A Synchronization Method for Local Applications of EtherCAT Master-Slave in Open CNC System

A synchronization method for local applications of EtherCAT master-slave is proposed in this paper. Firstly, initial shift time is defined according to the communication structure of EtherCAT master-slave in open CNC system. Then, the initial shift time and clock rate ratio between master clock and reference clock is calculated for initialization of SYNC0 signal. After that, master’s cycle remaining time is defined for adjusting the master cycle time. Finally, reference shift time and measuring shift time is defined and calculated. The time difference of them is used as the basis for compensating the cycle remaining time. The master’s cycle time is adjusted by compensating the cycle remaining time and the synchronization of local applications of EtherCAT master-slave is realized by adjusting the master’s cycle. Experimental results showed that good synchronization effect of local applications of EtherCAT master-slave can be achieved in open CNC system.