Programmable Logic Controllers Principles And Applications By John W Webb.pdf May 2026

"Programmable Logic Controllers: Principles and Applications" by John W. Webb is a foundational text in industrial automation that bridges traditional hard-wired relay logic with modern digital control systems. The book emphasizes fundamental automation principles through extensive use of ladder logic, hardware architecture, and practical, real-world application examples for technicians and engineers.

• The hardware examples reference obsolete models (AB PLC-5, Modicon 984).
• Software screenshots look like Windows 95.
• No coverage of Ethernet/IP, PROFINET, Safety PLCs, or IIoT.

Part 2: Ladder Logic Fundamentals

• Contacts and Coils: Understanding Normally Open (NO) and Normally Closed (NC) symbols.
• Timers and Counters: On-delay (TON), Off-delay (TOF), retentive timers, up/down counters.
• Arithmetic and Data Move: How PLCs handle math operations for process control.

Part 4: Installation and Troubleshooting

• Electrical Noise and Grounding: The real-world electrical issues that fry PLCs.
• Fault Diagnostics: Using the PLC to find broken wires or failed sensors.
• Preventative Maintenance: How to prolong the life of a controller.