 |
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4.3.2 |
Converters |
50 |
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4.3.3 |
Current Amplifiers |
52 |
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4.3.4 Integrating and Differentiating Amplifiers |
53 |
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4.3.5 |
Nonlinear Amplifiers |
54 |
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4.3.6 |
Instrument Amplifiers |
55 |
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4.3.7 |
Input Protection |
57 |
4.4 |
Amplifier Applications |
57 |
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4.5 |
Summary |
58 |
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References |
58 |
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CHAPTER 5 |
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Digital Electronics |
59 |
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5.1 |
Introduction |
59 |
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5.2 |
Digital Building Blocks |
59 |
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5.3 |
Converters |
61 |
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Contents |
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vii |
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5.3.1 |
Comparators |
62 |
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5.3.2 Digital to Analog Converters |
64 |
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5.3.3 Analog to Digital Converters |
68 |
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5.3.4 |
Sample and Hold |
72 |
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5.3.5 Voltage to Frequency Converters |
72 |
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5.4 |
Data Acquisition Devices |
74 |
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5.4.1 |
Analog Multiplexers |
74 |
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5.4.2 |
Digital Multiplexers |
74 |
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5.4.3 |
Programmable Logic Arrays |
75 |
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5.4.4 |
Other Interface Devices |
75 |
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5.5 |
Basic Processor |
75 |
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5.6 |
Summary |
76 |
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References |
77 |
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CHAPTER 6 |
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Microelectromechanical Devices and Smart Sensors |
79 |
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6.1 |
Introduction |
79 |
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6.2 |
Basic Sensors |
80 |
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6.2.1 |
Temperature Sensing |
80 |
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6.2.2 |
Light Intensity |
80 |
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6.2.3 |
Strain Gauges |
81 |
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6.2.4 |
Magnetic Field Sensors |
82 |
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6.3 |
Piezoelectric Devices |
84 |
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6.3.1 |
Time Measurements |
86 |
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6.3.2 |
Piezoelectric Sensors |
87 |
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6.3.3 |
PZT Actuators |
88 |
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6.4 |
Microelectromechanical Devices |
88 |
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6.4.1 |
Bulk Micromachining |
89 |
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6.4.2 |
Surface Micromachining |
91 |
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6.5 |
Smart Sensors Introduction |
94 |
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6.5.1 |
Distributed System |
95 |
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6.5.2 |
Smart Sensors |
96 |
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6.6 |
Summary |
96 |
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References |
97 |
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CHAPTER 7 |
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Pressure |
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99 |
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7.1 |
Introduction |
99 |
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7.2 |
Pressure Measurement |
99 |
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7.2.1 |
Hydrostatic Pressure |
99 |
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7.2.2 |
Specific Gravity |
100 |
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7.2.3 |
Units of Measurement |
101 |
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7.2.4 |
Buoyancy |
103 |
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7.3 |
Measuring Instruments |
105 |
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7.3.1 |
Manometers |
105 |
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7.3.2 Diaphragms, Capsules, and Bellows |
106 |
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7.3.3 |
Bourdon Tubes |
108 |
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viii |
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Contents |
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7.3.4 |
Other Pressure Sensors |
109 |
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7.3.5 |
Vacuum Instruments |
110 |
7.4 |
Application Considerations |
111 |
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7.4.1 |
Selection |
111 |
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7.4.2 |
Installation |
112 |
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7.4.3 |
Calibration |
112 |
7.5 |
Summary |
113 |
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Definitions |
113 |
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References |
114 |
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CHAPTER 8 |
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Level |
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115 |
8.1 |
Introduction |
115 |
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8.2 |
Level Measurement |
115 |
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8.2.1 |
Direct Level Sensing |
115 |
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8.2.2 |
Indirect Level Sensing |
118 |
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8.2.3 |
Single Point Sensing |
124 |
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8.2.4 Level Sensing of Free-Flowing Solids |
125 |
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8.3 |
Application Considerations |
126 |
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8.4 |
Summary |
128 |
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References |
128 |
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CHAPTER 9 |
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Flow |
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129 |
9.1 |
Introduction |
129 |
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9.2 |
Fluid Flow |
129 |
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9.2.1 |
Flow Patterns |
129 |
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9.2.2 |
Continuity Equation |
131 |
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9.2.3 |
Bernoulli Equation |
132 |
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9.2.4 |
Flow Losses |
134 |
9.3 |
Flow Measuring Instruments |
136 |
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9.3.1 |
Flow Rate |
136 |
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9.3.2 |
Total Flow |
142 |
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9.3.3 |
Mass Flow |
144 |
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9.3.4 Dry Particulate Flow Rate |
144 |
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9.3.5 |
Open Channel Flow |
145 |
9.4 |
Application Considerations |
145 |
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9.4.1 |
Selection |
145 |
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9.4.2 |
Installation |
147 |
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9.4.3 |
Calibration |
147 |
9.5 |
Summary |
147 |
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Definitions |
148 |
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References |
148 |
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Contents |
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ix |
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CHAPTER 10 |
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Temperature and Heat |
149 |
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10.1 |
Introduction |
149 |
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10.2 |
Temperature and Heat |
149 |
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10.2.1 |
Temperature Units |
149 |
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10.2.2 |
Heat Energy |
151 |
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10.2.3 |
Heat Transfer |
153 |
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10.2.4 |
Thermal Expansion |
155 |
10.3 |
Temperature Measuring Devices |
157 |
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10.3.1 |
Expansion Thermometers |
157 |
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10.3.2 |
Resistance Temperature Devices |
160 |
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10.3.3 |
Thermistors |
161 |
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10.3.4 |
Thermocouples |
162 |
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10.3.5 |
Pyrometers |
164 |
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10.3.6 |
Semiconductor Devices |
165 |
10.4 |
Application Considerations |
166 |
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10.4.1 |
Selection |
166 |
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10.4.2 |
Range and Accuracy |
166 |
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10.4.3 |
Thermal Time Constant |
167 |
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10.4.4 |
Installation |
168 |
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10.4.5 |
Calibration |
168 |
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10.4.6 |
Protection |
168 |
10.5 |
Summary |
169 |
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Definitions |
169 |
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References |
170 |
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CHAPTER 11 |
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Position, Force, and Light |
171 |
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11.1 |
Introduction |
171 |
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11.2 |
Position and Motion Sensing |
171 |
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11.2.1 Position and Motion Measuring Devices |
171 |
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11.2.2 |
Position Application Considerations |
176 |
11.3 |
Force, Torque, and Load Cells |
177 |
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11.3.1 Force and Torque Introduction |
178 |
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11.3.2 |
Stress and Strain |
178 |
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11.3.3 Force and Torque Measuring Devices |
181 |
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11.3.4 |
Strain Gauge Sensors |
183 |
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11.3.5 Force and Torque Application Considerations |
186 |
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11.4 |
Light |
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186 |
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11.4.1 |
Light Introduction |
186 |
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11.4.2 |
EM Radiation |
186 |
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11.4.3 |
Light Measuring Devices |
188 |
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11.4.4 |
Light Sources |
188 |
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11.4.5 |
Light Application Considerations |
189 |
11.5 |
Summary |
190 |
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Definitions |
190 |
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References |
191 |
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Contents |
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CHAPTER 12 |
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Humidity and Other Sensors |
193 |
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12.1 |
Humidity |
193 |
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12.1.1 |
Humidity Introduction |
193 |
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12.1.2 |
Humidity Measuring Devices |
194 |
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12.1.3 |
Humidity Application Considerations |
197 |
12.2 |
Density and Specific Gravity |
198 |
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12.2.1 |
Density and Specific Gravity Introduction |
198 |
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12.2.2 |
Density Measuring Devices |
199 |
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12.2.3 |
Density Application Considerations |
202 |
12.3 |
Viscosity |
202 |
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12.3.1 |
Viscosity Introduction |
202 |
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12.3.2 |
Viscosity Measuring Instruments |
203 |
12.4 |
Sound |
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204 |
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12.4.1 |
Sound Measurements |
204 |
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12.4.2 |
Sound Measuring Devices |
205 |
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12.4.3 |
Sound Application Considerations |
206 |
12.5 |
pH Measurements |
206 |
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12.5.1 |
pH Introduction |
206 |
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12.5.2 |
pH Measuring Devices |
207 |
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12.5.3 |
pH Application Considerations |
207 |
12.6 |
Smoke and Chemical Sensors |
208 |
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12.6.1 |
Smoke and Chemical Measuring Devices |
208 |
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12.6.2 |
Smoke and Chemical Application Consideration |
208 |
12.7 |
Summary |
209 |
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Definitions |
209 |
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References |
210 |
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CHAPTER 13 |
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Regulators, Valves, and Motors |
211 |
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13.1 |
Introduction |
211 |
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13.2 |
Pressure Controllers |
211 |
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13.2.1 |
Pressure Regulators |
211 |
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13.2.2 |
Safety Valves |
213 |
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13.2.3 |
Level Regulators |
214 |
13.3 |
Flow Control Valves |
215 |
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13.3.1 |
Globe Valve |
215 |
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13.3.2 |
Butterfly Valve |
217 |
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13.3.3 |
Other Valve Types |
218 |
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13.3.4 |
Valve Characteristics |
219 |
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13.3.5 |
Valve Fail Safe |
219 |
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13.3.6 |
Actuators |
220 |
13.4 |
Power Control |
221 |
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13.4.1 |
Electronic Devices |
222 |
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13.4.2 |
Magnetic Control Devices |
227 |
13.5 |
Motors |
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227 |
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13.5.1 |
Servo Motors |
228 |