材料自動分揀系統(tǒng)的PLC設計
材料自動分揀系統(tǒng)的PLC設計,材料,自動,分揀,系統(tǒng),PLC,設計
外文資料翻譯
PLC foundation
1.1Development course of PLC
In the course of industrial production, a large number of switch amount orders are controlled, it carries on order movements according to the logic condition , and carry on the control that the chain protected movements according to the logic relation, and the data of a large number of dispersed quantity are gathered . Traditionally, these functions were realized through the pneumatic or electric control system. The Company put forward and replaced the demand which continued the electric control device in U.S.A. GM in 1968 (General Motors ), in second year, American digital company develops the control device based on integrated circuit and electronic technology, adopt means of procedure apply electric to control for the first time, this it is first generation that can programme the controller , call Programmable Controller.
After the personal computer develops, for being convenient, in order to reflect the function characteristic of the programmable controller too, can programme controller name Programmable Logic Controller (PLC).
The eighties of last century is to the middle period of the 1990s, it was PLC the period with the fastest developing speed, the annual growth kept 300%. This period, PLC is improved by a large margin in power to dispose of analog quantity , digital operation ability , man-machine interface ability and network ability , PLC enters the course controlled field gradually, has replaced and in DCS system ruling position on the course controlled field in some is used.
PLC have commonability to be strong easy to use meeting surface wide , dependability high , anti-interference ability strong , programming characteristicking such as being simple. The position in PLC is controlled in the industrial automation especially the order is controlled, in foreseeable future, can replace.
1.2 Composition of PLC
Divide 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.
1.3 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 user'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 from user's procedure storing device , produce the corresponding control signal according to the task that the order stipulates after analysing, go to command 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 composition unit PLC.
In user'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 commanded. The register is participated in operation, store the middle result of operation, it works under the circumstances that the controller is commanded 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 .
1.4 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 (4-20mA , 0-20mA ) , voltage having type (0-10V, 0-5V,- 10-10V),etc.,it is according to precision fen, there is 12bit , 14bit, 16bit ,etc..
Besides above-mentioned IO in common 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 .
1.5 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 commonly used one is 24VDC).
1.6 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 .
1.7 Other equipment of PLC system
1.7.A 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 computer (operates the programming software ) makes programmable device at present. That is to say we system go to location plane.
1.7.B Man-machine interface: The simplest man-machine interface is indicator lamp and button, the liquid crystal reject (or the touch-sensitive screen ) an organic whole type operator's terminal station of the type and use more and more extensive at present, it is popularized very much that the computer (operation configuration software ) makes man-machine interface.
1.8 The communication of PLC is networked
May collect , convey producing and manage the data promptly and efficiently while relying on the advanced industrial network technology. So, the importance of the network in the automatic system integration project is more and more remarkable, even someone proposes the view statement that " the network is the controller " .
PLC have function that communication network, it make PLC and between the PLC , PLC with go to location computer and other intellectual equipment can exchange information , form a unified whole, realize dispersing centralized control. Most PLC has RS-232 interface, puts and supports the interface of each communication protocol when there is some. Communication of PLC adopt through some data communication , PROFIBUS or industry's Ethernet of interface (MPI ) network more mainly now.
2. Design basic principle of PLC control system
2.1 Meet the control request which is accused of the target maximumly.
2.2 On the premise of meeting control request , is it make control system simple , economy , use and maintain convenient to make every effort.
2.3 Guarantee the control system is safe and reliable.
2.4 Consider the development of production and improvement of the craft should leave the surplus properly while choosing PLC capacity.
3. PLC software system and daily programming language
3.1 PLC software system is made up of systematic procedure and user's procedure . The systematic procedure includes controlling procedure , compiler , 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, can't direct access interfere from already. User procedure whether user according to on-the-spot control request, used for realizing various kinds of control with procedure application program (the logic control) that language make of PLC. STEP7 is used for SIMATIC programmable logic controller configuration and standard software package of programming, that is to say user procedure, we use STEP7 is it carry on hardware configuration and logic procedure work out to come, and the logic procedure carries out the monitoring online of the result
3.2 Programming language that PLC offers
3.2.1The ladder-shaped picture language of standard language is a kind of most frequently used languages of ours too, it has the following characteristic
3.2.1.1 It is a kind of figure language, term of continuing to use relay contact , coil that the tradition controls in pictures , contacting etc. and some graphical symbols are formed , the vertical line of left and right sides is called and controlled the bus bar.
3.2.1.2 The contact (contact ) only often opens and often closes in the ladder-shaped picture, the contact can be that can be a state of contact or inside register , counter of the relay ,etc. within PLC too that PLC input and click the switch connected .
3.2.1.3 Contact of ladder-shaped picture can wanton bunch, connect in parallel, the coil can only be connected in parallel and can contact .
3.2.1.4 Inside relay , counter , register ,etc. can't directly control outside load , can only make middle result to use while supporting CPU .
3.2.1.5 PLC scans the incident according to circulation, carry out along the priority order of the ladder-shaped 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.
3.2.2 Sentence predicative speech , is similar to the assembler language .
3.2.3 Logic functional diagram language, continue to use semiconductor logic block diagram is it express to come, one operation frame generally show one function on the left draw introduction , on the right paint and export.
4 Use the programe of STEP7
4.1 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.
4.2 Configuration one station, configuration one station to appoint you want programmable controller that use, such as S7300 , S7400 ,etc..
4.3 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 needn't generally be revised and produced automatically by the procedure. The characteristic of the template can carry on assignment with the parameter too.
4.4 Configuration network and communication connect, the foundation of the communication is the configuration network in advance , is it is it establish one meet control sub network of scheme of you , set up network characteristic , set up network connect characteristic and connection station need of networking any to want to that is to say.
PLC foundation
Operation principle of the controller that can programme
PLC adopts the working way scanned in circulation, when PLC carries out user's procedure , CPU scans the ladder-shaped 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 ; The timer is presetted; 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 , user's memory is checked etc. and operated. Communication operates the stage of serving: PLC and some intelligent object communication, the order that the response programmable device typed in, upgrade display content of the programmable device ,etc.. Content of operating etc. that PLC is in the state of stopping (STOP ) to only carry on the inside and to deal with and have the service of ports with outside. Deal with the inside when PLC is in the state of operating (RUN ) , setting up service of ports , proceduing inputting , procedure carrying out , proceduring to export outside, is been circulating and scanning the work all the time .
1, Input and deal with stage
Input and deal with too and let introduction sample. At this stage, PLC is read into breaking the state openly of all input end sons by way of scanning, and store reading the information entered in the corresponding image register in the memory, inputting and videoing the register here and is broken, then enter the procedure and carry out stage.
2, The procedure carries out stage
Carrying out stage in the procedure, PLC scans and carries out user's procedure sentence by sentence, meet and jump the order of rotating, according to shifting the trend that the condition decides the procedure. User's procedure involves until states of exporting of introduction , PLC reads on last stage and adopts the corresponding sub state of input end entered from inputting while videoing the register,to read the corresponding present state of videoing the register from exporting while videoing the register, carrying on logic operation according to user'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 component 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 computer industry, its hardware is basically the same micro-computer:
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; Power check, memory, I / 0 and timer state of alert, and users can diagnose the procedures grammatical mistakes.
2, Memory storage system software
Memory storage system software called System memory program memory. Storage application software known as the user program memory Memory
3, Power
Power in the PLC system as a whole played a very important in the role. General AC voltage fluctuations in +10% (+15%), within can not take other measures to connect directly to the PLC to theAC Internet.
4, Input and output devices (I / O modules)
I / O module is the scene UO CPU and other external devices or equipment connectivity between components. External input signal is transformed into a CPU can accept the signal, CPU or the output signal of the need to transform into a control signal to drive the control object, to ensure the normal work of the whole system.
5, Programming
Programming device programmer users procedures applicable to the compilation, editing, debugging inspection and surveillance, You can also call its keyboard and display to the PLC within the state and some system parameters. Through communication port and the CPU link connecting complete man-machine dialogue.
6, External monitoring system equipment
External PLC equipment are generally equipped with printers, EPROM writers, High-resolution color screen graphics such external monitoring system equipment.
Main function of PLC
PLC uses the face to be very wide, which develop very fast industrial automation device, to occupy the important position inside in the automation of the factory (FA ) and CIMS (CIMS ). PLC system is generally formed by following basic function:
1,Control the function:
Logic control , controlling , counting numerical control and making regularly, the order is controlled.
2, Gather , store and deal with the function in data:
Mathematical operation function , data processing , simulation data processing(whether PID , total mark strain wave).
3,Input / output the interface and recuperate the function:
Having A/D, D/A changes the function, finishes the control on analog quantity and regulation through I/O module . Having temperature survey interface, it is even to connect various kinds of resistance or the electricity directly.
4, Communication , network savvy:
Which Can carry on long-range I/O control, many sets of PLC can network between each other , communication, outside device can compile with one or many signal , preface of controller deal with the units, realize the procedure and data interchange.
5, The function of the man-machine interface:
Offered to operators it in order to monitor the machine / the information of the course with essential work. Allow the operator , PC system and its application program interaction , in order to make decision and adjust.
6, Programming , debugging ,etc:
Use complexity different hold , portabling and tabletop type programmable device , work station and operation are rejected , carry on programming , debug , monitor , test and write down, and type out the procedure file through the printer.
PLC基礎
1.1 PLC的發(fā)展歷程
在工業(yè)生產(chǎn)過程中，大量的開關量順序控制，它按照邏輯條件進行順序動作，并按照邏輯關系進行連鎖保護動作的控制，及大量離散量的數(shù)據(jù)采集。傳統(tǒng)上，這些功能是通過氣動或電氣控制系統(tǒng)來實現(xiàn)的。1968年美國GM（通用汽車）公司提出取代繼電氣控制裝置的要求，第二年，美國數(shù)字公司研制出了基于集成電路和電子技術的控制裝置，首次采用程序化的手段應用于電氣控制，這就是第一代可編程序控制器，稱Programmable Controller（PC）。
個人計算機（簡稱PC）發(fā)展起來后，為了方便，也為了反映可編程控制器的功能特點，可編程序控制器定名為Programmable Logic Controller（PLC）。
上世紀80年代至90年代中期，是PLC發(fā)展最快的時期，年增長率一直保持為30~40%。在這時期，PLC在處理模擬量能力、數(shù)字運算能力、人機接口能力和網(wǎng)絡能力得到大幅度提高，PLC逐漸進入過程控制領域，在某些應用上取代了在過程控制領域處于統(tǒng)治地位的DCS系統(tǒng)。
PLC具有通用性強、使用方便、適應面廣、可靠性高、抗干擾能力強、編程簡單等特點。PLC在工業(yè)自動化控制特別是順序控制中的地位，在可預見的將來，是無法取代的。
1.2 PLC的構成
從結構上分，PLC分為固定式和組合式（模塊式）兩種。固定式PLC包括CPU板、I/O板、顯示面板、內存塊、電源等，這些元素組合成一個不可拆卸的整體。模塊式PLC包括CPU模塊、I/O模塊、內存、電源模塊、底板或機架，這些模塊可以按照一定規(guī)則組合配置。
1.3 CPU的構成
CPU是PLC的核心，起神經(jīng)中樞的作用，每套PLC至少有一個CPU，它按PLC的系統(tǒng)程序賦予的功能接收并存貯用戶程序和數(shù)據(jù)，用掃描的方式采集由現(xiàn)場輸入裝置送來的狀態(tài)或數(shù)據(jù)，并存入規(guī)定的寄存器中，同時，診斷電源和PLC內部電路的工作狀態(tài)和編程過程中的語法錯誤等。進入運行后，從用戶程序存貯器中逐條讀取指令，經(jīng)分析后再按指令規(guī)定的
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