Research And Design Of Intelligent Measuring Instrument Based On CAN Bus

This paper encircles a intelligent measuring instrument used in bottom control of theproduce field, deploys researchs about fieldbus technology, later a more influential fieldbus inpractical application—CAN bus is introduced in detail, its operational principle,the layeredstructure and the protocol content all are elaborated. After the elaboration based on the theorylevel, combining the research content, the design and implementation of the intelligentmeasuring instrument is detailedly introduced, finally this paper does the analyticdemonstration about the development tendency of the control network. The detailed work is asfollows: First, fieldbus technology is studied, the reason which its application produced is discussed,on the basis of the analysis and comparison about the development and evolution of the controlsystem, the characteristic and superiority of fieldbus is elaborated, and the network module ofthe distributed control system based on fieldbus is presented, simultaneously an overallintroduction of several kinds of influential fieldbus in practical application is made. After that,the fieldbus which selected in this paper—CAN bus is studied and discussed, the operationalprinciple of CAN bus is elaborated, aiming at the performance and characteristic, its layeredstructure,protocol and data frame structure are analyzed and studied in detail. Second, on the basis of the CAN bus standard, design of the hardware and software of theintelligent measuring instrument based on CAN bus is detailedly elaborated according to theoverall structure.In the process of the development of system software, the developing modelwhich system software of intelligent instrument is programmed by assemble language in thepast is given up,the other way round, embedded high level programming language C51 isapplied to it. Furthermore, emulator S51 and emulating software WAVE6000 are consisted ofemulating environment, they are used for programming and debugging of system software. Inthe fourth chapter, two problems—electromagnetisms compatibility and system error which acton sticking point in reliable work of intelligent instrument are analyzed.The system interfere isanalysed and anti-jamming design adopted in intelligent measuring instrument according to theintruder and position of jam acted is presented. The reason of error formed is analysed, themeasures of reducing error are presented. Last, from fieldbus the development of control network is discussed, the fusion of controlnetwork and information network is its inevitable development tendency is summarized, finallythe actuality of development and research of embedded Internet is explained.