Research And Development On Real Time Ethernet Communication Based On NetX

With the development of the microelectronic and power electronic technology, motion control system has developed from analog control to digital control, its performance is improved continuously; it has been applied widely in industrial automation equipment. Based on motion control system of real-time ethernet for its high reliability, rapidity and stability, real-time ethernet become the development trend of motion control system, German Beckhoff proposed EtheCAT real-time ethernet technology. This technology improved real-time performance of motion control system; it has characteristics with flexible topology, superior network performance, lower construction cost. It is suitable in the field of motion control. At present, the real-time ethernet motion control has attracted the developer's attention. This article in view of theoretical study and product development, utilizing comX based on netX chips and Atmega128 microcontroller developed EtherCAT real-time ethernet slave station module comEIO.This paper firstly studyed on common real-time ethernet communication protocol, by contrast their communication principles and characteristics, select EtherCAT real-time ethernet, analyzed EtherCAT principle and technical characteristics on emphasis. Secondly, combination with function of EtherCAT comEIO module and requirement of real-time ethernet communication, based on further study of netX chip, comX based on netX chip and Atmega128 microcontroller, completed main control circuit composed of Atmega128 microcontroller and Altera's CPLD, comX and MCU interface circuit, power circuit, input and output circuits and other peripheral interface circuit. Application programed by Atmega128 microcontroller completed communication operation with comX. After making comX power, loading EtherCAT real-time ethernet firmware, microcontroller send the warm start parameters to comX, then realize comEIO EtherCAT real-time ethernet slave station module function. Finally, using Beckhoff's TwinCAT software as soft master station, comEIO, NXIO and cifX as slave station, putting up EtherCAT real-time ethernet master and slave station control system test platform, utilizing real-time ethernet analyzer netANALYZER, grasping EtherCAT real-time ethernet packet, combined with network packet analysis tool Wireshark to analyze data acquisition, can analyze real-time ethernet network delay and jitter and other data from the EtherCAT packet, and analyze some superior performance of EtherCAT real-time ethernet devices. Analyze the performance of comEIO fully consistent with the cifX from data, can complete communication function of data, and then prove comEIO slave station module is fully satisfied to communication requirements of EtherCAT real-time ethernet.