With the rapid development of information network technology today, the traditional fieldbus techniques have been unable to meet the needs of industrial control systems. Industrial Ethernet is playing a more and more important role in industrial control network. Industrial Ethernet has a series of advantages like high communication rate, good openness, good real-time performance, low cost and resource sharing capability, which perfectly meet the requirements of communication in network control system. Ethernet POWERLINK is a typical real-time Industrial Ethernet, which is built on the standard Ethernet. Its real-time performance is impressive, the protocol is open source, and suitable for a variety of platforms, which gives it extensive application prospect in industrial control field. This paper analyses the structure, communication mechanism and performance of Ethernet POWERLINK protocol, and then a design of high performance process unit based on ARM and a real-time communication platform based on FPGA are presented, furthermore, an improvement strategy of clock synchronous method is proposed after analyzing the flaws of the protocol. Finally a design of gateway between Ethernet POWERLINK and TCP/IP network is presented, and the protocol is implemented in a new generation of distributed control system.The main content and innovation are as follows:1) The implementation of Ethernet POWERLINK network in a variety of platforms are discussed, mainly concentrating on the performance comparison in a Linux and FPGA environment. A design of high performance process unit based on ARM is presented, in which the driver module of general-purpose memory controller for Ethernet POWERLINK is implemented. Along with the unit, a design of real-time communication unit based on FPGA is presented too. Both parts composing the AP-PCP structure make the Ethernet POWERLINK node a perfect platform for high performance process and real-time communication.2) Two methods of clock synchronization for Ethernet POWERLINK are studied. After analysis of the cause for the clock synchronization deterioration, a method of reducing them is proposed. A Hub based on FPGA is also designed in the Ethernet POWERLINK network, which overcomes the shortage of inconsistence introduced by the packets back and forth. The study makes a significant improvement for the realization of high accuracy distributed clock synchronization network based on Ethernet POWERLINK.3) The cross communication function in Ethernet POWERLINK is studied and implemented. Also a design of gateway between Ethernet POWERLINK and TCP/IP network is presented, which solves the conflict between real-time and non-real-time data. Furthermore, the structure and characteristics of a new generation of distributed control system are introduced, in which the Ethernet POWERLINK protocol runs. |