Development And Application Of Backplane-Type EtherCAT Slave Controller

With the rapid development of Ethernet technology, as well as real-time requirement enhance in industrial field, real-time Ethernet technology is becoming an important developing direction for industrial field bus technology. Among several popular real-time Ethernet technology, EtherCAT is considered to be the fastest, and also the only one that able to reduce the costs of technical implementation. EtherCAT fieldbus technology has set a new performance standard, it has a flexible network topology and simple system configuration, as easy as fieldbus. From the perspective of theoretical research and product development, ET1200controller chip was used in exploiting the series slave station module based on EtherCAT technology.The paper first described research status of industrial Ethernet, then introduced the EtherCAT real-time Ethernet technology, including its system components, working principle, addressing modes, and EtherCAT slave controller chip. Based on in-depth study of the ET1200chip and Ebus protocol, design of EtherCAT slave controller adopted the backplane type, including a communication board EKM which regards PIC microcontroller as microprocessor; the board EKS-IO which is used for digital IO expansion, and stepping motor control board EKS-S.The hardware design included:backplane power conversion circuits and slot layout design; the EKM board, including the data link layer circuit design, physical layer circuit design based on KS8721BL and application-layer circuit design based on PIC microcontroller; the EKS-IO board design points were the configuration pins, power, crystal,IO, etc; the EKS-S board mainly explained design of communication mechanism between ET1200and PIC microcontroller, and the motor drive circuit. Software design included the preparation of XML configuration file and design of application layer driver. Finally, set up the test platform, analyze parameters among boards of EtherCAT slave controller, such as network latency, the time jitter and so on, proving realization of their communication functions.On the basis of the analysis and study of three-dimensional warehouse process, combining EtherCAT slave controller built related control system, using CoDeSys develop stepping motor control function blocks and complete the three-dimensional warehouse control software design, further verified the EtherCAT slave controller accord with EtherCAT technical specification.