Coupling and Decoupling in IEC 61499 and IEC 61131-3 Applications

The history of the software industry has shown and proved that coupling and cohesion are a never-ending story in this industry. Quantifying the quality of software systems by measuring the strength of coupling and cohesion and considering it a rule that good software has low coupling between its parts and high cohesion within each part, is currently widely accepted. Every paradigm shift, new technology, language, etc. that didn`t consider this fact had to sooner or later leave this industry. It is, therefore, crucial to study and consider this fact in every new topic in the software industry. Surprisingly neither the IEC 61499 nor IEC 61131 communities have yet conducted a deep study to evaluate what coupling and cohesion really mean for Industrial Control and Automation Applications. We hope this paper will manage to fulfill this considerable gap, if not fully at least partially.