The Design And Realization Of EtherCAT Master

With the development of industrial automation and intelligent factory,more and more new requirements are needed,especially on the bus system.Traditional industrial field bus is slow,complex wiring,poor compatibility and with many other problems,it is very hard to solve all those problems through upgrading.In this context,the German company Beckhoff released EtherCAT.It has a simple connection,high speed,high throughput,economical and reliable,and many other advantages.The current domestic and international development of the main station are generally from the Beckhoff company to buy source code,in the Beckhoff certified hardware platform for secondary development,so that the high cost of hardware and limited by intellectual property rights.This article implements the EtherCAT master function on the board of the motion controller,and from the hardware platform to the software development is based on the industry standard of self-study,thus greatly reducing the cost of purchasing the source.At the hardware level,this paper explains the selection,design and hardware implementation of the hardware chip in detail according to the requirements of the EtherCAT master function.In accordance with the modular thinking,respectively,the overall design of each module and circuit implementation.Specifically,this paper chooses ADI's BF533 as the core of the hardware,and then builds the external memory module according to the EBIU memory controller of BF533.The clock circuit module is built around the PLL clock control,and the communication circuit is realized according to the demand of EtherCAT network communication.To ensure the normal operation of the above module circuit design of the power module and peripheral expansion module.At the software level,this paper introduces the basic principle of EtherCAT from the aspects of hierarchical structure,frame format,addressing mode and running principle.And then from the five basic functional modules,to achieve the EtherCAT master data link layer,physical layer and application layer sub-protocol.The communication module is connected with the physical layer and the data link layer,which realizes the identification and calling of the hardware network card.The communication primitive module and the core function module realize the basic communication function,which belongs to the data link layer;the CANopen module realizes the COE sub-protocol,which is the same as the slave configuration module.Finally,on the basis of implementing the five modules,the overall work flow and state transition of the master station are described accordingly.Taking into account the reliability and maintenance requirements of the host program operation,this paper uses the uClinux system on the hardware controller and then runs the master program under the system.UClinux part of the system kernel and U-Boot related to the cut,modify and related registers and parameter configuration.Finally,this paper tests the hardware platform and uClinux system.Under the premise of ensuring the hardware and system normal,the master software is run under uClinux,and the control of the slave state transition is realized.