Research Of MODBUS-PROFIBUS Communication Adapter Based On SPC3

Fieldbus technology is a complex of computer technology, network technology,automatic control technology, etc. It constitutes an intelligent, bi-directional interconnection,multicontact, full distributed and all digital communication and control system.Fieldbusinclude a variety of bus standards,profibus (Process Field Bus) is one of competing researchand application standard in a variety of field bus standard for its significant advantages.At present, Profibus-DP has been enough mature in foreign countries, and the relatedproducts account for a large proportion in the market,while in China, the research ofProfibus-DP technology is still in the stage of stable development. With the rapiddevelopment of Profibus technology, more and more communication equipments shouldhave function to communicate with Profibus bus, while the domestic market,for itsequipped with the Modbus interface only, most of the communication equipments can notachieve direct communicate with the Profibus bus.In this case, it is not economical andunrealistic to change all these communicate equipments to communicate equipments withProfibus interface. To solve this problem,the design plan of Modbus-Profibuscommunication adapter is proposed based on the study of Profibus-DP technology, and thespecific implementation steps is detailed described.Firstly, an brief introduction of the development of the fieldbus and fieldbus protocolconversion is given.As well as, the application and development of the Modbus-Profibuscommunication adapter is analyzed.Secondly, the composition of Profibus and Modbus andthe structure of each bus protocol is detailed instructed.On the above basis, the specificimplementation plan of the Modbus-Profibus communication adapter is proposed, thespecific implementation process of the hardware and software design is detaileddescribed.At the same time, the communication adapter is tested by two plan under thebuild test platform. It is verified that the designed Modbus-Profibus communication adaptercan operate stable and reliable.Through designed Modbus-Profibus communication adapter in this paper,communications equipments with standard RS485interface based on Modbus protocol canbe simple, easy accessed to Profibus bus system, and achieve the communication of thosedevices and Profibus bus. Through Profibus bus user can monitor and control it in real time,fully in line with market demand, has some practical value.