IEC 61131-3 sekvenssidiagrammi-standardin parantaminen nykyajan automaation tarpeisiin

IEC 61131-3 standard defines the programming languages that are used to program programmable logic controllers. Among those languages is Sequential Function Chart, that can be used to configure sequential controls. Sequences can be used to control anything that needs to be executed sequentially one step at a time. Some example use cases for sequential control are washing machine washing cycle, controlling traffic lights or transitioning a machinery from on to off. In this thesis, the goal was to find how the standard could be improved to better fit the cases it is used for. The main research method was interviewing engineers that have some experience in configuring sequences. The interviews were conducted as semi-structured interviews to get the most out of the users of the tools that implement the standard. Some of the most important features that were missing from the standard were the lack of special error handling, a simple way to define non-Boolean actions and too permitting branch execution. There were also a lot of small implementation details that is worthwhile to consider when implementing the standard. The most important being the translation between structured text and SFC and the amount of details that are shown in the diagram without making it too cluttered