PLC standard programming languages: IEC 1131-3

Today, if programmable controllers from more than one vendor are used, more than one method of programming and troubleshooting have to be learned. If a programming standard provided greater uniformity between programmable controllers, one could reuse work and potentially reduce the amount of retraining. Yet the problem for the would-be developer of standards is this: how to offer relevance to today's market and still afford migration to future technologies. IEC 1131-3-the international standard for programmable controller languages-has achieved this by applying modern software engineering principles to the best existing practices and, at the same time, providing for "extensibility", i.e. further enhancements by vendors. The author describes the development and benefits of IEC 1131-3.