AC500-S Safety PLC Application Note: Triggering Safety Actions with Standard HMI

This application note presents a method for using a standard (non-safety) Human Machine Interface (HMI) to trigger safety actions, such as selecting substations or pre-defined safely limited values, with an AC500-S safety PLC while satisfying PL d (ISO 13849-1) requirements. It includes an example with functional safety calculations, addressing drawbacks of traditional mechanical mode selector switches by offering improved user-friendliness, flexibility, and reduced costs.