plc毕业设计说明书外文文献翻译.doc

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1、 2012届毕业设计说明书 外文文献翻译 院 、 部： 电气与信息工程学院 学生姓名： 指导教师： 职称 副教授 专 业： 班 级： 完成时间： PLC Theory And ApplicationsA programmable logic controller, PLC, or programmable controller is a small computer used for automation of real-world processes, such as control of machinery on factory assembly lines. The PLC usuall

2、y uses a microprocessor. The program can often control complex sequencing and is written by skilled engineers. The program is stored in battery-backed memory and/or EEPROMS.Definition is: a digital electronic computer operating system specifically designed for using in the industrial environment. It

3、 adopts a category programmable memory for its internal storage procedures, the implementation of the logical operations, sequence control, timing, counting and arithmetic operations such as user-oriented instructions, and through digital or analog input / output control various types of machinery o

4、r production processes.1 PLC Development Course In industrial production processes, a large number of switches in order to control it in a logical sequence of moves conditions, and in accordance with the logic of relations chain protection movements control, and a large number of discrete volume dat

5、a collection. Traditionally, these functions are achieved through pneumatic or electrical control system. 1968 U.S. GM (General Motors) company replaced following electrical control devices, the second year, the U.S. company has developed a number of integrated circuits and electronic technology-bas

6、ed control devices, the first use of the means of the procedures applied to the electrical control, and this is the first generation programmable controller said Programmable Controller (PC)The functionality of the PLC has evolved over the years to include typical relay control, sophisticated motion

7、 control, process control, distributed control systems and complex networking.Personal computer (PC for short) has been developed, in order to facilitate, but also to reflect the functional characteristics of programmable controllers.Programmable controller is named Programmable Logic Controller (PL

8、C), now PC is often called PLC.2 Programmable Controller Basic TenetsPLC is based on computers, and applies to industrial motor controlling work site. It originated from relay control devices, but it does relay devices, the physical process of controlling through circuits, and mainly relies on the o

9、peration of PLC memory stored in the procedures for the realization of their information into and out of control.PLCs were invented as less expensive replacements for older automated systems that would use thousands of relays and cam timers. Often, a single PLC can be programmed to replace thousands

10、 of relays. Programmable controllers were initially adopted by the automotive manufacturing industry, where software revision replaced the re-wiring of hard-wired control panels.PLC-based computer, but can not be equated with ordinary computers. Information is transformed into a universal computer,

11、and it is only considered by information itself. No matter information goes into and out of it; it can be a good human interface. And the PLC will also consider the reliability of information in and out, real-time, and the use of information and other issues. Special consideration must be given to h

12、ow to adapt to the industrial environment, such as the ease of installation, interference and other issues.2.1 PLC Composition PLC is divided into two forms of fixed and modular (modular) in structure. Fixed PLC includes CPU boards, I/O boards, and panels shown, within blocks, electricity. All these

13、 elements into a portfolio as a whole are not detachable. Modular PLC includes CPUModules, I/O module, memory, power supply module, or ill bed, these modules will be in accordance with the rules of portfolio allocation. 2.1.1 CPU Composition CPU is the core of PLC, and it plays a central role. At le

14、ast one PLC has one CPU, the PLC system procedures is to receive and store the users functional procedures and data collection methods used by the scanning of the device or sent to the state data, and in the execution, at the same time, diagnostic power and the internal circuits PLC programming proc

15、ess and the work of the grammatical mistakes. During operation, from memory, the article retrieval user procedures is directively analyzed later by a corresponding directive mandates control signals to the command control circuits. For example: CPU mainly by arithmetic unit, the controller, register

16、 and the links between them to achieve data, control and pose a challenge, CPU module also includes outlying chips, and the bus interface circuits. Procedures exist mainly for storage and data is an integral PLC modules. 2.1.2 I/O Module PLC interfaces with the electrical circuit, and that is achiev

17、ed through the importation of export segment (I/O) completed. I/O module integration of the PLC I/O circuit, the input signal into Short-term stored equipment reflects state export points also reflects export flip-latch state. Import module will be converted into digital signals into electrical sign

18、al PLC system, and the output module opposite. I/O into switching to import (DI), the export volume of switches (do), the volume of simulation (AI), analog output volume (AO) module2.1.3 Power Module PLC power provides power for the IC modules. At the same time, some of them also work for the import

19、ation of power circuit to provide 24V. Power input divided into types below: sharing power (220VAC or 110VAC), direct current power supply (commonly used to 24VAC) 3 Programmable Controller Achieving Control Points Transformation of information I/O can be achieved by physical, which is could be cons

20、idered to be two basic points.Information on their operations into and out of storage exists in the procedures of PLC. PLC procedures established manufacturers of the system procedures (irrevocable), and users develop their own applications (users) procedures. Operating system platforms provide proc

21、edures, and procedures for the PLC signal and reliable operation of the public with the information necessary conversion. Users control procedures designed by the users. What kind of control, due to what the user procedures. Reliable physical realization mainly relies on anyone else (input) and (out

22、put) circuit. PLCs I/O circuits are specially designed. Of a filter circuit to input signal to eliminate high-frequency interference. But with the internal computer circuits, electricity is isolated and it also relies on photocoupling networking components. Guangou components export relays networkin

23、g exports from electricity within and outside the circuit, or. A power output circuit also enlarged to be sufficient to general industrial control components, such as electromagnetic valves, contact devices, and so on. For example:I/O circuits contains a lot of sorts, each entry points or export poi

24、nts to a circuit I or O. PLC with how I/O point, the general will use a number of I/O circuit. But because the highly integrated circuit provided them, so size is not large share. Constantly monitored the importation of circuit status and pending in the importation of Short-term storing equipment. E

25、ach entry point has a corresponding memory of their information Short-term storing equipment Export circuit to export flip-latch devices messaging to export points. Export flip-latch and the output is also gathers Import and export of flip-latch and Short-term storing equipment here are the actual d

26、evice of PLC processors I/O the register. They exchange information through computers and computer memory bus, and primarily by the realization of operating system procedures. Short-term storing equipment is to lose people read the information within the PLC, it is said that the importation of regen

27、eration. PLC is within the open storage of specialized information shine upon area. Each of the district counterpart spaces (bit) as input relays, or those soft contacts. These positions into one that includes links, home to multiple broken into 0. Because it is the state of renewable received, so t

28、hat it is reflected in the imported state. Export flip-latch and the PLC memory areas are exported shine upon counterpart. 1-export flip-latch have a hard place (bit) with its counterpart, the place known as export relays, or that exporting coil. By operating system procedures, and the output relays

29、 shine upon the state to export flip-latch. Also known as the shine upon exporting renewable. Is the main operating system on renewable export procedures achieved? Thus, users only need to be procedures that exist in the area of shine upon export shine upon their zone, especially in the importation

30、of the time series is converted into the output time series. This is a logic and data processing. The PLC is a powerful command system, the procedures to prepare to meet this requirement is entirely possible, but also relatively easy. 4 Programmable Controller Achieve Control Of The Process Briefly,

31、 PLC controlling process is usually achieved: Of renewable - to users operating procedures - to export renewable - further importation of renewable - to users operating procedures - to export renewable: never stop to the cycle of repeated carried out. With the above-mentioned process, the realizatio

32、n of a PLC control is clearly possible. Because: With the importation of renewable, can be imported by the import control circuit input shine upon information deposited PLC District; By users operating procedures, and the output will be used after the district shine upon information; After exporting

33、 renewable exporting flip-latch will be reflected shine upon export zone status, and a corresponding export through export circuit. Also as a result of this process is never ceasing to cycle repeatedly carried out, it is always reflect input from the changes. Response time is only slightly behind. O

34、f course, this should not lag too much, otherwise achieved control less timely lose control of significanceTo this end, the PLC work faster. Speed, execution time is short, the realization is PLC controlled. In fact, it is the speed soon, the implementation of a directive, several more elsewhere, sc

35、ores elsewhere, but only 0.1 of the few, or 0.0 few refinements. And the speed is constantly improving. In addition to operational users I/O renewable and procedures, but also do public address work Report processing: cycle time monitoring, and engineered services and communications processing. Cont

36、rol cycle time in order to avoid dead cycle in order to avoid duplication of procedures cannot be repeated continuously. Approach is the use of man (Watching dog). As long as the cycle of overtime, it can report or consequential. The external services is acceptable for PLC programming by its operati

37、on, or through interfaces to export equipment, such as printers output data Communications processing is a PLC or computer, or other industrial control devices or the exchange of information among intelligence components. This is also enhanced PLC control needsIn other words, the actual process alwa

38、ys PLC: public address -I/O renewable - users operating procedures - to the public address -: repeated constantly.4.1 Programmable Controller Means To Achieve Control This constant repetition of the operation procedures is used to achieve that control scanning. Is a computer-based real-time control?

39、 In addition, there are computers for control interruption. Interruption in the form of applications to be processed first interruption control, the procedure was to stop the operation after the operation is, in turn, to deal with the interruption of work (the interruption of services operating proc

40、edures). Pending End interruption, and return to the original operational procedures. Which control needs to be addressed, which went for the interruption? Which has no treatment, will not be ignored. Clearly, the interruption of ways and scanning mode is different. Interruption in the form of compu

41、ter to be utilized to the full, urgent tasks are to be dealt with in a timely manner. However, if at the same time to deal with several tasks that must be done? Priority will also be much easier to high-level, low? Care less than it might appear. Therefore, the interruption of work is not suited to

42、the daily use of the site. However, PLC scanning method is used mainly in cases of exclusion or suspension. Namely, a large number of controls by scanning all manner of dealing with individual needs, allowing the interruption of scanning operation procedures, turn to deal with it. This can be done t

43、aking into account all the control; the individual can carry out emergency treatment. Actually the process of PLC is more complex than we mentioned here, the analysis of its basic tenets, some theoretical issues. If the personnel on the above can enter a change, physical realization - information pr

44、ocessing, I/O call Cumming space, time - scanning method supplemented by the interruption, as a way to study and understand it, and good understanding of PLC is how to achieve control and good grasp of the basic principles of PLC points. For more in-depth, in the further course of study, will make a

45、 specific presentation. 5 Programmable Controller Basic Characteristics The operating principles are those from the discussion of PLC, PLCs input and output are mutually separated in physics, which is linked to its existing storage operation on the procedures to achieve. It into a relevant, and not

46、rely on physics, not a line; But by the information process, using soft logic links. Its work is based on the use of good information. Information is material and energy with its own laws. Facilitate the processing of information, facilitate communication and facilitate storage; Information may also

47、 be trusted, and so on. It is precisely because of these characteristics of information, decisions of the basic characteristics of the PLC.The examples of PLCs four characteristics are as follow:5.1 Functional Rich PLC functions are very rich. This was mainly related to the processing of information

48、 rich store of information systems and internal directives devices. Scores up its command; several hundred may be a logic problem for all types of data processing also. Where ordinary computer can do, it can be done. Its internal devices that exist in the data storage area is a wide range of capacit

49、y ambitious. I/O relays can be used to store input, a point of information, fewer scores, and more up to thousands and tens of thousands or even ten thousands. This means that it can carry out so many I/O points into and out of information used for such large-scale control. Its internal various relays, representing intermediate relays, the number more. A place c