Research On DeviceNet Fieldbus Network Communication Technology

Fieldbus is a kind of network for intelligent device of work field developed in the 80~90 of 20 century. It has been widely used in the fields of process automation,manufacture automation as well as building automation. As a new technology, The Fieldbus integrated computer technology, communication technology and control technology, and so, it has been the focus of the automation development of the world. It is necessary to research and development our own Fieldbus products inorder to cooperate with the prospect of our country's economy.This paper selects one of the low voltage apparatus on which to implement the DeviceNet Specification. The I/O module will be selected as the low voltage apparatus. The main intention is to research the DeviceNet specification and the development of the DeviceNet products via this work, and hope this work can do something for the development of the Fieldbus products. The main works of this paper are as follows:First, this paper describes the characters and the network frame of the Fieldbus, and keeps close watch on the new developments of the Fieldbus. The background and characteristics of several important Fieldbus are analyzed and compared, and their competent fields are also mentioned.And then, the DeviceNet specification is studied and its frame.is discussed carefully. The DeviceNet specification is a set of perfectly and logically protocol, and can be used for kinds of different fields. This paper researches its implementation on low voltage apparatus and realizes hardware and software design for the DeviceNet interface..The P87C591 microcontroller with CAN controller chip was selected to realize the DeviceNet specification, and the PCA82C250 CAN transceiver wasused for connecting to the DeviceNet bus.This paper designs the hardware circuit and completed the hardware manufacture of the slave node. The slave node combined with the IPC-I320 master board made by IXXAT company make up of a typical master/slave network. An easy build and reliable hardware solution is available in this paper.The software of the DeviceNet interface was compiled by C51,including the duplicate MAC ID detect, the predefined master/slave connection set, the state transition diagram and so on. This paper realizes the objects of the slave according to the DeviceNet specification, and emulates by E6000/T emulator. The results shown that the slave can communicate with the master as we have expected. Finally, the paper gives an abstract description for the development of the DeviceNet filedbus products. The trend of the development and research hot spot of Fieldbus are put forwarded. In order to prompt the development of DeviceNet products in our nation, the paper provides author's opinions on both application and implementation of the DeviceNet Fieldbus on low voltage apparatus.