【正文】 eposit register that stipulate , meanwhile , diagnose power and working state and grammar mistake ,etc. , programming of course of circuit inside the PLC. Enter after running, read the order one by one from user39。 3, the realtime trend shows: With curve say e out change recently, producting process of data, so that the operator understands its development and change to some extent, and can help to analyse the running situation of the production process .which Can generally show the trend curves of 48 data in the same system of coordinates , so can pare with all relevant data ,to make the analysis on onthespot situation very more clearly. The engineer stands It is disposed to DCS offline that the engineer stands, configuration and work node supervised , controlled , maintained online. Its main function is to finish the systematic configuration , dispose the work, and monitor the each nodal running situation when real when the line is operated, make system engineer can stand in time adjusting system disposing and some settlement of systematic parameter through engineer, to make the system in the best working state at any time. Systematic work It is all some isolated nodes that onthespot I/O is controlled and stands , stands at operator39。s station The operator of DCS deals with all functions of manmachine interface (MMIMan Machine Interface ) related to operating and operating at station, embody in and offer the manmachine interface for operating attendants mainly, enable operators to understand onthespot operation state , to present value of various kinds of operation parameters , and have unusual situations to take place etc. In time through operator39。s engineer standing. I/O controls the station live An onthespot I / O is controlled and stood to finish dealing with and realizing the work node of digital control DDC (Direct Digital Control ) directly to onthespot I/O of course, there are three main functions: 1, which carried on digitization of various kinds of onthespot course amount (such as the flow , pressure ), and the quantity after digitizing is stored in the memory , form one keep the same with onthespot course amountly, can oneone is it video in real time according to actual running situation with newer onthespot course quantity to change in real timing。 Facing the attenbant39。s operator39。 2, the realtime data gathering our station are sent to operator39。s station, and can control and regulate the craft course through the input equipment , so as to ensure the security of the production process , reliable , highefficient , high quality. It is colored CRT that operator39。s station and engineer, to finish one39。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 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 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 。s procedure sentence by sentence, meet and jump the order of rotating, according to shifting the trend that the condition decides the procedure. User39。 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?！耙痪€”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)。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 a mplification 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。 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 throne watchdog timer , hardware to check , user39。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 pi