Research Of Embedded Industrial Measurement And Control System Based On MODBUS Field-Bus

With the development of modern science and technology and the unceasingenhancement of production automaticity, industry control computer and One-chipComputer based on PC cannot satisfy the need of object-oriented application.By theformidable function and the the faster processing speed, the embedded microprocessorgradually becomes the mainstream in the embedded system design. Moreover, there isan operating system embedded in the microprocessor, which makes the system evenmore powerful,and makes it play an important role in every field in society.This article designs a set of embedded industry measurement and controlsystem,with the background of industrial boiler.First, the article discusses theembedded technology. The embedded microprocessors,especially the ARMseries,were introduced and compared.However,AT91RM9200,whitch is one of the chips of ARM9 series,is elaborated.Then, the design of embedded industry measurement and control system ispresents. The system takes the smallest system of the AT91RM9200 processor whichis based on ARM9 as a core, and integrates some hardware circuit, such as, the LCD,the touching screen, the pronunciation alarm, the industry ethernet, RS-485, A/D, D/A,the USB connection,the integrated I/O expansion control module and so on.In th end,the paper elaborates the communication of this system. The system isconsidered as the lower computer, and the upper computer is a PC of controlcenter.They select MODBUS protocol as the correspondence agreement.and theprotocol has the advantage of simplicity.In the aspect of hardware,according to thecharacter controller object and the situation,the system adopts RS-485 bus,whitchsuits long-distance communication.Besides,Linux system is the platform of the lowercomputer, and C language is used. The upper computer takes WindowsXP as theplatform,and uses MSComm controls of VC++ programming.The article adopts embedded technology, realizes the control of industrial boilersand devices resembled boiler.It can control the parameters of temperature,pressure,water level etc.Moreover, the system has the function of LCDshow, automatic alarm,communication,collect mass input signals and output masssignals. This system has the ablity of real time,stability, secutity, credibility andexpandability.