Design Of Communication System Based On PROFIBUS-DP

Profibus is an international standard for fieldbus which is open and independed on equipment manufacturer,this protocol can be widely used in manufactur automation , flow industry automation , construction ,transportation and power transmission field.Profibus-DP is an communication protocol with high speed and low cost,mainly used in equipment level control system and decentralized I/O communcattion.Presently the application and exploitation of DP fieldbus technology is widely used,but the exploitation of intellective equipment based on DP is slow,and most of which is limited in intellective instrument of slave station,the master station of Profibus-DP has not been successfully designed domesticly.The slave station have to connect with foreign master station like Siemens . This situation influence the development of DP technology,and that make the advantage of the DP technology can't be fully used.Based on the study of Profibus-DP theory and the working mechanism of the slaver,this thesis not only introduces the design method of software of the master station,but also builds the testing platform with the simulation of slave station and master station,which can be in good communication.The software design consists of two parts.One is the cycle communication function of the master station joining in data exchanging with slave station,including detection,parameterization,configuration and redetection of master station.The other one is communication function of master station with other master station in fieldbus.Which is the token exchanging,including generation of token loop,how to join the master station to the bus,how to delete failure master station,when to add new master station to bus and how to overcome the interference to restore the token exchanging. This thesis configurates the hardware and software of the master and slaver by using the congfiguration software of STEP7 , WINCC and SIMATIC NET.The experiment on the communication system is carried out by the fieldbus control system of master station and slave station.