A network based motion control system, in which the NC interpolation node and the servo control nodes were connected by IEEE 1394, was analyzed and tested, and it is found there exists problem in multi-node synchronization. In order to solve the problem, this paper proposed a protocol for the field-bus and a synchronization mechanism based on CNC-RTX clock timing. Real-time communication among CNC nodes and four sub-nodes was realized, and synchronization errors among CNC nodes and sub-nodes caused by clock floating, network induced delay, and different timing mechanism were avoided as well. Experimental results show that the application layer protocol and the synchronization mechanism can realize high performance in communication with less synchronization errors.

针对由CNC实现实时插补、由伺服节点完成位置闭环控制的数控平台，分析了基于IEEE1394的网络化运动控制系统的节点不同步问题，并进行了多节点同步测试。在该平台上，制定了总线通信协议，提出了基于CNC-RTX定时时钟的总线同步机制。实现了CNC根节点与4个分支节点的实时通信与控制，克服了多轴控制中各分支节点由于时钟漂移和网络时延以及上下位机采用不同的定时机制所导致的同步误差。实验表明，通信协议与同步机制可以满足数控通信需求，实现各节点的高度同步。

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