【正文】 “一線”是指其骨架計算機(jī)網(wǎng)絡(luò)，“三點(diǎn)”則是指連接在網(wǎng)絡(luò)上的三種不同類型的節(jié)點(diǎn) :面向被控過程現(xiàn)場的現(xiàn)場 I/O控制站；面向操作人員的操作員站；面向 DCS監(jiān)督管理人員的工程師站。 DCS的基本組成部分 系統(tǒng)的邏輯結(jié)構(gòu)需要由物理結(jié)構(gòu)實(shí)現(xiàn)。 DCS是由計算機(jī)技術(shù)、信號處理技術(shù)、測量控制技術(shù)、通信網(wǎng)絡(luò)技術(shù)、 CRT技術(shù)、圖形顯示技術(shù)及人機(jī)接口技術(shù)相互滲透發(fā)展而產(chǎn)生的。s procedure, the operation results is stored in in relevant device registers again. 3, Export the stage of breaking After the procedure finishes carrying out, convey the state of videoing the register of the ponent of all output relays to the corresponding output while latching the circuit, through isolating the circuit , to drive the power amplification circuit , make the output end son export the control signal to the external world, form the actual output of PLC, drive the corresponding peripheral hardware. The structure PLC PLC is a real dedicated to the control of the puter industry, its hardware is basically the same microputer: 1, Central processing unit (CPU) Central processing unit (CPU) central processing unit (CPU) is the control center PLC. It PLC system in accordance with the procedures for the functions entrusted to receive and store programming from the user input devices and data。s procedure sentence by sentence, meet and jump the order of rotating, according to shifting the trend that the condition decides the procedure. User39。 Discern the unit of expanding . Then enter circulation and scan the working course , this working course is divided into the inside and dealt with , sets up service of ports , procedure and inputs and deals with outside, the procedure carries out, the procedure exports several stages. The whole course is scanned the necessary time of once to call and scan cycle . Deal with stage insidly: CPU should be restored to the thro ne watchdog timer , hardware to check , user39。s procedure , CPU scans the laddershaped picture one by one right, the execution of the procedure is carried on according to the priority order that the sentence is arranged , it is a kind of serial working way. Initialize at first after the electricity on PLC: Auxiliary , special auxiliary , auxiliary regional zero clearing of memory relay of I/0 , inside 。t directly control outside load , can only make middle result to use while supporting CPU . PLC scans the incident according to circulation, carry out along the priority order of the laddershaped picture, result of the cycle stay in state of outputting temporarily in the person who deposit so value ordered to output can regard as terms use among the procedure in user in the same scanning. Sentence predicative speech , is similar to the assembler language . Logic functional diagram language, continue to use semiconductor logic block diagram is it express to e, one operation frame generally show one function on the left draw introduction , on the right paint and export. 4 Use the programe of STEP7 Establishing a project structure, the project is just like a file, all data exist among them with the structure of dividing floor, you can use at any time. After establishing a project, all other tasks are carried out under this project. Configuration one station, configuration one station to appoint you want programmable controller that use, such as S7300 , S7400 ,etc.. Configuration hardware, configuration hardware appoint control scheme of you want template that use and with what kind of address visit these template among the procedure in user among the form in configuration, the address needn39。s procedure . The systematic procedure includes controlling procedure , piler , diagnostic program ,etc., used for manage the whole machine , translate the procedure language into a machine languaging mainly, diagnose the mechanical disorder. Systems soft ware offer by PLC producer and solidification among EPROM, can39。s terminal station of the type and use more and more extensive at present, it is popularized very much that the puter (operation configuration software ) makes manmachine interface. The munication of PLC is worked May collect , convey producing and manage the data promptly and efficiently while relying on the advanced industrial work technology. So, the importance of the work in the automatic system integration project is more and more remarkable, even someone proposes the view statement that the work is the controller . PLC have function that munication work, it make PLC and between the PLC , PLC with go to location puter and other intellectual equipment can exchange information , form a unified whole, realize dispersing centralized control. Most PLC has RS232 interface, puts and supports the interface of each munication protocol when there is some. Communication of PLC adopt through some data munication , PROFIBUS or industry39。s procedure storing device , produce the corresponding control signal according to the task that the order stipulates after analysing, go to mand relevant control circuits . CPU and realizes by arithmetic unit , controller , register mainly the data , control and state bus of the connection among them are formed , unit CPU still includes peripheral chip , interface of the bus and relevant circuit. The memory is used for storing the procedure and data mainly, is indispensable position unit PLC. In user39。s address. Various manufacturers of DCS on the treatment of some differences in puting algorithms, so not the same name. If the internal DCS Instrument said the algorithms, but its essence is a process, essentially the same. In the use of these function blocks, it should indicate that the function block input and output relationship between the operation, there puting needs many parameters. According to the controlled object in the user to determine the control strategy formation control program, select the function block library with the required control function blocks, clear the connection between the relationship between functional