Programmable Logic Controllers m This page intentionally left blank m Programmable Logic Controllers Fifth Edition Frank D Petruzella m PROGRAMMABLE LOGIC CONTROLLERS, FIFTH EDITION Published by McGraw-Hill Education, Penn Plaza, New York, NY 10121 Copyright © 2017 by McGraw-Hill Education All rights reserved Printed in the United States of America Previous editions © 2011, 2005, 1998 No part of this publication may be reproduced or distributed in any form or by any means, or stored in a database or retrieval system, without the prior written consent of McGraw-Hill Education, including, but not limited to, in any network or other electronic storage or transmission, or broadcast for distance learning Some ancillaries, including electronic and print components, may not be available to customers outside the United States This book is printed on acid-free paper RMN/RMN ISBN 978-0-07-337384-3 MHID 0-07-337384-2 Senior Vice President, Products & Markets: Kurt L Strand Vice President, General Manager, Products & Markets: Marty Lange Vice President, Content Design & Delivery: Kimberly Meriwether David Managing Director: Thomas Timp Global Brand Manager: Raghu Srinivasan Director, Product Development: Rose Koos Product Developer: Vincent Bradshaw Marketing Manager: Nick McFadden Digital Product Developer: Amy Bumbaco, Ph.D Director, Content Design & Delivery: Linda Avenarius Executive Program Manager: Faye M Herrig Content Project Managers: Jessica Portz, Tammy Juran, Sandra Schnee Buyer: Laura M Fuller Content Licensing Specialist: Lorraine Buczek Compositor: MPS Limited Printer: R R Donnelley All credits appearing on page or at the end of the book are considered to be an extension of the copyright page Library of Congress Cataloging-in-Publication Data Petruzella, Frank D., author Programmable logic controllers / Frank D Petruzella.—Fifth edition pages cm Includes index ISBN 978-0-07-337384-3 (alk paper)—ISBN 0-07-337384-2 (alk paper) controllers I Title TJ223.P76P48 2017 629.8’95—dc23 Programmable 2015035302 The Internet addresses listed in the text were accurate at the time of publication The inclusion of a website does not indicate an endorsement by the authors or McGraw-Hill Education, and McGraw-Hill Education does not guarantee the accuracy of the information presented at these sites mheducation.com/highered m Contents Preface viii Acknowledgments xi About the Author xii Chapter Programmable Logic Controllers (PLCs): An Overview 1.1 Programmable Logic Controllers 1.2 Parts of a PLC 1.3 Principles of Operation 1.4 Modifying the Operation 11 1.5 PLCs versus Computers 11 1.6 PLC Size and Application 12 Review Questions 15 Problems 16 Chapter PLC Hardware Components 2.1 2.2 2.3 2.4 2.5 17 The I/O Section Discrete I/O Modules Analog I/O Modules Special I/O Modules I/O Specifications Typical Discrete I/O Module Specifications Typical Analog I/O Module Specifications 2.6 The Central Processing Unit (CPU) 2.7 Memory Design 2.8 Memory Types 2.9 Programming Terminal Devices 2.10 Recording and Retrieving Data 2.11 Human Machine Interfaces (HMIs) Review Questions Problems 18 22 27 31 33 33 34 Chapter 46 3.1 3.2 3.3 3.4 3.5 3.6 3.7 Number Systems and Codes Decimal System Binary System Negative Numbers Octal System Hexadecimal System Binary Coded Decimal (BCD) System Gray Code 35 36 37 39 39 39 43 45 47 47 49 49 50 51 53 3.8 ASCII Code 3.9 Parity Bit 3.10 Binary Arithmetic 3.11 Floating Point Arithmetic Review Questions Problems 54 54 55 57 59 60 Chapter 61 Fundamentals of Logic 4.1 4.2 The Binary Concept 62 AND, OR, and NOT Functions 62 The AND Function 62 The OR Function 63 The NOT Function 64 The Exclusive-OR (XOR) Function 65 4.3 Boolean Algebra 65 4.4 Developing Logic Gate Circuits from Boolean Expressions 66 4.5 Producing the Boolean Equation for a Given Logic Gate Circuit 66 4.6 Hardwired Logic versus Programmed Logic 67 4.7 Programming Word Level Logic Instructions 70 Review Questions 72 Problems 72 Chapter Basics of PLC Programming 74 5.1 Processor Memory Organization 75 Program Files 75 Data Files 75 5.2 Program Scan 78 5.3 PLC Programming Languages 81 5.4 Bit-Level Logic Instructions 83 5.5 Instruction Addressing 86 5.6 Branch Instructions 87 5.7 Internal Relay Instructions 89 5.8 Programming Examine If Closed and Examine If Open Instructions 90 5.9 Entering the Ladder Diagram 91 5.10 Modes of Operation 93 5.11 Connecting with Analog Devices 93 Review Questions 95 Problems 96 v m Chapter Developing Fundamental PLC Wiring Diagrams and Ladder Logic Programs Chapter 98 6.1 6.2 6.3 6.4 6.5 6.6 Electromagnetic Control Relays 99 Contactors 100 Motor Starters 101 Manually Operated Switches 102 Mechanically Operated Switches 103 Sensors 104 Proximity Sensor 104 Magnetic Reed Switch 107 Light Sensors 107 Ultrasonic Sensors 109 Strain/Weight Sensors 110 Temperature Sensors 110 Flow Measurement 111 Velocity and Position Sensors 111 6.7 Output Control Devices 112 6.8 Seal-In Circuits 114 6.9 Electrical Interlocking Circuits 115 6.10 Latching Relays 116 6.11 Converting Relay Schematics into PLC Ladder Programs 121 6.12 Writing a Ladder Logic Program Directly from a Narrative Description 124 6.13 Instrumentation 127 Review Questions 128 Problems 129 Chapter Programming Timers 7.1 Mechanical Timing Relays 7.2 Timer Instructions 7.3 On-Delay Timer Instruction 7.4 Off-Delay Timer Instruction 7.5 Retentive Timer 7.6 Cascading Timers Review Questions Problems Chapter Programming Counters 8.1 8.2 Counter Instructions Up-Counter One-Shot Instruction 8.3 Down-Counter 8.4 Cascading Counters 8.5 Incremental Encoder-Counter Applications 8.6 Combining Counter and Timer Functions 8.7 High-Speed Counters Review Questions Problems vi 131 132 134 135 140 144 147 151 151 156 157 159 162 166 170 173 174 177 179 179 Program Control Instructions 9.1 9.2 9.3 9.4 9.5 Program Control Master Control Reset Instruction Jump Instruction Subroutine Functions Immediate Input and Immediate Output Instructions 9.6 Forcing External I/O Addresses 9.7 Safety Circuitry 9.8 Selectable Timed Interrupt 9.9 Fault Routine 9.10 Temporary End Instruction 9.11 Suspend Instruction Review Questions Problems Chapter 10 Data Manipulation Instructions 10.1 Data Manipulation 10.2 Data Transfer Operations 10.3 Data Compare Instructions 10.4 Data Manipulation Programs 10.5 Numerical Data I/O Interfaces 10.6 Closed-Loop Control Review Questions Problems Chapter 11 Math Instructions 11.1 Math Instructions 11.2 Addition Instruction 11.3 Subtraction Instruction 11.4 Multiplication Instruction 11.5 Division Instruction 11.6 Other Word-Level Math Instructions 11.7 File Arithmetic Operations Review Questions Problems Chapter 12 Sequencer and Shift Register Instructions 12.1 Mechanical Sequencers 12.2 Sequencer Instructions 12.3 Sequencer Programs 12.4 Bit Shift Registers 12.5 Word Shift Operations Review Questions Problems 184 185 185 188 190 193 195 197 200 201 201 202 203 203 207 208 208 216 221 224 226 230 231 234 235 236 238 239 240 242 245 247 248 252 253 255 259 264 272 277 277 Contents m Chapter 13 PLC Installation Practices, Editing, and Troubleshooting 13.1 13.2 13.3 13.4 13.5 13.6 13.7 13.8 13.9 PLC Enclosures Electrical Noise Leaky Inputs and Outputs Grounding Voltage Variations and Surges Program Editing and Commissioning Programming and Monitoring Preventive Maintenance Troubleshooting Processor Module Input Malfunctions Output Malfunctions Ladder Logic Program 13.10 PLC Programming Software Review Questions Problems Chapter 14 Process Control, Network Systems, and SCADA 14.1 14.2 14.3 14.4 14.5 14.6 Types of Processes Structure of Control Systems On/Off Control PID Control Motion Control Data Communications Data Highway Serial Communication DeviceNet ControlNet EtherNet/IP Modbus Fieldbus PROFIBUS-DP 14.7 Supervisory Control and Data Acquisition (SCADA) Review Questions Problems Chapter 15 ControlLogix Controllers Part Memory and Project Organization Memory Layout Configuration Project Tasks Programs 281 282 284 285 285 287 288 289 291 292 292 292 294 294 299 302 302 Part Part 305 306 308 310 311 315 316 322 322 322 325 325 326 326 326 Part Part 328 331 332 333 334 334 334 335 336 336 Part Routines Tags Structures Creating Tags Monitoring and Editing Tags Array Review Questions Bit-Level Programming Program Scan Creating Ladder Logic Tag-Based Addressing Adding Ladder Logic to the Main Routine Internal Relay Instructions Latch and Unlatch Instructions One-Shot Instruction Review Questions Problems Programming Timers Timer Predefined Structure On-Delay Timer (TON) Off-Delay Timer (TOF) Retentive Timer On (RTO) Cascading of Timers Review Questions Problems Programming Counters Counters Count-Up (CTU) Counter Count-Down (CTD) Counter Combining Counter and Timer Functions Review Questions Problems Math, Comparison, and Move Instructions Math Instructions Comparison Instructions Move Instructions Combining Math, Comparison, and Move Instructions Review Questions Problems Function Block Programming Function Block Diagram (FBD) FBD Programming Review Questions Problems 337 337 340 341 342 342 344 345 345 346 347 348 350 352 353 356 356 358 358 359 362 364 365 367 367 368 368 369 371 372 373 373 374 374 376 379 380 383 383 384 384 388 394 394 Glossary 395 Index 407 Contents vii m Preface Programmable logic controllers (PLCs) continue to evolve as new technologies are added to their capabilities As PLC technology has advanced, so have programming languages and communications capabilities Today’s PLCs offer faster scan times, space efficient high-density input/ output systems, and special interfaces to allow nontraditional devices to be attached directly to the PLC Now in its Fifth Edition, changes made to the content of the text have been made solely based on reviews from current instructors and include: • material that should be added or deleted from chapters • topics requiring more in-depth coverage • increased integration of the ControlLogix platform of controllers • chapter modifications require to meet current curriculum needs The primary source of information for a particular PLC is always the accompanying user manuals provided by the manufacturer This textbook is not intended to replace the vendor’s reference material, but rather to complement, clarify, and expand on this information The text covers the basics of programmable logic controllers in a manner that complements instruction with a SLC-500 or ControlLogix platform The underlying PLC principles and concepts covered in the text are common to most manufacturers They serve to maximize the knowledge gained through on-the-job training and programs offered by different vendors The text is written in an easy-to-read style that is designed for students with no prior PLC experience For example, when the operation of a program is called for, a bulleted list is used to summarize its execution The bulled list replaces a lengthy paragraph and is especially helpful when covering the different steps related to the execution of a program Each chapter begins with a brief introduction outlining chapter coverage and learning objectives When applicable, the relay equivalent of the virtual programmed instruction is explained first, followed by the appropriate PLC instruction Chapters conclude with a set of review questions and problems The review questions are closely related to the chapter objectives and require students to recall and apply information covered in the chapter The problems range from easy to difficult, thus challenging students at various levels of competence Features new to the Fifth Edition include: • Key concepts and terms are highlighted in bold the first time they appear • New/updated photos and line art for every chapter • New topics for every chapter as requested by reviewers • Addition review questions for new topics • Updated instructor PowerPoint lessons • More than 175 SLC-500 and ControlLogix program simulation videos tied directly to the programs studied in the text In addition, students who are using McGrawHill’s Connect can watch simulated, step-by-step execution of numerous ladder logic programming examples They’re guided by an audio commentary that explains what to look for as the program is executed The videos are part of the Student Resources section of Connect viii m Chapter changes in this edition include: Chapter • • • • • Testing of field devices Extended coverage of scan cycle sequence Additional test bank questions Program video simulations New and modified line diagrams and photos Chapter • ControlLogix Base and Alias addressing • Extended coverage of DC module Sinking and Sourcing • Analog module input sensor 2-, 3-, and 4-wire connections • Scaling of PLC analog inputs and outputs • Extended coverage of Human Machine Interfaces (HMIs) • Additional chapter review questions • Additional test bank questions • Program video simulations • New and modified line diagrams and photos Chapter • • • • • • 16 bit 2’s complement Floating point arithmetic Additional chapter problems Additional test bank questions Program video simulations New and modified line diagrams and photos Chapter • • • • • Modification to hardwired programming examples Additional test bank questions Additional chapter review questions Program video simulations New and modified line diagrams and photos Chapter • • • • Electrical versus logical continuity Evaluating XIO and XIC bit instructions Rack-based versus tag-based addressing Connecting with analog devices • • • • Additional test bank questions Additional chapter review questions Program video simulations New and modified line diagrams and photos Chapter • • • • • • • • Magnetic reed float switch Resistance temperature detectors (RTDs) Electrical interlocking circuits Process instrumentation Additional test bank questions Additional chapter review questions Program video simulations New and modified line diagrams and photos Chapter • • • • • • • • Extended coverage of timer instructions ControlLogix timer instruction Reciprocating timers TON timer bit table TOF timer bit table Additional test bank questions Program video simulations New and modified line diagrams and photos Chapter • • • • • • • ControlLogix counter instruction Extended coverage of CTD instruction Additional information on incremental encoders New section on High-Speed Counter instruction Additional test bank questions Program video simulations New and modified line diagrams and photos Chapter • Extended coverage of MCR instruction • Extended coverage of Jump instruction • Extended coverage of Immediate Input and Output instructions • ControlLogix Immediate Output instruction • Additional test bank questions • Program video simulations • New and modified line diagrams and photos Preface ix m Chapter 10 • • • • Extended coverage of the Masked Move instruction New example of a copy instruction program New example of a data compare program ControlLogix Limit Comparison instruction and program • Additional test bank questions • Program video simulations • New and modified line diagrams and photos Chapter 11 • • • • • • • • Extended coverage of basic math instruction New example of a compute instruction program New coverage Modulo (MOD) instruction New scale analog input using the SCP instruction New scale analog output using the SCP instruction Additional test bank questions Program video simulations New and modified line diagrams and photos Chapter 12 • Extended coverage of Sequencer Output (SQO) instruction • ControlLogix Sequencer Output (SQO) instruction and program • ControlLogix shift registers instruction and program • ControlLogix FIFO instruction and program • Additional test bank questions • Program video simulations • New and modified line diagrams and photos Chapter 13 • Extended coverage of communications using RSLinx and RSWho • Additional test bank questions • Program video simulations • New and modified line diagrams and photos Chapter 14 • SERCOS standard communication for motion control • HART communication protocol x • • • • • SCADA alarm monitoring FactoryTalk services platform Additional test bank questions Program video simulations New and modified line diagrams and photos Chapter 15 Part • Extended coverage of tag types • Program video simulations • New and modified line diagrams and photos Part • Reversing conveyor motor program and operation • Motor pilot light internal relay program and operation • Latch/unlatch car wash program and operation • One-shot program instructions used in conjunction with math operations • Program video simulations • New and modified line diagrams and photos Part • Cascading TON timers for timed event-driven routines program and operation • Program video simulations • New and modified line diagrams and photos Part • Combining Counter and Timer Functions program and operation • Program video simulations • New and modified line diagrams and photos Part • Monitoring the setting of a thumbwheel switch program and operation • PLC program for three-speed control of a conveyor system program and operation • Conveyor parts tracking program and operation • Program video simulations • New and modified line diagrams and photos • Part Function block parameters tab • Program video simulations • New and modified line diagrams and photos Preface m Acknowledgments I would like to thank the following reviewers for their comments and suggestions: Randy Owens Henderson Community College Noureddine Bekhouche Jacksonville State University James Schabowski Waukesha County Technical College Mark Bohnet Northwest Iowa Community College Jenifer Shannon Penn State University, Berks Campus Michael Buck Dakota County Technical College Accounties Lashan Smith Tri-County Technical College Wayne Buroker Waukesha County Technical College Kenneth E Swayne Pellissippi State Community College Jerry Clark Northwest Mississippi Community College John Veitch SUNY Adirondack Chris Haley North Georgia Technical College William Walker Truckee Meadows Community College Garrett Hunter Western Illinois University Robert Permenter Albany Technical College Wael Ibrahim ECPI University A special thanks to Don Pelster of Nashville State Community College, for his outstanding work on performing a technical edit of the text and providing us with detailed feedback, suggestions and recommendations Ahmed Kamal Tennessee Tech University Gholam H Massiha University of Louisiana at Lafayette Frank D Petruzella xi m About the Author Frank D Petruzella has extensive practical experience in the electrical control field, as well as many years of experience teaching and authoring textbooks Before becoming a full time educator, he was employed as an apprentice and electrician in areas of electrical installation and maintenance He holds a Master of Science degree from Niagara University, a Bachelor of Science degree from the State University of New York College–Buffalo, as well as diplomas in Electrical Power and Electronics from the Erie County Technical Institute xii m P rogrammable Logic Controllers makes it easy to learn PLCs from the ground up! Upto-the-minute revisions include all the newest developments in programming, installing, and maintaining processes Clearly developed chapters deliver the organizing objectives, explanatory content with helpful diagrams and illustrations, and closing review problems that evaluate retention of the chapter objectives Ima Chapter Objectives After completing this chapter, you will be able to: • • • CHAPTER OBJECTIVES overview the chapter, letting students and instructors focus on the main points to better grasp concepts and retain information • • Describe the operation of pneumatic on-delay and off-delay timers Describe PLC timer instruction and differentiate between a nonretentive and retentive timer Convert fundamental timer relay schematic diagrams to PLC ladder logic programs Analyze and interpret typical PLC timer ladder logic programs Program the control of outputs using the timer instruction control bits Th coi de in the oth ind Chapter content includes rich illustrative detail and extensive visual aids, allowing students to grasp concepts more quickly and understand practical applications Inputs Outputs Ladder logic program L2 L1 S1 MOV MOVE Source S1 Destination Thermocouple Heater LED B3:0/1 LEQ LESS THAN OR EQUAL Source A Thermocouple Source B Thermocouple LED Here, drawings and photos of real-world input and output devices have been included (Internal) LED Display 597 59 B3:0/2 GEQ GREATER THAN OR EQUAL Source A Thermocouple Source B S1 (Internal) 603 High temp B3:0/2 Low temp B3:0/1 Heater Heater HMI Package Tag Database PLC I/O Server In Chapter 02, students not only read about but can also see how HMIs fit into an overall PLC system, giving them a practical introduction to the topics Communication ports Start Stop Graphic Screen xiii m Coverage of communications and control networks utilizes clear graphics to demonstrate how things work Input Ladder logic program L1 I:1/3 O:2/5 L2 O:2/5 Force> ON OFF DeviceNet Scanner Module Outputs O:2/5 I:1/3 I/O Module ON O:2/6 O:2/6 4-wire cable and connector Conventional system DeviceNet system M ON BULLETED LISTS break down processes to helpfully summarize execution of tasks • The processor ignores the actual state of input limit switch I:1/3 • Although limit switch I:1/3 is off (0 or false) the processor considers it as being in the on (1 or true) state • The program scan records this, and the program is executed with this forced status • In other words, the program is executed as if the limit switch were actually closed Ladder logic Timer_Sw TON Timer On Delay Timer Status_Timer 10000 Preset Accum EN DN Outputs L2 Status_Timer.EN EN_PL Status_Timer.TT TT_PL Status_Timer.DN DN_PL EN_PL L1 Input Timer_Sw TT_PL DN_PL Diagrams, such as this one illustrating an overview of the function block programming language, help students put the pieces together FBD equivalent TONR_01 TONR Timer On Delay with Reset Timer_Sw Operation of the program can be viewed in real time Motor_Stop Motor_Start Track_Motor Track_Motor Enter_LS TimerEnable Exit_LS EN TT DN Slot 00 00 01 01 02 02 03 03 0 0 ACC_Value EN_PL TT_PL DN_PL Figure 15-110 Comparison between ladder logic and the FBD equivalent for a 10 second TON and TONR timer Wash_In_Use • When the Motor_Stop button is opened the output of the BAND block turns false to de-energize the contactor coil and stop the motor Wash_In_Use U Discrete I/O ACC PRE Do_Not_Enter_Sign Wash_In_Use xiv 10000 Reset L Slot 10000 Figure 15-110 shows a comparison between ladder logic and the FBD equivalent for the 10 second TON (ondelay timer) and TONR (on-delay with reset) The operation of the FBD can be summarized as follows: • Opening the Timer_Sw resets all outputs as well as the accumulated value to zero • The timer can also be reset by way of the Reset input Figure 15-111 shows a comparison between ladder logic and the FBD equivalent for the Up/Down counter used to limit the number of parts stored in a buffer zone to 50 The operation of the FBD can be summarized as follows: ControlLogix More than 175 SLC-500 and • When the Timer_Sw is closed, the TONR function block timer turns true and starts accumulating program simulation videos tied time the programs studied in the text • The accumulated time is monitored by the output reference tag named ACC • The EN (enable bit) output changes to 1 to turn on the EN_PL • The TT (timer timing bit) output changes to 1 to turn on the TT_PL • The timer times out after 10 seconds to set the DN (done bit) to 1 and turn on the DN_PL and reset the TT bit to zero and turn off the TT_PL • The EN bit and EN_PL remain on as long as the Timer_Sw stays toggled closed • The CTUD up/down counter function block accudirectly to • • • • mulated value is initially reset by momentary actuation of the Restart_Button The accumulated count is monitored by the output reference tag named ACC Each time a part enters the buffer zone, the Enter_ Limit_Sw is actuated and the CUEnable input turns true to increment the count by 1 Each time a part exits the buffer zone, the Exit_ Limit_Sw is actuated and the CDEnable input turns true to decrement the count by 1 Whenever the number of parts in the buffer zone reaches 50 the DN bit is set to 1 and the output of m END-OF-CHAPTER REVIEWS are structured to reinforce chapter objectives CHAPTER REVIEW QUESTIONS Explain the basic operating principle of an electro15 Compare the operation of the reflective-type and magnetic control relay through-beam photoelectric sensors What is the operating difference between a nor16 Give an explanation of how a scanner and a decoder mally open and a normally closed relay contact? act in conjunction with each other to read a bar code In what ways are control relay coils and contacts rated? 17 How does an ultrasonic sensor operate? How contactors differ from relays? 18 Explain the principle of operation of a strain gauge What is the main difference between a contactor 19 Explain the principle of operation of a thermocouple and a magnetic motor starter? 20 What is the most common approach taken with re6 a Draw the schematic for an across-the-line AC gard to the measurement of fluid flow? magnetic motor starter 21 Explain how a tachometer is used to measure rotab With reference to this schematic, explain the tional speed function of each of the following parts: 22 How does an optical encoder work? i Main contact M 23 Draw an electrical symbol used to represent each of ii Control contact M the following PLC control devices: iii Starter coil M a Pilot light f Heater iv OL relay coils b Relay g Solenoid v OL relay contact c Motor starter coil h Solenoid valve The current requirement for the control circuit of a d OL relay contact i Motor magnetic starter is normally much smaller than that e Alarm j Horn required by the power circuit Why? 24 Explain the function of each of the following Compare the method of operation of each of the actuators: following types of switches: a Solenoid a Manually operated switch b Solenoid valve b Mechanically operated switch c Stepper motor c Proximity switch 25 Compare the operation of open-loop and closed9 What the abbreviations NO and NC represent CHAPTER PROBLEMS loop control when used to describe switch contacts? 26 What is a seal-in circuit? L1 L2 10 Draw the electrical symbol used to represent each Design and draw the schematic for a conventional 27 circuit In what is the construction and operation of anRun hardwired relay thatway will perform each of of the following switches: electromechanical latching relay different Stop from a the following circuit functions when a normally OL a NO pushbutton switch M closed pushbuttonstandard is pressed:relay? b NC pushbutton switch • Switch a pilot light on 28.a solenoid Give a short description of each of the following Jog M c Break-make pushbutton switch • De-energize control processes: d Three-position selector switch • Start a motor running • Sound a horn a Sequential e NO limit switch Figure 6-78 Hardwired control circuit for Problem Design and draw the schematic for a conventional b Combination f NC temperature switch will correctly execute the hardwired control circuit hardwired circuit that will perform the following c Automatic g NO pressure switch in Figure 6-78 circuit functions using two break-make pushbuttons: h NC level switch 29 L1Compare the type ofissensor a Assume:from Stop pushbutton used is an NO type • Turn on light when pushbutton PB1 pressed.signal obtained i NO proximity switch with from an RTD Run pushbutton used is an NO type • Turn on light L2thermocouple when pushbutton PB2that is pressed Jog pushbutton used has one set of NO • Electrically the pushbuttons so that reed L1 float switch works 11 Outline the method used to actuate inductive and 30.interlock Explain how a magnetic contacts and L2 cannot both be turned on at the same time capacitive proximity sensors 31 logic Whatprogram is the function of anand electrical interlocking OL contact is hardwired Study the ladder in Figure 6-77, 12 How are reed switch sensors actuated? circuit? Design a PLC program and prepare a typical I/O answer the questions that follow: diagram and ladder logic program that a Under what the role latch of rung be true? 13 Compare the operation of a photovoltaic solar cell 32.condition What will is the instrumentation inconnection an industrial will correctly execute the hardwired control circuit b Under what conditions will the unlatch rung be true? with that of a photoconductive cell process? in Figure 6-79 c Under what condition will rung be true? 14 What are the two basic components of a photoelec33.is on, You assigned anpushbutton used is an NO type Assume: PB1 d When PL1 thehave relay been is in what state the task of calibrating tric sensor? PB2 pushbutton used is an NC type (latched or unlatched)? instrument How would you proceed? 128 Chapter e When PL2 is on, the relay is in what state (latched or unlatched)? f If AC power is removed and then restored to the circuit, what pilot light will automatically Developing Fundamental PLC Wiring Diagrams and Ladder Logic Programscome on when the power is restored? g Assume the relay is in its latched state and all three inputs are false What input change(s) must occur for the relay to switch into its unlatched state? h If the examine if closed instructions at addresses I/1, I/2, and I/3 are all true, what state will the relay remain in (latched or unlatched)? Design a PLC program and prepare a typical I/O of logic chapter concepts connection diagram and ladder program that PS1 pressure switch used is an NO type LS1 limit switch used has only one set of NC contacts L1 Start PB L2 Stop PB CR1 PL1 CR1-1 EXAMPLE PROBLEMS help bring CR1-2 home the applicability SOL PS1 L1 Inputs Ladder logic program I/1 I/1 Rung I/2 Outputs CR2-1 LS1 O/9 L CR2 L2 O/9 SOL PL1 xv SS1 I/2 I/3 Rung O/9 U CR2-2 O/10 PL2 SOL m ANCILLARIES THAT WORK Expanded on and updated from the previous edition, this new edition includes an outstanding instructor support package: • • • ExamView and EZ Test question test banks for each chapter PowerPoint lessons with animations that help visualize the actual process Activity Manual contains true/false, completion, matching, and multiple-choice tests for every chapter in the text So that students get a better understanding of programmable logic controllers, the manual also includes a wide range of programming assignments and additional practice exercises • Answers to the questions and problems in the textbook, Activities Manual, and LogixPro Manual Available on the Instructor Resources section of Connect In addition, for students, this edition also has available: • LogixPro PLC Lab Manual for use with Programmable Logic Controllers Fifth Edition, with LogixPro PLC Simulator This manual contains: • McGraw-Hill’s Connect and Smartbook • LogixPro simulations with audio and video for those using Connect • Over 250 LogixPro student lab exercises sequenced to support material covered in the text xvi m ® Required=Results McGraw-Hill Connect® Learn Without Limits Connect is a teaching and learning platform that is proven to deliver better results for students and instructors Connect empowers students by continually adapting to deliver precisely what they need, when they need it, and how they need it, so your class time is more engaging and effective 88% of instructors who use Connect require it; instructor satisfaction increases by 38% when Connect is required Using Connect improves passing rates by 10.8% and retention by 16.4% Analytics Connect Insight® Connect Insight is Connect’s new one-of-a-kind visual analytics dashboard—now available for both instructors and students—that provides at-a-glance information regarding student performance, which is immediately actionable By presenting assignment, assessment, and topical performance results together with a time metric that is easily visible for aggregate or individual results, Connect Insight gives the user the ability to take a just-in-time approach to teaching and learning, which was never before available Connect Insight presents data that empowers students and helps instructors improve class performance in a way that is efficient and effective Students can view their results for any Connect course Mobile Connect’s new, intuitive mobile interface gives students and instructors flexible and convenient, anytime–anywhere access to all components of the Connect platform m Adaptive THE FIRST AND ONLY ADAPTIVE READING EXPERIENCE DESIGNED TO TRANSFORM THE WAY STUDENTS READ More students earn A’s and B’s when they use McGraw-Hill Education Adaptive products SmartBook® Proven to help students improve grades and study more efficiently, SmartBook contains the same content within the print book, but actively tailors that content to the needs of the individual SmartBook’s adaptive technology provides precise, personalized instruction on what the student should next, guiding the student to master and remember key concepts, targeting gaps in knowledge and offering customized feedback, and driving the student toward comprehension and retention of the subject matter Available on smartphones and tablets, SmartBook puts learning at the student’s fingertips—anywhere, anytime Over billion questions have been answered, making McGraw-Hill Education products more intelligent, reliable, and precise m Programmable Logic Controllers (PLCs) An Overview Image Courtesy of Rockwell Automation, Inc Chapter Objectives After completing this chapter, you will be able to: • • • • Define what a programmable logic controller (PLC) is and list its advantages over relay systems Identify the main parts of a PLC and describe their functions Outline the basic sequence of operation for a PLC Identify the general classifications of PLCs This chapter gives a brief history of the evolution of the programmable logic controller, or PLC The reasons for changing from relay control systems to PLCs are discussed You will learn the basic parts of a PLC, how a PLC is used to control a process, and the different kinds of PLCs and their applications The ladder logic language, which was developed to simplify the task of programming PLCs, is introduced m ... Problems vi 13 1 13 2 13 4 13 5 14 0 14 4 14 7 15 1 15 1 15 6 15 7 15 9 16 2 16 6 17 0 17 3 17 4 17 7 17 9 17 9 Program Control Instructions 9 .1 9.2 9.3 9.4 9.5 Program Control ... 18 4 18 5 18 5 18 8 19 0 19 3 19 5 19 7 200 2 01 2 01 202 203 203 207 208 208 216 2 21 224 226 230 2 31 234 235 236 238 239 240 242 245 247 248 252 253 255 259 264 272 277 277 Contents m Chapter 13 PLC... 2 81 282 284 285 285 287 288 289 2 91 292 292 292 294 294 299 302 302 Part Part 305 306 308 310 311 315 316 322 322 322 325 325 326 326 326 Part Part 328 3 31 332 333 334 334 334 335 336 336 Part