Distributed Numerical Control System Based On EPA

With the development of information technology and network technology, the development trend of Numerical Control (NC) system are intelligent networking, information and openness. Due to the absence of reliable data-verifying method by using pulse signal or analog signal in data transmission, the traditional way will lead to signal distortion and incertitude of determination once disturbed. Without data transmission between the drivers as a system, the synchronization can also not be guaranteed and improved. Recently, the research on the application of bus technology in NC system has been processing at abroad, such as SERCOS Bus of German and CC-Link Bus of Mitsubishi of Japan which have been pushed into market rapidly with the good performance.Now, the crucial technology of the Ethernet used in the industrial control systems is resolved, including certainty of the network, real time of the network, interoperation of the network, safety of the network, bus-powered, reliability, anti-jamming and so on. Digital data communication for the measurement and control—EPA for using in industrial control systems became the CPF14 (Common Profile Family 14) of the Real Time Standard IEC61784-2.Under this situation, the aim of the project group is to resolve the key problems, including high speed performance, accurate synchronization and high reliability, to meet the required performance and form independent intellectual property bus technology of motion control. So we can reach and surpass the level of international motion control technology by crossing over foreign technical barriers.This paper mainly discussed how to design a distributed NC system based on EPA standard. Through the study on foreign bus technology and the combination with the characteristics of communication in EPA, we have studied and improved the COSMO 122T NC system of electrical corporation on the base of development platform. The author has designed the EPA communication module and the embedded connecting circuit. According to the servo drive of the electric company .The study and design of target point track interpolation algorithm on ARM have also been done in this paper.The designed system eliminates the disadvantage of collision in traditional Ethernet by making full use of the deterministic communication scheduling mechanism of EPA in communication. And it meets the requirements in synchronization by using accurate clock synchronal protocol. Networking of the whole system is flexible by using distributed structure. It also offers a platform to improve performance and a good foundation for function extension.