EtherCAT网络控制中从站间传输延时研究

Research on transmission delay between slaves of EtherCAT network control

网络控制系统在机电一体化制造领域起到关键性作用.在网络控制中,预先计算从站间的传输延时是实现各从站时钟同步的基础.EtherCAT从站物理层接口有MII(media independent interface)和EBUS两种类型,按照这2种类型,分数据帧传递的往返两个方向,分析了从站间的传输延时.针对实验系统,对系统上具体从站间的传输延时作了理论计算及实验测试.通过对比理论计算值和实验测试值,验证了理论分析的正确性,为以后组建实际机电一体化系统、根据实际需要搭配从站、减少从站间的传输延时和提高控制系统的实时性提供了理论依据.

Network control system is a key role for mechanical and electrical integration manufac-ture .Pre-calculation of the transmission delay between slaves is the basis to realize the clock syn-chronization of slaves in network control system .There are two types of physical layer interface on EtherCAT slave ,MII （media independent interface） and EBUS .According to the type and the transmission direction of data frame ,the transmission delay between slaves was analyzed .Aimed at the experiment system ,the transmission delay between slaves was calculated and measured . By comparing the theoretical calculation value and the experimental test value ,the correctness of the theoretical analysis was verified .Theoretical basis was provided in building actual system for matching the slaves according to the actual need ,reducing the transmission delay between slaves and enhancing the real time ability of control system .