dcs原理与plc基础外文翻译(编辑修改稿)

dcs原理与plc基础外文翻译(编辑修改稿)内容摘要：

ide from structure, PLC is divided into a regular type and sectional (module type ) two kinds Regular type PLC including CPU board , I/O board , showing the panel , memory lump , power ,etc., these elements are made up into a whole not detachable . Module type PLC includes CPU module , I/O module , memory , power module , the baseplate or the framework, the module can be made up and disposes according to certain rule. Composition of CPU CPU is a core of PLC, functions as nerve center, each set of PLC has one CPU at least, it receives and stores user39。 s procedure and data according to the function that the systematic procedure of PLC gives, gathered and input the state or data that the device sends here live by means of scanning, deposit 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 fro m user39。 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 view , it is unnecessary to analyse the inside circuit of CPU in detail, but there should be enough understanding to the working mechnism of every part. The controller of CPU controls CPU and works, is read the order, explained the order and executed instruction by it. But working rhythm is controlled from the signal of shaking . The arithmetic unit is used for carrying on figures or logic operation, work under the circumstances that the controller is manded. The register is participated in operation, store the middle result of operation, it works under the circumstances that the controller is manded too. CPU speed and capacity of memory are important parameters of PLC, they are determining the working speed of PLC, IO quantity and capacity of software,etc., so is exercising restraint in controlling the scale . I/O module The interface of PLC and electric return circuit , finished through inputting the output (I/O ). I/O circuit of I/O module integrated PLC, it is input temporarily the storing device reflects the state of the input signal, export and click and reflect that exports the state of the latch. Input module vary electric signal digital signal enter PLC system , output module to be opposite. I/O is divided and imported (DI) for the switch amount, the switch amount is exported (DO), analog quantity is input (AI), analog quantity is exported (AO),etc. the module . Commonly used I/O is classified as follows: Switch amount: Divide according to the voltage level, there are 220VAC , 110VAC , 24VDC , divide according to the way of isolating, there are relays that are isolated and isolated with the transistor. Analog quantity: Divide according to the signal type, the electric current type (420mA , 020mA ) , voltage having type (010V, 05V, 1010V),etc.,it is according to precision fen, there is 12bit , 14bit, 16bit ,etc.. Besides abovementioned IO in mon use , there is special IO module , for instance such module as thermal resistance , electric thermocouple , pulse ,etc.. Is it confirm module specification and quantity to count according to I/O, I/O module but many and very little, its great number receive CPU can basic ability of disposition of management most, namely is counted the restriction by the biggest baseplate or the framework trough . Power module PLC power is used for offering the working power for integrated circuit of every module of PLC. Meanwhile, some still offer the working power of 24V for inputting the circuit. The type is as follows, that the power imports Exchange the power (220VAC or 110VAC ), direct current power (a monly used one is 24VDC). The baseplate or the framework Most module type PLCs use the baseplate or the framework, its function is: Have electrically, realize the connection among every module , enable CPU to visit all module on the baseplate, on machinery , realize the connection among every module , make every module form a whole . Other equipment of PLC system 1. programming equipment: The programmable device is that PLC develops and adopts, monitors operating, checks and maintains the indispensable device, used in programming , do some settlement , working state controlling the system that PLC and PLC control to the system, but it does not participate in directly and control and run live . The small programmable device PLC generally has holding type programmable device, generally the puter (operates the programming software ) makes programmable device at present. That is to say we system go to location plane. Manmachine interface: The simplest manmachine interface is indicator lamp and button, the liquid crystal reject (or the touchsensitive screen ) an organic whole type operator39。 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 intelle。