[PDF] Programmable Logic Controllers A Practical Approach to IEC 61131-3 using CoDeSys by Dag H. Hanssen

As long as there have been competing producers of PLCs on the market, there have been different programming languages from one PLC brand to another. Even though the same languages, beginning with Instruction Lists (IL) and Ladder diagram (LD), have been used by most of the producers, all of them added their own “dialects” to the languages. When physical
programming terminals replaced software-based programming tools, the differences between languages of the various producers escalated. Several programming languages also saw the light of day. This development was the natural result of the attempt by the producers to make themselves stand out among increasing competition by developing the most user-friendly
languages and tools.

When the IEC 61131-3 standard came out in 1993, the situation started to improve. This standard was the result of the work that had been ongoing for several years in which the best from the various languages and dialects from different producers was assembled into a single document. This is not a rigid standard in the sense that the producers must follow all
requirements and specifications, but more a set of guidelines that the producers could choose to follow to a certain extent. Today, most of the equipment producers have come to realize the advantages of organizing themselves in accordance with the standard. All of the major producers of PLCs, such as Telemecanique, Wago, Mitsubishi, Klockner Moeller, AllenBradley, Omron, Siemens, and so on, have therefore, to a greater or lesser extent, adapted their programming tools to IEC 61131-3.

This book covers close to 100% of the specifications and guidelines that are given in Standard (International Electrotechnical Commission, 2013). The book will therefore be interested to everyone who works with, or wants to learn about programming PLCs, no matter which PLC brand they use.