A Variable Priority Token-passing Fieldbus based on Quality of Service

In Fieldbus network control system, the upper core computer acts as the supervisor and processes all the data transferred from network nodes. As the coordinator, the working efficiency of the network communication is the key factor of the whole system. The purpose of this paper is to solve the media access control issue in fieldbus system. A novel variable priority token passing data communication manner for the media access control in fieldbus is presented on the base of QoS (Quality of Service). The mathematic analysis results suggest its efficiency and advantages over the CSMA/CD and standard token-passing manners.