Programmable Logic Controllers: An Emphasis on Design and Application

The complete reference for PLC programming - updated. This book presents a comprehensive treatment of programmable logic controllers (PLCs) with an emphasis on program design. This text stresses an organized approach to developing PLC programs - Given a set of operational specifications, how does one develop the PLC program? This book develops the design process: the tasks involved, breaking the program into manageable pieces, standard code for the various parts, and handling the sequential parts of the problem. Throughout, the book contains example problems demonstrating good design practice and culminates in two full-length case studies. Due to its popularity, ladder logic is employed in the majority of the text. However, the text also comprehensively covers the other four IEC 61131-3 languages: function block diagram, structured text, instruction list, and sequential function chart. These languages are covered for five PLCs: Allen-Bradley ControlLogix, Allen-Bradley MicroLogix/SLC-500, Siemens S7, Modicon, and Emerson/GE. The main topics of this text are: 1. PLC programming languages (with emphasis on ladder logic) 2. Structured approach to sequential problems 3. Good program design practice 4. Troubleshooting techniques 5. PID control 6. Sensors and actuators 7. Factory communication networks 8. Human-machine interface (HMI) Most chapters include student problems. There is a companion website with supplementary material.
Changes for the Fourth Edition
The fourth edition primarily updates the Rockwell, Siemens, and former GE processors, but there are other changes throughout. The major changes are: 1. The former GE PLCs are now branded as Emerson PLCs. 2. The appearance of the ControlLogix blocks is changed to match the modifications introduced in Logix Designer revision 31. Addressing for 5069- and 5094-series I/O modules has been added to Chapter 3 and new ControlLogix blocks related to process control have been added to Chapter 10. 3. The Siemens S7-1500 CALCULATE block, introduced in version 14, has been added to Chapter 7. An implementation of the S7-300/400 FIFO/LIFO blocks that were not ported to the S7-1500 are described in Chapter 8 and implemented in the SCL language in Chapter 12. New S7-1500 blocks for process control are described in Chapter 10. 4. In Chapter 9, the move-based implementation of sequential operations is added and the section on sequencer blocks is removed. 5. Chapter 19 is updated for changes in the security features of the processors. 6. The implementation of sequential operations in Chapter 21 is changed to the move-based sequencer. In addition, simulation of the process with the ControlLogix and S7-1500 processors is changed to add (and emphasize) module inhibits. 7. The multi-unit chemical process in Chapter 22 is now larger.