Timer selection for satisfying the maximum allowable delay using performance model of profibus token passing protocol

Recently, the Fieldbus has become an indispensable component for many automated systems. In the Fieldbus system, realtime data containing sensor values and control commands have a tendency to rapidly lose their value as time elapses after its creation. In order to deliver these data in time, the fieldbus network should be designed to have a short delay compared to the maximum allowable delay. Because the communication delay is affected by performance parameters such as the target rotation timer of token passing protocol, it is necessary to select proper parameter settings to satisfy the real-time requirement for communication delay. This paper presents the timer selection method for Profibus token passing networks using a genetic algorithm to meet the delay requirements.