工业实时以太网Ethernet POWERLINK机制研究

Mechanism Research on Ethernet POWERLINK of Industrial Real-Time Ethernet

针对工业控制中使用的现场总线彼此互不兼容、不易扩展的问题,提出了工业实时以太网Ethernet POWERLINK(EPL)协议的解决方案。以EPL为基础,设计并实现了三轴电机通信控制原型应用协议方案,验证了其通信机制以及实时性能。首先,在深入分析EPL协议体系架构及其通信规范的基础上,通过周期通信中主从节点状态机状态变化过程的介绍,重点研究了其对象控制及基于事件驱动的实时通信机制。进而,基于openPOWERLINK、现场可编程门阵列(FPGA)平台和运行具有实时补丁的Linux系统的计算机,设计了面向新型网络化控制系统的三轴电机运动控制应用协议,形成原型控制系统。最后,使用Wireshark工具对EPL通信过程进行实时抓包。通过对数据包的分析,验证了管理节点(MN)通过网络通信管理(NMT)状态机引导受控节点(CN)的启动过程。试验结果表明,EPL具有良好的通信性能,能够满足工业控制需求。

To solve the problem that fieldbuses used in industrial control are not compatible with each other and not easy to be expanded,a solution of industrial real-time Ethernet EPL(Ethernet Powerlink)protocol was proposed.A prototype application protocol of three-axis motor communication control was designed and implemented based on EPL,and its communication mechanism and real-time performance were verified.Firstly,based on in-depth analysis of EPL protocol architecture and its communication specifications and introduction of state transition in state machines of master-slave node in periodic communication,its object control and real time event-driven communication mechanism were studied.Furthermore,based on the openPOWERLINK,field programmable gate array(FPGA)platform and the PC running Linux system with live patching,the application protocol of three-axis motor motion control for the new networked control system was designed to form a prototype control system.Finally,EPL communication packets were captured with Wireshark tools.By analyzing the packets,the startup process of managing node(MN)booting controlled node(CN)through network management(NMT)state machine was verified.The results demonstrated that EPL has good communication performance and can meet the need of industrial control.