Design And Implementation Of Ether CAT Master For CNC System

With the rapid development of all the technologies in the field of industrial control,the real time industrial Ethernet has already been a key technology which is necessary for further development of the CNC system.In many real time industrial Ethernet technologies,EtherCAT has received attention from more and more enterprise because of its high response speed,high transmission efficiency,good synchronization performance and flexible topology.In this paper,we design and implement an embedded EtherCAT master station based on ARM and FPGA.After analyzing the basic principle of EtherCAT and the hardware structure of the master station,we research the data link layer and the application layer of EtherCAT protocol deeply.On the basis of these,we design the software solution on ARM,distributed clock and the PCI driver program.In the paper we discuss the basic functions implemented in ARM such as how the master station control the application layer EtherCAT state machine of slave stations,how the master station and the slave stations communicate with aperiodic mailbox data communication,and error monitoring function.On the analysis of synchronization timing relationships between master and slave stations,we design and implement the distributed clock solution.At last,we use On Time RTOS-32 to implement the PCI driver of the master station with PCI BIOS.Based on KEB and IO test board,we set up a test platform and make a test program to test the basic functions of EtherCAT and the synchronization performance of the master station.The shows that the master station has implemented the basic functions of EtherCAT and has a good synchronization performance.At present,the master Station has been put into use,and it can meet the requirement of real time performance,reliability,and response speed of CNC system.