Design And Study On Communication Adapter Of CAN And Modbus

With the rapid development of smart grid and technology of intelligent apparatus,more and more attention is paid to the field-bus technology. As a kind of controlnetwork that has superior performance, good reliability, complete structure of functionand flexible application, CAN bus has been widely used in all kinds of automationcommunication field. The physical layer and the link layer of Modbus protocol arerealized by the EIA485which is serial links bus, and it is usually used in switchequipment and instrument equipment in distribution network.In the smart grid, serial communication bus, which using EIA485as physicallayer and Modbus as application layer, is adopted in the intelligent devices whichhave the function of communication. But as heterogeneous networks，CAN andModbus may both exist and be interconnected in the environment of increasinglycomplex network. But due to the incompatible between Modbus and CAN, Modbusdevices can not be connected to the CAN bus network.In this paper, the CAN bus network and the Modbus protocol network werestudied, and a kind of communication transformation scheme was designed to realizethe interconnection of two kinds network, which use the specific data transmissionand the encoding/decoding rules of packet fragmentation and reassembly. The datalink of CAN-bus was studied by analyzing the data delay characteristics to ensure thatthe adapter which is used the communication scheme works properly.On this basis, the communication adapter was experimented on simulationcommunication test and industrial field test, and then the function index was analyzedwith that test data.