PLC training is a broad term that includes programming, I/O configuration, and industrial networks. Modern Programmable Logic Controllers (PLC’s) can be programmed with several industrial languages with Ladder-Logic being the most popular. Individual manufacturers provide training specific to their brand. There are also books covering the basics as well as forums and websites like this one.
A Word About PLC Programming languages
All the major PLC manufactures adhere to the IEC 61131-3 standard which defines programmable logic controller standards. The IEC standard details such things as Data Types, Variables, Tasks, and Programs.
- Ladder Diagram Graphical programming
- Function Block Diagram Graphical programming
- Structured Text Textual programming
- Instruction List Textual programming
- Sequential Function Chart Graphical programming
This site is dedicated to teaching Ladder Logic based on Allen Bradley’s RSLogix 5000 programming software which operates on ControlLogix, FlexLogix, and CompactLogix PLC’s. The software is capable of programming in Ladder, Function Block, Structured Text, and Sequential Function Chart. If you are just beginning to learn how to program PLC’s this is a great place to start. PLC manufacturers like AB, Siemens, GE Fanuc, and Modicon all adhere to the IEC standard.
PLC Inputs and Outputs
Today’s Programmable Logic Controllers come in all shapes and sizes. Micro-size PLC’s are small with a fixed set of Inputs and Outputs. The I/O can be digital, analog or a mix of both. Mid to large scale PLC’s are modular and can have thousands of I/O points both digital and analog.
Configuring inputs and outputs requires training tailored to specific brands and models. For instance I/O can be local or remote. Local I/O refers to Input and Output cards residing in the same chassis as the PLC. Remote I/O refers to Input and Output cards that reside in a chassis that is connected to the PLC remotely through an industrial network.
I/O configuration is different from one brand to the next. Configuring I/O for an Allen Bradley PLC is completely different then configuring I/O for a Siemens S7 PLC or Modicon controller.
The modern PLC communicates with many peripheral devices including HMI’s, SCADA Systems, programming computers, and a host of other control devices. Ethernet Industrial protocol is quickly becoming one of the most popular choices due to its global usage. Most PLC’s can communicate with any network natively or through a modular device or third party hardware.
The following is an example of some industrial networks
- Industrial Ethernet
In order to be an effective PLC programmer learn one of the programming languages first. This site is an excellent source for learning ladder logic. Although specific to RSLogix 5000 the fundamentals taught here are not brand or platform specific. You can also learn more here, here and here.
Local PLC distributors are an excellent resource for programmable logic controller training. Many distributers have resident experts that provide free or relatively inexpensive training.