Research Of Integrated Slave Node Based On PROFIBUS-DP And MODBUS

PROFIBUS-DP is a kind of international fieldbus that oriented to factory automation and process automation. It’s a open digital communication system that widely used and is fit for all kinds of communication task that need fast, time limited, and high reliability. MODBUS communication protocol is the earliest that used on electronic control unit. By modbus communication protocol, the communication between controllers and controllers communicate with other devices by network can be realized. So far, there are kinds of products related to the fieldbus above, among them,the slave station used to connect the master station and external device is key technology now researched. At present, the research about multiple fieldbus intergration is not much, the research of a device about integrational slave station based on PROFIBUS-DP and MODBUS is showed in this paper. Fast switch between the two slave station in this module is realized. The main part is showed below:1. First of all, the development situation at home and abroad and the research contents are introduced in this paper, then the architecture, communication theory and data structure of the two fieldbus are analysised.2. After analysis the common technology of the two fieldbus, how to integrate two kinds of fieldbus in one MCU is deeply researched and realized. The switch between the two slave station is solved and the general planning is designed finally. The software and hardware designing is solved based on the above. The PROFIBUS-DP slave station is mainly made up by MCU, SPC3and the RS485driver circuit and the MODBUS slave station in made up by MCU and the RS485driver circuit, at last the working principle of the hardware circuit is explained. As to the software designing, the software of the two fieldbus are programmed separately and combined into a integrated code at last.3. According to the technology about slave station test and the functional requirements of the two slave stations, the test scheme is deeply analysised and demonstrated. The experiment were done after the two test platforms were constructed separately. The experimental result was analysised deeply and the design scheme showed in the paper was confirmed right, and the switch of the two fieldbus is realized.