Design And Development Of Communication Module Of EPA Field Controller

In recent years, the advantage of Industrial Ethernet has been materialized increasingly. Interiorly, EPA is a very preponderant protocol in the Industrial Ethernet, and it has gained a very illustrious success in recent years. And in 2005, EPA has become a number of IEC61158. With the rapid development of EPA, the design and development of the EPA field device, EPA field controller and EPA Bridge are very necessitous now. The field controller is a very important part of the EPA control system and it plays a very important role in the system.The communication module of EPA field controller is used as the study object in this dissertation. This dissertation deeply studied in the design of the real-time OS, the clock synchronization method, the communication schedule method, the high pricise timer array and the realtime network redundancy.In current system, to design a stable and precise communication schedule module is the main target of the field controller's design, and the design of clock synchronization and timer array is the base of the communication schedule module. So the clock synchronization module, communication schedule module and the timer array module are the emphases of this dissertation. Through the analysis of the synchronization system, some way to improve the synchronous system in fieldwork was put forward and was deeply discussed in the 4th chapter. And we use the delta-method to build a high precise timer array in the system. At last the communication schedule's precision is very high. The precision is much accurater than the designed goal. And in order to improve the stability of the communication module, a realtime network redundancy module was added to the system. These provide a very stable base for the system.Firstly, this dissertation introduced the history and the latest information of Industrial Ethernet. The research and development of the EPA system is the emphasis of this dissertation. In the 3th and 4th chapters, the hardware design and software design of the EPA protocol is studied. The main part of the hardware design is about communication circuit design and Reset circuit design. The software design is present in 5 parts: The OS design, clock synchronization design, communication schedule design, system timer array design realtime network redundancy module and DPram module design. The development and stablility test, communication test were carriedthrough, and we get a satisfying result. Now the EPA field controller has run in the first and second demonstration applications in Huadong medical factroy and the run-time result is satisfying.