Design And Implementation Of MVB Network Card Software For PIC Device

Compared with the other transportation modes, urban rail traffic has the characteristics of large capacity, high efficiency, low energy consumption and intensification. With the development of society, urban rail transit is developing forward to automation and high-speed. As the rapid development of rail transit, there are higher requirements for the train communication network, intelligence and networking has become an inevitable requirement for train communication network.MVB is the recommended network of TCN standard. More and more locomotives require vehicle equipment to transmit the state, data and control signal via MVB. Many of the early vehicles also require using MVB to build a more perfect train communication network. In the early locomotive, PLC controller is widely used, while MVB network card must be used when vehicle equipment wants to communicate with the MVB bus. At present, MVB card requires host controller supporting the C programming language, but the traditional PLC device does not have this ability. In general, the external interface of the PLC controller only supports some simple communication based on standard protocols, such as Modbus, CAN bus, etc.. Therefore, the transformation of the original PLC controller-based system can not extend the MVB interface, and for the manufacturers that are only acquainted with the PLC industrial programming, there are some difficulties when using the C Language programming.This thesis designed an MVB network card which is controlled by PLC equipment via Modbus protocol. Firstly, the status of train communication network is analyzed, and MVB and Modbus protocol are studied in depth. Then overall design is given on the basis of summing up the PLC equipment application characteristics. According to the characteristics of the communication of PLC equipment, interface between PLC device and MVB card is designed, and the rules which PLC equipment control the MVB network card are given, the functions of Modbus master are implemented and the software design is introduced in detail. The MVB network card has been tested, and the results show PLC equipment can operation the MVB card through standard Modbus protocol, support standard program based on IEC61131and communicate with the MVB devices within the network, the designed MVB network device properly meets the application requirements of the PLC equipment.