Introduction to Programmable Logic Controllers - Part I

Chong Chen, Ph.D., P.E.


Course Outline

A Programmable Logic Controller (PLC) is a device that is capable of being programmed to perform control functions. The first PLC was introduced in the late 1960s to replace relay logic controls in the automotive industry. Compared to relay logic controls, the PLC's advantages include easy programming and installation, high control speed, hardware and software security, network compatibility, troubleshooting and testing convenience, and high reliability.

PLCs are currently used widely in industrial and commercial environments. They can be found in almost any manufacturing facility. There are several manufacturers of PLCs. While the instruction formats may not be the same for different brands, the hardware structures and programming concepts are very similar. This course covers PLC hardware structure, input/output modules, software, and programming. PLC operation and ladder logic programs are discussed.

This course includes a multiple-choice quiz at the end, which is designed to enhance the understanding of the course materials.


Learning Objective

At the conclusion of this course, the student will:

  • Learn the major components of a Programmable Logic Controller (PLC);
  • Learn the functions of the CPU, input modules, and output modules in a PLC;
  • Be familiar with binary number and decimal number systems;
  • Be able to covert a binary number to decimal number and vice versa;
  • Learn basic logic functions: AND, OR, and NOT;
  • Be familiar with the operation and scan cycle of a PLC;
  • Learn bit instructions and their functions;
  • Be able to use bit instructions for PLC programming;
  • Learn timer instructions and their functions;
  • Be able to use timers for PLC programming;
  • Learn counter instructions and their functions; and
  • Be able to use counters for PLC programming.


Course Content

This course is the first part of a two-part course on Programmable Logic Controllers. There are a total of six modules in the two-part course. Part I covers Modules 1 through 4. Modules 1 and 2 are independent. Modules 3 through 6 are in sequence. The first two modules should be studied before the other modules.

Course Modules - Part I (PDF Format)

Module 1: Introduction to PLC Hardware

Module 2: Number Systems and Logic Functions

Module 3: PLC Ladder Logic Program, Scan Operation, and Bit Instructions

Module 4: Timers and Counters


The above course modules are in PDF format. You need to open or download those documents to study this course.

For your convenience or for better graphic quality, you may also download the same modules in MS Word format.

Course Modules - Part I (MS Word Format)

Module 1: Introduction to PLC Hardware

Module 2: Number Systems and Logic Functions

Module 3: PLC Ladder Logic Program, Scan Operation, and Bit Instructions

Module 4: Timers and Counters


References

1. Allen-Bradley: Advanced Programming Software User's Manual.

2. David A. Geller: Programmable Controllers Using the Allen-Bradley SLC-500 Family, Prentice Hall.

3. Colin D. Simpson: Programmable Logic Controllers, Prentice Hall.

 

Once you finish studying the above course content you need to take a quiz to obtain the PDH credits.

Take a Quiz


DISCLAIMER: The materials contained in the online course are not intended as a representation or warranty on the part of PDHonline.com or any other person/organization named herein. The materials are for general information only. They are not a substitute for competent professional advice. Application of this information to a specific project should be reviewed by a registered professional engineer. Anyone making use of the information set forth herein does so at their own risk and assumes any and all resulting liability arising therefrom.



 
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