The Research Of Wireless Fieldbus

With the control systems becoming decentralized, networked and intelligent, thetechnology of fieldbus has becoming the research focus all over the world.But facing the measurement and control of some mobile, rotated or the dangerousobjects in the production field of industry environment, wired physical medium ishard to join;with the development of industrial ethernet, multilevel network need tocombine the ethernet and fieldbus;the cost of industrial wire layout is high. It is thebest scheme to slove the problem by applying the wireless ethernet technical to thefieldbus.This paper is to research CAN bus. On the foundation of analysing CAN bus andIEEE 802.11x, the research apply WLAN IEEE 802.11b to the industrial CANfieldbus as extended wireless CAN network. By considering existing technicalcompatible problem, easy realization problem and the requirement of the otherrequirements, the research determine the technical goals of wireless CAN network.This paper designes the network configuration of wireless CAN network -Virtual Ring Extended( VRE), wired nodes and wireless nodes may run in a sameCAN network;analyses how to guarantee high performance and the high speed ofphysical layer using DSSS technology;designs the special AP node -AP-IWU thatrealizes the smooth bridge of wired/wireless net;realizes the combination of the CANand IEEE 802.11b in apply layer;designs Finite State Machine(FSM) of the masternode and the slave node, verifies the accessibility of FSMs;at last, the real-time of thenetwork system is discussed. Aiming at the characteristic of wireless channel, theresearch puts forward the algorithm of scheduling data and determines networktransmission delay of the period data and Time-critical data in wireless CAN.