EPA Real-Time Analysis And Scheduling

Ethernet technology applied in the industrial control has become a research hotspot along with the development of the computer control, communication, network technique. Non deterministic communication delay of Ethernet which can't satisfy the real time request of industrial control has become the main obstacle in application on filed device layer network.EPA (Ethernet for Plant Automation) standard is the first industrial Ethernet standard in China. By analyzing the real time requirement of filed device layer, the real time communication solution that the EPA system is applied in filed device layer is put forward. Based on searching the functions defined by EPA, such as system management, network topology, network communication, clock synchronization and application layer service, this paper pays more attention on the analyzing the real-time performance of EPA system and discussing the real time communication scheduling.-Furthermore, as network nodes, switch cascade connection and bandwidth are fixed on, this paper provides purposes, methods and judgments of deliver time, time synchronization accuracy, throughput, RTE bandwidth and non-RTE bandwidth in EPA system. In addition, it provides reciprocity and testing methods of all the indexes.Developing the platform of EPA system real-time testing, the controlling module DUT5000 is used as the testing equipment with Dynamic C, in the windows, testing interface developed by Visual C++6.0, and designs a visual and graphic node testing software. The software supports link scheduling, real-time communication, the deliver time testing and the time synchronization accuracy testing. The network analysis instrument is utilized to test the performance index of the throughput so that the non-RTE bandwidth can be worked out. The EPA equipments of different factories in 863 Project have been tested by using the platform of EPA system real-time testing, and the results prove the effectiveness of EPA, which provide important assurance for the acceptance of 863 Project.Research and argumentation prove that the real time testing methods are available and correct. The methods provide the references for choosing EPA equipments and network, and have important meanings to the real-time performance of EPA system. The testing methods of this paper can be used in other industry Ethernet.