Profinet IO IRT Message Scheduling

This paper presents an algorithm that allows one to create a static schedule of the Profinet IO IRT communication, which is an industrial Ethernet protocol standardised in IEC$\;$61158. This algorithm offers an alternative to the available commercial tool, providing comparable results regarding the resulting time schedule length. Furthermore, we extend the problem by useful time constraints providing a greater flexibility with respect to the individual messages. Due to this flexibility, it is possible to place the selected messages in various parts of the communication cycle, to define end-to-end delays, or to increase the computational time available for the main-controller application, for example. The solution is based on a formulation of the Profinet IO IRT scheduling problem in terms of the Resource Constrained Project Scheduling with Temporal Constraints (PS|temp|Cmax).