Instrumentation and Process Control TOC

Thomas A. Weedon Philip Kirk Franklyn W. Kirk

Instrumentation and Process Control contains procedures commonly practiced in industry and the trade. Specific procedures vary with each task and must be performed by a qualified person. For maximum safety, always refer to specific manufacturer recommendations, insurance regulations, specific job site and plant procedures, applicable federal, state, and local regulations, and any authority having jurisdiction. The material contained herein is intended to be an educational resource for the user. American Technical Publishers assumes no responsibility or liability in connection with this material or its use by any individual or organization.

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© 2019 by American Technical Publishers All rights reserved 7 8 9 – 19 – 9 8 7 6 5 4 3 2 Printed in the United States of America ISBN 978-0-8269-3446-8

This book is printed on recycled paper.

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The authors and publisher are grateful for the technical information and assistance provided by the following individual: Robert E. Sherman ISA Life Fellow Shorewood, IL

Technical information and assistance was provided by the following companies and organizations.

Allen-Bradley American Society of Heating, Refrigeration and Air-Conditioning Engineers, Inc. (ASHRAE) ASI Robicon ASCO Valve, Inc. Badger Meter, Inc. Baldor Motors and Drives Banner Engineering Corp.

Bell & Gossett BERK-TEK Brooks Instrument Cleaver-Brooks Dwyer Instruments, Inc. Endress + Hauser Fireye, Inc. Fisher Controls International, LLC Fluid Components International (FCI) Fluke Corporation The Foxboro Company GE Panametrics Gerald Liu, P. Eng GE Thermometrics Hach Hart Scientific Hedland Honeywell, Inc. Honeywell’s MicroSwitch Division

Honeywell Sensing & Control Industrial Scientific Corporation Intec Controls Corporation International Society of Automation (ISA) Ircon, Inc. Jackson Systems, LLC K-TEK, LLC Kay-Ray/Sensall, Inc. McDonnell & Miller NASA/JPL/Caltech National Fire Protection Agency (NFPA) NDC Infrared Engineering Norcross Corporation Oseco, Inc. Pepperl + Fuchs, Inc. Rosemount Analytical Instruments Southern Forest Products Association Sprecher + Schuh Thermo Electron Corporation Trerice, H.O., Co. TSI Incorporated Vishay BLH Watts Regulator Company Weiss Instruments, Inc. Worcester Controls Corporation Xycom, Inc. Xylem, Inc.

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INSTRUMENTATION AND PROCESS CONTROL

INTRODUCTION TO INSTRUMENTATION

Chapter 1 — Instrumentation Overview ....................................................... 3 Chapter 2 — Fundamentals of Process Control......................................... 11 Chapter 3 — Piping and Instrumentation Diagrams ................................... 23 TEMPERATURE MEASUREMENT

Chapter 4 — Temperature, Heat, and Energy ............................................ 29 Chapter 5 — Thermal Expansion Thermometers ....................................... 37 Chapter 6 — Electrical Thermometers ....................................................... 47 Chapter 7 — Infrared Radiation Thermometers ......................................... 67 Chapter 8 — Practical Temperature Measurement and Calibration ........... 78 PRESSURE MEASUREMENT

Chapter 9 — Pressure................................................................................ 95 Chapter 10 — Mechanical Pressure Instruments..................................... 104 Chapter 11 — Electrical Pressure Instruments ........................................ 114 Chapter 12 — Practical Pressure Measurement and Calibration ............. 122 LEVEL MEASUREMENT

Chapter 13 — Mechanical Level Instruments........................................... 133 Chapter 14 — Electrical Level Instruments .............................................. 147 Chapter 15 — Ultrasonic, Radar, and Laser Level Instruments ............... 157 Chapter 16 — Nuclear Level Instruments and Weigh Systems................ 163 Chapter 17 — Practical Level Measurement and Calibration ................... 169 FLOW MEASUREMENT

Chapter 18 — Fluid Flow .......................................................................... 177 Chapter 19 — Differential Pressure Flowmeters ...................................... 185 Chapter 20 — Mechanical Flowmeters .................................................... 194 Chapter 21 — Magnetic, Ultrasonic, and Mass Flowmeters .................... 205 Chapter 22 — Practical Flow Measurement ............................................. 213 ANALYZERS

Chapter 23 — Gas Analyzers ................................................................... 219 Chapter 24 — Humidity and Solids Moisture Analyzers ........................... 233 Chapter 25 — Liquid Analyzers ................................................................ 244 Chapter 26 — Electrochemical and Composition Analyzers .................... 259 POSITION MEASUREMENT

Chapter 27 — Mechanical and Proximity Switches .................................. 271 Chapter 28 — Practical Position Measurement........................................ 283

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TRANSMISSION AND COMMUNICATION

Chapter 29 — Transmission Signals ........................................................ 293 Chapter 30 — Digital Numbering Systems and Codes ............................ 301 Chapter 31 — Digital Communications .................................................... 308 Chapter 32 — Industrial Networks ........................................................... 323 Chapter 33 — Wireless Systems.............................................................. 340 Chapter 34 — Practical Transmission and Communication...................... 352 AUTOMATIC CONTROL

Chapter 35 — Automatic Control and Process Dynamics ........................ 361 Chapter 36 — Control Strategies ............................................................. 383 Chapter 37 — Controller Tuning ............................................................... 407 Chapter 38 — Digital and Electric Controllers .......................................... 421 FINAL ELEMENTS

Chapter 39 — Hydraulic Analysis ............................................................ 436 Chapter 40 — Control Valves ................................................................... 461 Chapter 41 — Selection and Sizing of Control Valves ............................. 479 Chapter 42 — Regulators and Dampers .................................................. 499 Chapter 43 — Actuators and Positioners ................................................. 509 Chapter 44 — Variable-Speed Drives and Electric Power Controllers ..... 528 SAFETY SYSTEMS

Chapter 45 — Safety Devices and Equipment ......................................... 537 Chapter 46 — Electrical Safety Standards ............................................... 562 Chapter 47 — Safety Instrumented Systems ........................................... 573 PROCESS CONTROL APPLICATIONS

Chapter 48 — General Control Techniques .............................................. 579 Chapter 49 — Temperature Control ......................................................... 605 Chapter 50 — Pressure and Level Control............................................... 615 Chapter 51 — Flow Control ...................................................................... 624 Chapter 52 — Analysis and Multivariable Control .................................... 640 REVIEW QUESTION ANSWERS

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APPENDIX

663

GLOSSARY

673

INDEX

697

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INSTRUMENTATION AND PROCESS CONTROL

Instrumentation and Process Control presents all aspects of instrumentation and builds on the quality of previous editions as an industry-leading instructional tool. This comprehensive textbook has been used for many years to teach the principles of industrial instrumentation and controllers. This edition includes two new chapters, “Hydraulic Analysis” and “Selection and Sizing of Control Valves,” which cover design conditions, analyses, and calculations for selecting the proper control valves, which is a critical component of developing reliable processes.

Detailed illustrations and photographs from leading companies in the field enhance learning. Informative tech facts and illustrative vignettes provide supplemental content throughout the textbook.

This edition of Instrumentation and Process Control is divided into two parts — Part 1: Instrumentation, and Part 2: Process Control — and offers the following features: • Technician-level approach to the field of instrumentation • Twelve topics that cover instruments, digital communications, controls, design analyses, and applications • Systems approach to integrating instruments into a complex system • Comprehensive applications for instruments and controllers in typical industrial control systems • Examples that show how to install instruments and protect them from damaging environmental conditions The textbook is organized in a logical sequence beginning with an introduction to the field of instrumentation and continuing through all the other elements of a control system. Emphasis is placed on the fundamental scientific principles that underlie the operation of the instruments and applications are thoroughly illustrated throughout the textbook.

Introduction to Instrumentation provides an overview of industrial instrumentation and the principles of instruments, instrumentation diagrams, and control.

Temperature Measurement covers the scientific principles of temperature, heat transfer, and temperature measurement. Extensive coverage is provided of the details

necessary to install temperature instruments in systems that will work in practice. The use of thermowells, break protection, bridge circuits, and calibration procedures is included.

Pressure Measurement covers the scientific fundamentals of pressure, hydrostatics, Pascal’s law, and pressure measurement. Details of instrument protection, such as chemical seals, wet legs, valve manifolds, snubbers, and siphons, are included.

Level Measurement covers the scientific rules of point and continuous level measurement, level switches, ultrasonic and radar principles, and weigh systems. Coverage of bulk solids measurement, water columns and try cocks, diaphragm seals, and compensation for elevation changes is included.

Flow Measurement covers the scientific principles of flow, Reynolds number, compressible gases, and all types of flow measurement. Additional detail is added on the location of pressure taps, differential pressure measurement, blocking valves, flow integrators and switches, and bulk solids flow.

Analyzers covers the scientific essentials used in typical industrial analysis measurements. Extensive coverage is given on liquid, gas, oxygen, humidity, moisture, viscosity, refractive index, conductivity, pH, and ORP analyzers. Sampling systems, sampling lags, and calibration are also covered.

Position Measurement covers the operation of mechanical and proximity switches as well as their application in industrial operations. Information is provided on applications including sensor installation, rotary speed sensing, continuous web handling, and safety light curtains. The switches and sensors provide position information for operational status, alarm, or interlocking systems.

Transmission and Communication covers the operation of modern wireless and industrial digital communication systems as well as provides information on electrical and pneumatic communication systems. Information is included on digital and hex numbering systems, network

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addressing and configuration, and the OSI reference model protocol. Detail on ground loops, transmitter calibration, wiring formats, and connectors is included to help the technician understand the operation of communication systems.

Automatic Control covers the operation of modern automatic control systems as well as provides coverage of electrical controllers. Additional information is provided on how process dynamics, such as load changes, gain, lag, and dead time, affect control. Extensive coverage of proportional, integral, and derivative control strategies, and controller tuning is provided. Advanced control strategies, such as artificial intelligence, fuzzy logic, and neural networks, are also discussed.

Final Elements covers design conditions and includes hydraulic analysis calculations to determine the selection and sizing of control valves. It also covers the operation of final control elements, including control valves, regulators, dampers, actuators, positioners, solenoid valves, variable-speed drives, and electric power controllers.

Extensive detail is provided on valve installation and actuator calibration.

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Safety Systems covers the detailed operation of individual safety devices such as safety and relief valves, rupture discs, burner control systems, shutoff valves, and alarm systems.

An overview of hazardous location classifications, enclosures, risk evaluation, and safety-instrumented systems is included.

Process Control Applications covers how the instruments and control systems described in the previous chapters are assembled into complex control systems. Information is included on split range valves, high and low selectors, and gap action, cascade, and ratio controllers. Examples are included to show how to control temperature using heat exchangers, pressure using control valves, level using pumpup level control, and flow using ratio controllers. In addition, a detailed example is provided of a lead-lag combustion control system with oxygen trim. A boiler drum level and feedwater flow control system is described in detail.

Review Question Answers include answers to oddnumbered questions from the Review Questions. The Appendix includes instrumentation symbols, tables, and other information used by technicians. The Glossary provides definitions of instrumentation terms introduced in the textbook.

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INSTRUMENTATION AND PROCESS CONTROL

A brief history of the development of instrumentation allows the reader to make a historical connection to today’s instruments.

The history of process control is ever changing; early concepts are briefly discussed to explain how process control became what it is today.

Topics covered in Part 1: Instrumentation are listed for easy reference.

Charts and Tables illustrate technical details.

Topics covered in Part 2: Process Control are listed for easy reference.

Photographs of instrument applications from leading industrial companies show real-world application.

Tech Facts provide informative supplemental information.

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Enlarged details of inner mechanisms provide a better understanding of mechanical operation.

Detailed drawings show the operational details of instruments commonly used in industry.

Conceptual illustrations show relationships between systems and devices.

Key Terms are listed at the end of each chapter.

Review Questions test for comprehension of chapter content.

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Real-world techniques, such as control valve selection sheets, are shown and discussed to better prepare for work in the field.

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INSTRUMENTATION AND PROCESS CONTROL

The Instrumentation and Process Control online learner resources are self-study tools that reinforce the content covered in the book.

These online resources can be accessed using either of the following methods: • Key ATPeResources.com/QuickLinks into a web browser and enter QuickLinks™ Access code .

• Use a Quick Response (QR) reader app to scan the QR Code with a mobile device.

The online learner resources include the following: • Quick Quizzes® that provide interactive questions for each chapter, with embedded links to highlighted content within the textbook and to the Illustrated Glossary • Illustrated Glossary that serves as a helpful reference to commonly used terms, with selected terms linked to textbook illustrations • Flash Cards that provide a self-study/review of common terms and their definitions as well as P&ID symbols used in industry • Review Questions that correlate to chapter objectives and serve as a comprehension check of the content covered • Media Library that consists of videos and animations that reinforce textbook content • Internet Resources that provide access to additional resources to support continued learning

Instrumentation and Process Control Workbook

The Instrumentation and Process Control Workbook includes review questions and activities that reinforce and expand upon the information presented in the textbook. Activities elicit critical-thinking skills by having learners apply knowledge gained from the textbook to real-world applications.

To obtain information on related training products, visit atplearning.com.

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The Instrumentation and Process Control online Instructor Resources provides a comprehensive teaching resource that includes a detailed Instructional Guide, editable PowerPoint® Presentations, an interactive Image Library, multiple Assessments (Test Banks), and Answer Keys in addition to access to the online learner resources that accompany the textbook.

• The Instrumentation and Process Control ATPWebBook™ allows access to the same content as the printed textbook anytime, anywhere, using any internet-connected device.

• The Instructional Guide explains how to best use the learning resources provided and includes Instructional Plans for each chapter.

• Premium PowerPoint® Presentations provide a review of key concepts and illustrations from each chapter of the textbook.

• The Image Library provides all the numbered figures in a format that can be manipulated for instructional use.

• Supplemental Resources provide data tables and additional information for instrumentation-related topics.

• Assessments include test banks of questions based on objectives and key concepts from each chapter and also provide a pretest, and a posttest. The test banks can be used with a variety of learning management systems and test development software packages.

• Answer Keys list answers to pretest, posttest, textbook, and workbook questions.

• Learner Resources are also included as part of the instructor resources for ease of use.

To obtain information on related training products, visit atplearning.com.

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INSTRUMENTATION AND PROCESS CONTROL

Thomas A. Weedon is an engineering graduate of the Case Institute of Technology and a licensed Professional Engineer in Ohio. Mr. Weedon has many years of industrial experience in instrument engineering. He developed a course in instrumentation for a training program for new engineers. The course was taught for many years. Mr. Weedon was involved in the control system design of many chemical plants around the country, including one of the first computer-controlled chemical plants in his field. He was one of the founders of Instrumentation Technology, Inc., a control systems consulting company providing services to chemical equipment makers and plants worldwide. Consulting provided him with extensive experience in all types of instrument applications including large-scale DCS and PLC installations with modern digital and wireless instruments.

He is the author of the Instrumentation chapter in the five-volume book, Handbook of Chlor-Alkali Technology.

Philip Kirk is President of the Franklyn W. Kirk Company. Mr. Kirk has many years of experience in the instrumentation industry. His instrumentation experience includes specifying and designing instrumentation system solutions for industrial and commercial users. In this capacity, Mr. Kirk has acquired a practical knowledge of process sensors, controllers, software, and industrial instrumentation.

Franklyn W. Kirk was the founder of the Franklyn W. Kirk Company, an industrial instrument distributorship. Mr. Kirk developed and taught a four-semester course in Basic Instrumentation at the Technical Institute of Fenn College (now Cleveland State University) in Cleveland. He co-authored the first edition of the text, Instrumentation. Technical schools worldwide have used this text and the subsequent editions. Mr. Kirk continued to teach at Fenn and later for the Continuing Education Department of Cleveland State University. Mr. Kirk received the Technical Educator Award from the Cleveland Technical Societies Council. This award goes to an individual who has demonstrated outstanding performance, creative abilities, technical competence, and integrity in the practice of his or her discipline.