dcs原理與plc基礎(chǔ)外文翻譯

1、<p><b>　　中文6790字</b></p><p>　　DCS principle and PLC foundation</p><p>　　DCS principle </p><p>　　Distributed Control System (DCS) carries on the centralism monitor,

2、the operation, the management and the disperser control which is one kind of new control technology using the computer technology to the production process. DCS is base on the computer technology, the signal processing t

3、echnology, the survey control technology, the correspondence network technology, the CRT technology, the graphical display technology and the man-machine connection technology mutually seeps the development to pr</p&g

4、t;<p>　　Basic component of DCS</p><p>　　The logic structure of the system needs realizing by the physics structure. We can sum up their physics structure as the structure of the type of " a gleam

5、 of past three " simply . " first line " refers to its skeleton computer network, " the three " means that join three kinds of different kinds of nodes in the network: Face on-the-spot I/O which

6、 is accused of the course scene to control and stand; Facing the attenbant's operator's station; Facing DCS supervise the administrative staff's engi</p><p>　　I/O controls the station live &

7、lt;/p><p>　　An on-the-spot I / O is controlled and stood to finish dealing with and realizing the network node of digital control DDC (Direct Digital Control ) directly to on-the-spot I/O of course, there are t

8、hree main functions: </p><p>　　1, which carried on digitization of various kinds of on-the-spot course amount (such as the flow , pressure ), and the quantity after digitizing is stored in the memory , form

9、one keep the same with on-the-spot course amountly, can one-one is it video in real time according to actual running situation with newer on-the-spot course quantity to change in real timing; </p><p>　　2, th

10、e real-time data gathering our station are sent to operator's station , standing and other engineers live through the network FO control the station, in order to realize the supervision and control of the whole syste

11、m, at the same time it is stood the message issued by operator's standing , engineer that can also receive , in order to realize that establishes artificial control or parameter to our station of the scene. </p>

12、;<p>　　3, calculation and closing ring controlling , in order to control etc. IN realizing the part and automaticallying control in our station , return circuit , algorithm whose some classical algorithm generally

13、, can remove theatrical makeup and costume non-standard algorithm , complicated algorithm. </p><p>　　Operator's station </p><p>　　The operator of DCS deals with all functions of man-machine

14、interface (MMI-Man Machine Interface ) related to operating and operating at station, embody in and offer the man-machine interface for operating attendants mainly, enable operators to understand on-the-spot operation st

15、ate , to present value of various kinds of operation parameters , and have unusual situations to take place etc. In time through operator's station, and can control and regulate the craft course through the input equ

16、ipme</p><p>　　1, the simulation flow chart of the production process (namely by imitating production device and production line that the figure expresses), which wins a bid of real-time status with all key d

17、ata ,to control parameter and equipment; </p><p>　　2, the warning window: By arranging the time order way (namely the most emerging alarm ranks the top of the window ) and listing the unusual situation appea

18、ring in production processes , if number value restricts . Reporting to the police should include time , unusual state and value , confirming by operator and unusual brief illustration to tabulate already of the unusual

19、data to unusually appear ; </p><p>　　3, the real-time trend shows: With curve say come out change recently, producting process of data, so that the operator understands its development and change to some ext

20、ent, and can help to analyse the running situation of the production process .which Can generally show the trend curves of 4-8 data in the same system of coordinates , so can compare with all relevant data ,to make the a

21、nalysis on on-the-spot situation very more clearly. </p><p>　　The engineer stands </p><p>　　It is disposed to DCS off-line that the engineer stands, configuration and network node supervised , c

22、ontrolled , 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 st

23、and 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. </p><p>　　Systematic network </p><p&

24、gt;　　It is all some isolated nodes that on-the-spot I/O is controlled and stands , stands at operator's station and engineer, to finish one's own work each. If none of unified coordination can not form the intact

25、 system, the systematic network offers the foundation for coordinating , which becomes the core of the whole system. </p><p>　　1, Network characteristic </p><p>　　Different from some network tha

26、t general office automation adopts, the communication network that DCS adopts was used for the control and management of have the industrial production process, so, it should possess the characteristics of the followin

27、g : </p><p>　　● Real-time character is good, respond fast dynamically </p><p>　　● Meet the abominable on-the-spot environment of industry </p><p>　　● Dependability is high </p

28、><p>　　● Opening is good </p><p>　　2, Network structure </p><p>　　Early LAN with better real-time character of often adopt IEEE802.4 making brand total network or IEEE802.5 to make th

29、e card surround the network alone etc. of information management network of DCS control system. But no matter domestic or abroad, which uses most is IEEE802.3 CSMA/CD Ethernet at present. Ethernet enters industry and com

30、es from its low cost , opening , extensive development and support of using the software and hardware live, what it uses the most extensive network technology at p</p><p>　　DCS controller function block: DCS

31、 not only able to complete the functions of the original analog instruments, and much higher than analog instruments. This is because it uses advanced computer technology, communication technology, CRT technology and con

32、trol technology 4C technology. Using digital control after the pre-deposited in the controller ROM of the algorithm is infinite, each representative of an algorithm kinds of functions. These features in the simulated ins

33、trument is achieved with a</p><p>　　DCS controller mainly by the CPU, ROM, RAM, E2PROM, address setting switches and other components. CPU complete the operation, ROM is used to keep the operating system, fu

34、nction block libraries, function blocks are arranged in the ROM is set in, the user can not be changed. RAM is used to save CPU computational results and I / O signals. E2PROM keep even with the function block into the c

35、ontrol program. Under the power, the control program is not lost. Moreover, the control scheme not suitable, </p><p>　　1,Development course of PLC</p><p>　　In the course of industrial production

36、, 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 t

37、he 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 continue

38、d the electric control</p><p>　　After the personal computer ( abbreviated as PC ) develops, for being convenient, in order to reflect the function characteristic of the programmable controller too, can progr

39、amme controller name Programmable Logic Controller (PLC).</p><p>　　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 growt

40、h 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

41、gradually, has replaced and in DCS system ruling position on the course controlled field in some is used. </p><p>　　PLC have commonability to be strong easy to use meeting surface wide , dependability high ,

42、 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 repla

43、ce. </p><p>　　1.2 Composition of PLC </p><p>　　Divide from structure, PLC is divided into a regular type and sectional (module type ) two kinds</p><p>　　Regular type PLC including C

44、PU 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 t

45、he framework, the module can be made up and disposes according to certain rule. </p><p>　　1.3 Composition of CPU </p><p>　　CPU is a core of PLC, functions as nerve center, each set of PLC has o

46、ne 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

47、 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 </p

48、><p>　　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 bu

49、s and relevant circuit. The memory is used for storing the procedure and data mainly, is indispensable composition unit PLC. </p><p>　　In user's view , it is unnecessary to analyse the inside circuit of

50、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 work

51、ing 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 partici</p&g

52、t;<p>　　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 sca

53、le . </p><p>　　1.4 I/O module</p><p>　　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 temp

54、orarily 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

55、 opposite. I/O is divided and imported (DI) for the switch amount, the switch amount is exported (DO), analog quantity is inp</p><p>　　Commonly used I/O is classified as follows: </p><p>　　Switc

56、h 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

57、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.. </p><p>　　B

58、esides 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 accord

59、ing 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 . <

60、/p><p>　　1.5 Power module </p><p>　　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 inputtin

61、g 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). </p><p>　　1.6 The baseplate or the framework</p&g

62、t;<p>　　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 , rea

63、lize the connection among every module , make every module form a whole . </p><p>　　1.7 Other equipment of PLC system </p><p>　　1. 7.A programming equipment: The programmable device is that PLC

64、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

65、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 programmabl</p

66、><p>　　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 stat

67、ion 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.</p><p>　　1.8 The communication of PL

68、C is networked </p><p>　　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 auto

69、matic system integration project is more and more remarkable, even someone proposes the view statement that " the network is the controller " .</p><p>　　PLC have function that communication network

70、, 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

71、, 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 mainl

72、y now. </p><p>　　2. Design basic principle of PLC control system</p><p>　　2.1 Meet the control request which is accused of the target maximumly. </p><p>　　2.2 On the premise of meet

73、ing control request , is it make control system simple , economy , use and maintain convenient to make every effort. </p><p>　　2.3 Guarantee the control system is safe and reliable. </p><p>　　2.

74、4 Consider the development of production and improvement of the craft should leave the surplus properly while choosing PLC capacity. </p><p>　　3. PLC software system and daily programming language </p>

75、<p>　　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

76、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 fro

77、m already. User procedure whether user according to on-the-spot control request, </p><p>　　3.2 Programming language that PLC offers </p><p>　　3.2.1The ladder-shaped picture language of standard

78、language is a kind of most frequently used languages of ours too, it has the following characteristic </p><p>　　3.2.1.1 It is a kind of figure language, term of continuing to use relay contact , coil that t

79、he 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. </p><p>　　3.2.1.2 The contact (cont

80、act ) 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 c

81、onnected . </p><p>　　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 . </p><p>　　3.2.1.4 Inside relay ,

82、 counter , register ,etc. can't directly control outside load , can only make middle result to use while supporting CPU . </p><p>　　3.2.1.5 PLC scans the incident according to circulation, carry out alon

83、g 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 t

84、he same scanning. </p><p>　　3.2.2 Sentence predicative speech , is similar to the assembler language . </p><p>　　3.2.3 Logic functional diagram language, continue to use semiconductor logic bloc

85、k diagram is it express to come, one operation frame generally show one function on the left draw introduction , on the right paint and export. </p><p>　　4 Use the programe of STEP7</p><p>　　4.1

86、 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 u

87、nder this project. </p><p>　　4.2 Configuration one station, configuration one station to appoint you want programmable controller that use, such as S7300 , S7400 ,etc.. </p><p>　　4.3 Configurati

88、on 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&#

89、39;t generally be revised and produced automatically by the procedure. The characteristic of the template can carry on assignment with the parameter too. </p><p>　　4.4 Configuration network and communicati

90、on 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 chara

91、cteristic and connection station need of networking any to want to that is to say. </p><p>　　PLC foundation </p><p>　　Operation principle of the controller that can programme </p><p&

92、gt;　　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 prio

93、rity order that the sentence is arranged , it is a kind of serial working way. </p><p>　　Initialize at first after the electricity on PLC: Auxiliary , special auxiliary , auxiliary regional zero clearing of

94、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

95、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</p><p>　　1, Input and deal with stage </p

96、><p>　　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 c

97、orresponding image register in the memory, inputting and videoing the register here and is broken, then enter the procedure and carry out stage. </p><p>　　2, The procedure carries out stage </p><p

98、>　　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 procedur

99、e. 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 corr