Introduction
IEC 1131-3 is the first real endeavour to standardize programming languages for industrial automation. With its world wide support, it is independent of any single company. IEC 1131-3 is the third part of the IEC 1131 family. This consists of:
- Part 1: General Overview
- Part 2 Hardware
- Part 3 Porgramming Languages
- Part 4 User Guidelines
- Part 5 Communication

Programming Languages
Within the standard four programming languages are defined. This means that their syntax and semantics have been defined, leaving no room for dialects. Once you have learned them, you can use a wide variety of systems based on this standard. The languages consist of two textual and two graphical versions:

Textual:
   - Instruction List, IL
   - Structured Text, ST

Graphical:
   - Ladder Diagram, LD
   - Function Block Diagram, FBD


                        

Conclusions
The technical implications of the IEC 1131-3 standard are high, leaving enough room for growth and differentiation. This makes this standard suitable to evolve well into the next century. IEC 1131-3 will have a great impact on the whole industrial control industry. It certainly will not restrict itself to the conventional PLC market. Nowadays, one sees it adopted in the motion control market, distributed systems and softlogic / PC based control systems, including SCADA packages. And the areas are still growing. Having a standard over such a broad application area, brings numerous benefits for users / programmers. The benefits for adopting this standard are various, depending on the application areas. Just to name a few for the mindsetting:
1- Reduced waste of human resources, in training, debugging, maintenance and consultancy
2- Creating a focus to problem solving via a high level of software reusability
3- Reduced misunderstanding and errors
4- Programming techniques usable in a broad environment: general industrial control
5- Combining different components from different programs, projects, locations, companies and/or countries departamentos y compañías.

Interesting Links
www.plcopen.org.