Programmable Controllers: An Engineer's Guide

✍ Scribed by E. A. Parr

• Publisher: Newnes
• Year: 2003
• Tongue: English
• Leaves: 443
• Edition: 3
• Category: Library

✦ Synopsis

Andrew Parr's Programmable Controllers provides a thoroughly practical introduction to the use of PLCs in industry, covering programming techniques alongside systems-level design issues. In the third edition a masterclass series of real-world case studies have been added to illustrate typical engineering challenges - and model solutions. New material also includes the new IEC-61508 functional safety standard, use of Windows-based software on programming terminals, an expanded section on Scada, and extended coverage of networks and fieldbus. Andrew Parr works at ASW Sheerness Steel where the plant control is based on approximately sixty programmable controllers. * The practical guide to PLC applications for engineers and technicians * Systems-level design and control covered alongside programming techniques * Coverage matched to introductory college programs

✦ Table of Contents

Contents......Page 6
Preface......Page 12
1.2 Types of control strategies......Page 14
1.2.2 Sequencing subsystems......Page 15
1.2.3 Closed loop control subsystems......Page 17
1.2.4 Control devices......Page 18
1.3 Enter the computer......Page 19
1.3.1 Computer architectures......Page 20
1.3.3 High level languages......Page 24
1.3.5 Requirements for industrial control......Page 27
1.3.6 The programmable controller......Page 31
1.4.1 Input cards......Page 34
1.4.2 Output connections......Page 35
1.4.3 Input/output identification......Page 41
1.5 Remote I/O......Page 42
1.6 The advantages of PLC control......Page 44
2.1 Introduction......Page 46
2.2 The program scan......Page 49
2.3.1 Racks, cards and signals......Page 53
2.3.2 Allen Bradley PLC-5......Page 54
2.3.4 CEGELEC GEM-80......Page 55
2.3.5 ABB Master......Page 58
2.3.6 Mitsubishi F2......Page 60
2.4.1 Introduction......Page 61
2.4.2 Ladder diagrams......Page 62
2.4.3 Logic symbols......Page 65
2.4.4 Statement list......Page 68
2.5 Bit storage......Page 71
2.6 Timers......Page 76
2.7 Counters......Page 80
2.8.1 Numeric representations......Page 85
2.8.2 Data movement......Page 88
2.8.3 Data comparison......Page 90
2.8.4 Arithmetical operations......Page 91
2.9.1 Combinational logic......Page 94
2.9.2 Event-driven logic......Page 99
2.10 Micro PLCs......Page 108
2.11 IEC 1131-3, towards a common standard......Page 112
2.12 Programming software......Page 118
2.13 Programming software tools......Page 122
3.1 Introduction......Page 128
3.2 Software engineering......Page 129
3.3 Top-down design......Page 131
3.4 Program structure in various PLCs......Page 132
3.5 Housekeeping and good software practice......Page 141
3.6 Speeding up the PLC scan time......Page 148
4.2.1 Temperature......Page 153
4.2.2 Pressure......Page 155
4.2.3 Flow......Page 157
4.2.5 Weighing systems......Page 159
4.2.6 Level......Page 160
4.2.7 Position......Page 161
4.3 Signals and standards......Page 162
4.4.1 Resolution......Page 164
4.4.2 Multiplexed inputs......Page 165
4.4.3 Conversion times......Page 166
4.4.4 Channel selection and conversion to engineering units......Page 169
4.4.5 Analog input cards......Page 171
4.5 Analog output signals......Page 173
4.6 Analog-related program functions......Page 176
4.7.1 Introduction to control theory......Page 177
4.7.2 Stability and loop tuning......Page 180
4.7.3 Closed loop control and PLCs......Page 181
4.8 Specialist control processors......Page 185
4.9 Bar codes......Page 186
4.11 Intelligent modules......Page 191
4.12 Installation notes......Page 192
5.1 Parallel and serial communications......Page 195
5.2.2 Synchronization......Page 198
5.2.4 Transmission rates......Page 199
5.2.5 Modulation of digital signals......Page 202
5.2.6 Standards and protocols......Page 204
5.2.7 Error control......Page 209
5.2.8 Point to point communication......Page 215
5.3.2 Transmission lines......Page 218
5.3.3 Network topologies......Page 220
5.3.4 Network sharing......Page 222
5.3.5 A communication hierarchy......Page 223
5.4 The ISO/OSI model......Page 225
5.5.1 Introduction......Page 227
5.5.2 Allen Bradley Data Highway......Page 228
5.5.3 Gem-80 Starnet, ESP and CORONET......Page 230
5.5.5 Ethernet......Page 231
5.5.6 Towards standardization......Page 232
5.5.7 Profibus......Page 236
5.6 Safety and practical considerations......Page 237
5.7 Fibre optics......Page 240
6 The man–machine interface......Page 0
6.1 Introduction......Page 245
6.2 Simple digital control and indicators......Page 247
6.3.1 Numerical outputs......Page 249
6.3.2 Multiplexed outputs......Page 250
6.3.4 Numerical inputs......Page 253
6.4 Alarm annunciation......Page 255
6.5 Analog indication......Page 260
6.6.1 Introduction......Page 263
6.6.2 The Allen Bradley Panelview......Page 267
6.6.3 Pixel graphics; the CEGELEC Imagem......Page 269
6.6.4 The Siemens Simatic HMI family......Page 278
6.6.5 Practical considerations......Page 280
6.6.6 Data entry......Page 283
6.8 SCADA packages......Page 284
7.1 Introduction......Page 289
7.2.1 Introduction......Page 290
7.2.2 IEEE-488 parallel interface bus......Page 291
7.2.3 Backplane bus systems......Page 294
7.2.4 IBM PC clones......Page 295
7.3 Programming for real time control......Page 298
7.4 Soft PLCs......Page 305
8.2.1 Introduction......Page 306
8.2.2 Risk assessment......Page 307
8.2.3 PLCs, computers and safety......Page 309
8.2.4 Emergency stops......Page 321
8.2.5 Guarding......Page 325
8.2.6 Safety legislation......Page 327
8.2.7 IEC 61508......Page 328
8.3 Design criteria......Page 333
8.4.1 Power supplies......Page 335
8.4.2 Equipment protection......Page 338
8.5.1 Introduction......Page 344
8.5.2 Statistical representation of reliability......Page 345
8.5.3 Maintenance philosophies......Page 348
8.5.4 Designing for faults......Page 350
8.5.5 Documentation......Page 352
8.5.6 Training......Page 357
8.5.7 Fault-finding aids, EDDI and FlMs......Page 361
8.6 Electromagnetic compatibility (EMC) and CE marking......Page 367
Table 8.7......Page 370
8.7 Other programmable devices......Page 372
9.1 Introduction......Page 375
9.2 One Shot......Page 377
9.3 Toggle action......Page 378
9.4 Alarm annunciator......Page 381
9.5 First order filter......Page 383
9.6 Level control......Page 386
9.7 Linearization......Page 393
9.8 Flow totalization......Page 398
9.9 Scaling......Page 404
9.10 Gray code conversion......Page 407
9.11 BCD to Binary conversion......Page 411
9.12 Binary to BCD conversion......Page 413
9.13 A hydraulic system......Page 416
Appendix Number systems......Page 429
Index......Page 434