Introduction to Programmable Logic Controllers

by Dunning,Gary A.

• ISBN13: 9780766817685
• ISBN10: 0766817687
• Format: Paperback
• Copyright: 2001-08-01
• Publisher: Cengage Learning

Summary

Now in its second edition, Introduction to Programmable Logic Controllers contains an all-new chapter on micro PLCs as well as newly available, manufacturer-specific photos to illustrate principles of PLC operation. Updated to include recent industry innovations, and expanded as a result of reader feedback, this book begins with an orientation to the general principles underlying all PLC operations which features leading manufacturers such as General Electric, Omron, Mitsubishi, and Seimens. Subsequent chapters invite readers to delve into the Rockwell Automation/Allen-Bradley SLC 500 family of PLCs, exploring their operation and instruction set(s) in detail. A well-engineered, fully integrated supplement package is also available for educators and trainers seeking to use this book to deliver a professional-level, hands-on PLC learning experience with minimal advanced preparation.

Table of Contents

Preface	p. ix
Acknowledgments	p. xi
Introduction to PLCs
Welcome to the World of Programmable Logic Controllers	p. 3
What Is a Programmable Logic Controller (PLC)?	p. 4
Where Did the PLC Come From?	p. 5
Why Use a PLC?	p. 6
What Makes a PLC Work?	p. 8
How Do PLCs Know What They Are Supposed to Do?	p. 8
How Do Instructions Get into the PLC's Memory?	p. 9
Innovations Incorporated into the Programmable Controller	p. 11
Introduction to Fixed and Modular PLC Hardware	p. 16
The Central Processing Unit	p. 23
Micro Programmable Logic Controllers	p. 31
Overview of Selected Micro PLCs	p. 33
GE Fanuc Automation VersaMax Controllers	p. 33
GE Fanuc Automation Series 90 Micro PLC	p. 37
The Mitsubishi FX2N Super Micro	p. 39
Omron's CPM1A Series Micro PLC	p. 44
Rockwell Automation's MicroLogix 1000 Microcontroller	p. 45
Rockwell Automation's MicroLogix 1500 Microcontroller	p. 46
Siemens Simatic S7-200 Micro PLC	p. 50
Programming a Programmable Controller	p. 57
Handheld Programming Terminals	p. 58
Desktop Personal Computers (PCs) and PLC Programming	p. 63
Notebook Personal Computers and PLC Programming	p. 68
Windows CE-based Handheld Personal Computers	p. 71
Industrial Computers	p. 73
Industrial Monitors	p. 77
Open PLC Systems	p. 77
The IEC 1131-3 Programming Standard	p. 78
Soft PLC or Open-architecture Control	p. 88
One Step Further: Production Data from PLC to Office Databases	p. 88
Number Systems	p. 95
Number System Characteristics	p. 96
The Decimal Number System	p. 97
Decimal Place Values	p. 97
Binary and Binary-coded Decimal Numbers	p. 98
Binary Numbers	p. 98
Bit Position and Weighting	p. 99
Binary Coding	p. 100
Binary-coded Decimal (BCD) Numbers	p. 102
BCD Number Representation of Numbers Between 10 and 99	p. 105
BCD Representation of the Decimal Numbers 100 through 999	p. 106
BCD Representation of Four-digit Decimal Values	p. 106
Applications of BCD	p. 106
The Octal Number System	p. 108
Valid Octal Numbers	p. 108
Octal-to-decimal Conversion	p. 109
Binary-to-octal Conversion	p. 110
Octal-to-binary Conversion	p. 111
The Hexadecimal Number System	p. 111
Introduction to PLC Operation	p. 119
The Digital Concept	p. 120
Analog Signals	p. 121
The Binary Concept	p. 122
Binary Data Representation	p. 123
Correlation of 16-bit Words to Input Signals	p. 124
The Input Status File	p. 128
The Output Status File	p. 129
Input and Output Status Files and Fixed PLCs	p. 131
Differentiating One I/O Screw Terminal from Another	p. 133
Sixteen-point I/O Modules with Decimal Addressing	p. 135
I/O Interaction with the Input and Output Status Files	p. 137
Fixed PLC I/O Addressing When I/O Is Expanded	p. 140
PLC Memory and How It Is Used	p. 141
Data Formats	p. 141
PLC System Memory	p. 145
PLC Application Memory	p. 146
Introduction to Logic	p. 153
Conventional Ladders versus PLC Ladder Logic	p. 153
What is Logic?	p. 156
Overview of Logic Functions	p. 157
Series--The AND Logic Function	p. 158
Three-input AND Logic	p. 160
Parallel Circuits--The OR Logic Function	p. 162
NOT Logic	p. 164
Analysis of Rung #1	p. 165
Analysis of Rung #2	p. 165
Parallel NOT Logic	p. 166
Exclusive OR Logic	p. 167
Analysis of Exclusive OR Logic	p. 168
Combinational Logic	p. 169
Priority of Logic Elements	p. 170
Input Modules	p. 177
Input Modules	p. 178
Discrete Input Module	p. 180
Discrete AC Input Module	p. 180
AC Input Module Specifications	p. 183
DC Input Modules	p. 189
Sinking and Sourcing	p. 190
DC Input Module Operation	p. 194
DC Sinking Input Module Specifications	p. 195
Solid-state Sensor Interface to DC Input Modules	p. 198
A Final Note on Sinking and Sourcing	p. 200
Analog Inputs	p. 200
Specialty Modules	p. 208
Output Modules	p. 215
Discrete Output Modules	p. 216
Transistor-Transistor Logic (TTL) Output Modules	p. 221
Relay Output Modules	p. 221
Module Selection Considerations	p. 226
Choosing the Proper Output Module	p. 227
Isolated Output Modules	p. 228
Interposing Relays	p. 228
Surge Suppression and Output Modules	p. 230
High-density I/O Interface	p. 231
Analog Outputs	p. 231
Emergency-stop Switches and PLC Applications	p. 232
I/O Modules in Hazardous Locations	p. 234
Hardware Considerations Before Installing PLCs in Class 1, Division 2, Areas	p. 235
Putting Together a Modular PLC	p. 241
Racks, Chassis, or Baseplates	p. 242
The Local, or Base, PLC	p. 248
Local Expansion	p. 248
Remote I/O Expansion	p. 249
PLC Networking	p. 251
Selection and Placement of I/O Modules	p. 251
Power Supply Selection	p. 253
I/O Racks and Expansion	p. 263
PLC Processors	p. 275
The Processor's Function	p. 276
The Processor's Operating System	p. 276
Processor Scanning	p. 279
Omron CQM1 Operating Cycle	p. 281
The Watchdog Timer	p. 283
Processor Ports	p. 285
The RS-232C Communication Standard	p. 287
Serial Communication Between a Personal or Industrial Computer and the PLC	p. 288
Interfacing to non-RS-232 PLC Processors	p. 292
Processor-operating Modes	p. 292
On-line Editing	p. 295
Battery Backup for the Processor's Volatile Memory	p. 295
Lithium Battery Handling and Disposal	p. 297
Nonvolatile Memory: Eeprom	p. 298
Passwords	p. 299
The Allen-Bradley SLC 500 Modular Processors	p. 301
Rockwell Automation's Logix 5550 Controller	p. 308
The General Electric Series 90-30 Processors	p. 310
Choosing the Correct Processor for an Application	p. 318
PLC Instructions
Processor Data Organization	p. 327
SLC 500 Files	p. 328
Data Files	p. 330
User-defined Files	p. 339
The Basic Relay Instructions	p. 347
Bit, or Relay, Instructions	p. 348
The Normally Open Instruction	p. 348
The Output Instruction	p. 349
Modular SLC 500 Instruction Addressing	p. 350
The Normally Closed Instruction	p. 352
The One-shot Instruction	p. 354
The Output-latching Instruction	p. 356
The Negated Output Instruction	p. 359
Internal Bit-type Instructions	p. 359
Understanding Relay Instructions and the Programmable Controller Input Modules	p. 367
Interfacing a Start-stop Push-button Station to a Programmable Controller	p. 371
User Program Development for a Start-stop, Push-button Interface	p. 374
Motor Starter Circuits and the Overload Contacts	p. 381
Special Considerations for PLC Control of Motor Starters	p. 382
Documenting Your PLC System	p. 387
Why Add Documentation to User Program?	p. 388
Information to Include in PLC Documentation	p. 388
Documentation and Software Packages	p. 390
Types of Documentation	p. 391
Adding Documentation When Developing a New Application	p. 397
Timer and Counter Instructions	p. 409
Timer Instructions	p. 410
SLC 500 Timers	p. 410
The On-delay Timer Instruction	p. 413
The Off-delay Timer Instruction	p. 415
The Retentive Timer Instruction	p. 416
The Reset Instruction	p. 418
PLC Counter Instructions	p. 418
Allen-Bradley SLC 500 Counters	p. 420
How Counters Work	p. 422
The Count-up Instruction	p. 423
The Count-down Instruction	p. 424
The High-speed Counter Instruction	p. 426
The Counter Reset Instruction	p. 426
The Clear Instruction	p. 427
Combining Timers and Counters	p. 428
Comparison and Data-Handling Instructions	p. 435
Comparison Instructions	p. 436
Data-handling Instructions	p. 440
Logical Instructions	p. 452
Sequencer Instructions	p. 467
The Sequencer	p. 468
Sequencer Instructions	p. 468
The SLC 500 Sequencer Output Instruction	p. 469
Programming the Sequencer Output Instruction	p. 475
Multiple Sequencers and File Designation	p. 476
Applying Hexadecimal Numbers and Masks With SLC 500 Programming Instructions	p. 477
Mask Data Representation	p. 480
Instruction Set Reference	p. 485
Status File Overview	p. 491
Applying Hexadecimal Numbers in PLC Masking Applications	p. 495
Glossary	p. 499
Index	p. 510
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