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).