The Design And Research Of EtherCAT In The Servo Control System

The industrial control network using industrial Ethernet fieldbus technology is inevitable with ambitious development prospects, however, the traditional carrier sense multiple access/collision detection mechanism(CSMA/CD) Ethernet MAC technology because of its non-predictable medium access mechanism, is unable to meet the requirements of industrial fieldbus’s performance.The EtherCAT technology has flexible topology, can be used easily and developed inexpensively, especially because of its excellent real-time and synchronization performance, apply it to the servo motion control network, could provide good network platform for the further development of the field of mechanical motion control like CNC machine tools, printing, industrial robots and so on.This article describes the basic working principle of the industrial control network and servo motion control system simply, introduces several current popular fieldbus technology.Compared with other network technologies, the article focuses on the EtherCAT real-time synchronization performance.The paper introduces the EtherCAT’s flexible network topology when EtherCAT working in the style of a master multiple slaves mode, this can be applied to the industrial control environment comfortably.Then this paper analses EtherCAT’s data frame、network addressing and communication mode,elaborates the work principle of EtherCAT.Due to the distribution clock of EtherCAT,it can provide accurate clock synchronization for all the EtherCAT network.The paper focuses on the design of a multi-axis servo motion control system based on the EtherCAT.The hardware system is the linear topology,with the master need a PC with a NIC (network interface card), the special chip ET1100is the slave hardware communication core and the DSP is the motion control microprocessor core.The paper designs a new interface of ET1100and DSP, the master software use TWinCAT to configure and develop,and the slave software needs to be designed according to the network structure. By the experimental test,the design is successful.Finally, the paper points out the article shortcomings as well as follow-up work.