PLC Hardware, Wiring, and Ladder Logic Fundamentals

This senior-level course provides a comprehensive and technically rigorous introduction to Programmable Logic Controllers (PLCs), essential components in modern industrial automation and control systems. Students will gain a deep understanding of PLC architecture, including CPU, I/O modules, power supplies, and communication interfaces. Emphasis is placed on the practical aspects of PLC implementation, covering proper wiring techniques for various sensors and actuators, understanding industrial control panels, and adhering to safety and electrical codes relevant to PLC installations. The course balances theoretical concepts with hands-on application, preparing students for real-world engineering challenges. A significant portion of the course is dedicated to ladder logic programming, the predominant language for PLCs. Students will learn to develop, simulate, and debug ladder logic programs for common industrial control tasks such as motor control, sequencing, and process automation. Topics include fundamental instructions (contacts, coils, timers, counters), advanced instructions (arithmetic, data manipulation), and structured programming techniques. Through laboratory exercises and a culminating final project, students will apply their knowledge to design and implement robust and efficient PLC-based control solutions, fostering critical thinking and problem-solving skills vital for electronics engineers in industrial settings.

Course outline

Lectures, virtual labs, and graded assignments — completed in your browser.

01Introduction to PLCs and Industrial Automationlecture

02PLC Hardware Architecture and Componentslecture

03Discrete I/O Wiring and Field Deviceslecture

04Analog I/O, Scaling, and Transducerslecture

05Industrial Control Panels and Electrical Safetylecture

06Ladder Logic Fundamentals: Contacts, Coils, and Latcheslecture

07Timers and Counters: Industrial Control Elementslecture

08Midterm examassignment

09Data Handling and Arithmetic Operationslecture

10Program Control and Comparison Instructionslecture

11Sequential Control and State Machine Designlecture

12PLC Communications and Network Protocolslecture

13Troubleshooting and Best Practices in PLC Programminglecture

14Final projectassignment

Syllabus

Course Objectives: Upon successful completion, students will be able to: 1) Identify and explain the functional components of a modern PLC system. 2) Design and correctly wire PLC input/output modules to various industrial sensors and actuators. 3) Develop, test, and debug ladder logic programs for a range of industrial control applications. 4) Apply structured programming principles to create robust and maintainable PLC code. 5) Analyze and troubleshoot common PLC hardware and software issues. 6) Understand and adhere to industrial safety and electrical standards relevant to PLC installations.

Topics by Week:
Week 1: Introduction to PLCs, History, and Applications in Industry.
Week 2: PLC Hardware Architecture: CPU, Memory, Power Supply.
Week 3: Discrete I/O Modules: Sourcing/Sinking, Wiring Standards.
Week 4: Analog I/O Modules, Scaling, and Signal Conditioning.
Week 5: PLC Wiring Practices, Industrial Panels, Safety, and NEC Basics.
Week 6: Introduction to Ladder Logic, Basic Instructions (NO, NC, Coil).
Week 7: Timers and Counters: On-Delay, Off-Delay, Retentive, Up/Down.
Week 8: Midterm Exam.
Week 9: Data Handling and Math Instructions: Move, Add, Subtract, Multiply, Divide.
Week 10: Compare and Logical Instructions, Program Control (JMP, LBL, MCR).
Week 11: Sequential Control and State Diagrams, Structured Programming.
Week 12: HMI/SCADA Overview, PLC Networking and Communication Protocols.
Week 13: Advanced PLC Functions and Troubleshooting Techniques.
Week 14: Final Project Presentations and Demonstrations.

Grading Policy: Homework/Quizzes (20%), Lab Exercises/Reports (30%), Midterm Exam (20%), Final Project (30%).