The Design And Realization Of EtherCAT Master

Industrial bus technology is the field bus based on Ethernet technology. Nowadays, with the development of the area of Industrial control, the technology of Real-time industrial bus has become an important development direction of field bus technology. In addition to the advantages of real time industrial bus, EtherCAT(Ethernet control automation technology) also have the advantages of low cost, simple topology and flexible topology. Ether CAT has become a research hotspot in the field of industrial control.Due to the functions defined by EtherCAT, EtheCAT protocol is divided into three layers which are application layer、data link layer and physical layer. Meanwhile, there are some sub-protocol in EtherCAT physical layer. EtherCAT uses master-slave mode to access control. In the network of EtherCAT, the core of communction is master. EtherCAT master use basic communication mode and mailbox mode:we use basic communication to access information of slaves from eeprom, then matser will use mailbox mode to configure and interview slaves. There are four basic states in slave, EtherCAT clearly defined all the operations doing by master in every state. Matser need to do the correct operations when slave in the state, and make slave change the state. When the slave is in operatinal state, master need to exchange periodic data to inquire or control the slave.In this paper, the aim is to design a EtherCAT master software. Comparing the basic solution in Linux and Windows, because of the cost and difficulty, we choose Linux system to ralize EtherCAT master softwore. In order to realize all the functions, on the basis of the research of EtherCAT, this paper divides EtherCAT software into six functional moudules, which are management control module, configuration module, subprotocol module, slaves’ information module, core communication module and network card driver module. In the paper, all the modules’ realizations are explained in detail. All the functions will be tested. Of course, the time between the communction is trying to be tested.