關(guān)于plc的畢業(yè)設(shè)計(jì)外文翻譯

1、<p>　　ONE、PLC overview</p><p>　　Programmable controller is the first in the late 1960s in the United States, then called PLC programmable logic controller (Programmable Logic Controller) is used to repl

2、ace relays. For the implementation of the logical judgment, timing, sequence number, and other control functions. The concept is presented PLC General Motors Corporation. PLC and the basic design is the computer function

3、al improvements, flexible, generic and other advantages and relay control system simple and easy to operate, s</p><p>　　In the mid-1970s, the PLC has been widely used as a central processing unit microproces

4、sor, import export module and the external circuits are used, large-scale integrated circuits even when the PLC is no longer the only logical (IC) judgment functions also have data processing, PID conditioning and data c

5、ommunications functions. International Electro technical Commission (IEC) standards promulgated programmable controller for programmable controller draft made the following definition : program</p><p>　　Firs

6、t, high reliability, anti-interference capability;</p><p>　　Second，programming visual, simple;</p><p>　　Third, adaptability good;</p><p>　　Fourth functional improvements, strong fun

7、ctional interface.</p><p>　　TWO、History of PLC</p><p>　　Programmable Logic Controllers (PLC), a computing device invented by Richard E. Morley in 1968, have been widely used in industry includin

8、g manufacturing systems, transportation systems, chemical process facilities, and many others. At that time, the PLC replaced the hardwired logic with soft-wired logic or so-called relay ladder logic (RLL), a programming

9、 language visually resembling the hardwired logic, and reduced thereby the configuration time from 6 months down to 6 days [Moody and Morley, </p><p>　　Although PC based control has started to come into plac

10、e, PLC based control will remain the technique to which the majority of industrial applications will adhere due to its higher performance, lower price, and superior reliability in harsh environments. Moreover, according

11、to a study on the PLC market of Frost and Sullivan [1995], an increase of the annual sales volume to 15 million PLCs per year with the hardware value of more than 8 billion US dollars has been predicted, though the price

12、s of </p><p>　　Though PLCs are widely used in industrial practice, the programming of PLC based control systems is still very much relying on trial-and-error. Alike software engineering, PLC software design

13、is facing the software dilemma or crisis in a similar way. Morley himself emphasized this aspect most forcefully by indicating </p><p>　　`If houses were built like software projects, a single woodpecker coul

14、d destroy civilization.”</p><p>　　Particularly, practical problems in PLC programming are to eliminate software bugs and to reduce the maintenance costs of old ladder logic programs. Though the hardware cost

15、s of PLCs are dropping continuously, reducing the scan time of the ladder logic is still an issue in industry so that low-cost PLCs can be used.</p><p>　　In general, the productivity in generating PLC is far

16、 behind compared to other domains, for instance, VLSI design, where efficient computer aided design tools are in practice. Existent software engineering methodologies are not necessarily applicable to the PLC based softw

17、are design because PLC-programming requires a simultaneous consideration of hardware and software. The software design becomes, thereby, more and more the major cost driver. In many industrial design projects, more than

18、of the </p><p>　　In addition, current PLC based control systems are not properly designed to support the growing demand for flexibility and reconfigurability of manufacturing systems. A further problem, impe

19、lling the need for a systematic design methodology, is the increasing software complexity in large-scale projects.</p><p>　　The objective of this thesis is to develop a systematic software design methodology

20、 for PLC operated automation systems. The design methodology involves high-level description based on state transition models that treat automation control systems as discrete event systems, a stepwise design process, an

21、d set of design rules providing guidance and measurements to achieve a successful design. The tangible outcome of this research is to find a way to reduce the uncertainty in managing the control so</p><p>　　

22、Three、now of PLC</p><p>　　From the structure is divided into fixed PLC and Module PLC, the two kinds of PLC including CPU board, I/O board, display panel, memory block, power, these elements into a do not re

23、move overall. Module type PLC including CPU module, I/O modules, memory, the power modules, bottom or a frame, these modules can be according to certain rules combination configuration.</p><p>　　In the user

24、view, a detailed analysis of the CPU's internal unnecessary, but working mechanism of every part of the circuit. The CPU control works, by it reads CPU instruction, interprets the instruction and executes instruction

25、s. But the pace of work by shock signal control. </p><p>　　Unit work under the controller command used in a digital or logic operation.In computing and storage register of computation result, it is also amon

26、g the controller command and work. CPU speed and memory capacity is the important parameters for PLC , its determines the PLC speed of work, IO PLC number and software capacity, so limits to control size. </p><

27、;p>　　Central Processing Unit (CPU) is the brain of a PLC controller. CPU itself is usually one of the microcontrollers. Aforetime these were 8-bit microcontrollers such as 8051, and now these are 16-and 32-bit microco

28、ntrollers. Unspoken rule is that you’ll find mostly Hitachi and Fujicu microcontrollers in PLC controllers by Japanese makers, Siemens in European controllers, and Motorola microcontrollers in American ones. CPU also tak

29、es care of communication, interconnectedness among other parts of PL</p><p>　　System memory (today mostly implemented in FLASH technology) is used by a PLC for a process control system. Aside form. this oper

30、ating system it also contains a user program translated forma ladder diagram to a binary form. FLASH memory contents can be changed only in case where user program is being changed. PLC controllers were used earlier inst

31、ead of PLASH memory and have had EPROM memory instead of FLASH memory which had to be erased with UV lamp and programmed on programmers. With the use o</p><p>　　User memory is divided into blocks having spec

32、ial functions. Some parts of a memory are used for storing input and output status. The real status of an input is stored either as “1”or as “0”in a specific memory bit/ each input or output has one corresponding bit in

33、memory. Other parts of memory are used to store variable contents for variables used in used program. For example, time value, or counter value would be stored in this part of the memory.</p><p>　　PLC contro

34、ller can be reprogrammed through a computer (usual way), but also through manual programmers (consoles). This practically means that each PLC controller can programmed through a computer if you have the software needed f

35、or programming. Today’s transmission computers are ideal for reprogramming a PLC controller in factory itself. This is of great importance to industry. Once the system is corrected, it is also important to read the right

36、 program into a PLC again. It is also good to chec</p><p>　　Almost every program for programming a PLC controller possesses various useful options such as: forced switching on and off of the system input/out

37、puts (I/O lines), program follow up in real time as well as documenting a diagram. This documenting is necessary to understand and define failures and malfunctions. Programmer can add remarks, names of input or output de

38、vices, and comments that can be useful when finding errors, or with system maintenance. Adding comments and remarks enables any techn</p><p>　　Electrical supply is used in bringing electrical energy to centr

39、al processing unit. Most PLC controllers work either at 24 VDC or 220 VAC. On some PLC controllers you’ll find electrical supply as a separate module. Those are usually bigger PLC controllers, while small and medium seri

40、es already contain the supply module. User has to determine how much current to take from I/O module to ensure that electrical supply provides appropriate amount of current. Different types of modules use different a<

41、/p><p>　　This electrical supply is usually not used to start external input or output. User has to provide separate supplies in starting PLC controller inputs because then you can ensure so called “pure” supply

42、 for the PLC controller. With pure supply we mean supply where industrial environment can not affect it damagingly. Some of the smaller PLC controllers supply their inputs with voltage from a small supply source already

43、incorporated into a PLC.</p><p>　　Four、PLC design criteria </p><p>　　A systematic approach to designing PLC software can overcome deficiencies in the traditional way of programming manufacturing

44、 control systems, and can have wide ramifications in several industrial applications. Automation control systems are modeled by formal languages or, equivalently, by state machines. Formal representations provide a high-

45、level description of the behavior of the system to be controlled. State machines can be analytically evaluated as to whether or not they meet the desired g</p><p>　　In modern manufacturing, systems are chara

46、cterized by product and process innovation, become customer-driven and thus have to respond quickly to changing system requirements. A major challenge is therefore to provide enabling technologies that can economically r

47、econfigure automation control systems in response to changing needs and new opportunities. Design and operational knowledge can be reused in real-time, therefore, giving a significant competitive edge in industrial pract

48、ice.</p><p>　　Studies have shown that programming methodologies in automation systems have not been able to match rapid increase in use of computing resources. For instance, the programming of PLCs still rel

49、ies on a conventional programming style with ladder logic diagrams. As a result, the delays and resources in programming are a major stumbling stone for the progress of manufacturing industry. Testing and debugging may c

50、onsume over 50% of the manpower allocated for the PLC program design. Standards [IEC 60</p><p>　　A systematic approach will increase the level of design automation through reusing existing software component

51、s, and will provide methods to make large-scale system design manageable. Likewise, it will improve software quality and reliability and will be relevant to systems high security standards, especially those having hazard

52、ous impact on the environment such as airport control, and public railroads.</p><p>　　The software industry is regarded as a performance destructor and complexity generator. Steadily shrinking hardware price

53、s spoils the need for software performance in terms of code optimization and efficiency. The result is that massive and less efficient software code on one hand outpaces the gains in hardware performance on the other han

54、d. Secondly, software proliferates into complexity of unmanageable dimensions; software redesign and maintenance-essential in modern automation systems-becomes</p><p>　　Today, the primary focus of most desig

55、n research is based on mechanical or electrical products. One of the by-products of this proposed research is to enhance our fundamental understanding of design theory and methodology by extending it to the field of engi

56、neering systems design. A system design theory for large-scale and complex system is not yet fully developed. Particularly, the question of how to simplify a complicated or complex design task has not been tackled in a s

57、cientific way. Further</p><p>　　From a logical perspective, PLC software design is similar to the hardware design of integrated circuits. Modern VLSI designs are extremely complex with several million parts

58、and a product development time of 3 years [Whitney, 1996]. The design process is normally separated into a component design and a system design stage. At component design stage, single functions are designed and verified

59、. At system design stage, components are aggregated and the whole system behavior and functionality is te</p><p>　　Five、AK 1703 ACP</p><p>　　Following the principle of our product development, A

60、K 1703 ACP has high functionality and flexibility, through the implementation of innovative and reliable technologies, on the stable basis of a reliable product platform.</p><p>　　For this, the system concep

61、t ACP (Automation, Control and Protection) creates the technological preconditions. Balanced functionality permits the flexible combination of automation, telecontrol and communication tasks. Complemented with the scalab

62、le performance and various redundancy configurations, an optimal adaptation to the respective requirements of the process is achieved.</p><p>　　AK 1703 ACP is thus perfectly suitable for automation with inte

63、grated telecontrol technology as:</p><p>　　? Telecontrol substation or central device</p><p>　　? Automation unit with autonomous functional groups</p><p>　　? Data node, station cont

64、rol device, front-end or gateway</p><p>　　? With local or remote peripherals</p><p>　　? For rear panel installation or 19 inch assembly</p><p>　　? Branch-neutral product, therefore

65、versatile fields of application and high product</p><p><b>　　stability</b></p><p>　　? Versatile communication</p><p>　　? Easy engineering</p><p>　　? Plug &a

66、mp; play for spare parts</p><p>　　? Open system architecture</p><p>　　? Scalable redundancy</p><p>　　? The intelligent terminal - TM 1703</p><p>　　The Base Unit AK 1703

67、 ACP with Peripheral Elements has one basic system element CP-2010/CPC25 (Master control element) and CP-2012/PCCE25 (Processing and communication element) ,one bus line with max. 16 peripheral elements can be connected.

68、</p><p>　　CP-2010/CPC25 Features and Functions</p><p>　　System Functions:</p><p>　　? Central element,coordinating all system services</p><p>　　Central hub function for

69、all connected basic system elements</p><p>　　? Time management</p><p>　　Central clock of the automation unit</p><p>　　Setting and keeping the own clock`s time with a resolution of 1

70、0ms</p><p>　　Synchronization via serid communication via LAN or local</p><p>　　? Redundancy</p><p>　　Voting and change-over for redundant processing and communication elements of th

71、e own automation unit</p><p>　　Supports voting and change-over by an external SCA-RS redundancy switch</p><p>　　Supports applicational voting and change-over by an external system,e.g.a control

72、system</p><p>　　? SAT TOLLBOX|| connection</p><p>　　Storing firmware and parameters on a Flash Card</p><p>　　Communication:</p><p>　　? Communication via installable pro

73、tocol elements to any superior or subordinate automation unit</p><p>　　? Automatic data flow routing</p><p>　　? Priority based data transmission (priority control)</p><p>　　? Own ci

74、rcular buffer and process image for each connected station(data keeping)</p><p>　　? Redundant communication routes</p><p>　　Communication with redundant remote stations</p><p>　　? S

75、pecial application specific functions for dial-up traffic</p><p>　　Test if stations are reachable</p><p>　　Process Peripherals:</p><p>　　? Transmission of spontaneous information ob

76、jects from and to peripheral elements, via the serial Ax 1703 peripheral bus</p><p>　　Functions for Automation:</p><p>　　? Open-/closed-loop control function for the execution of freely definabl

77、e user programs which are created with CAEX plus according to IEC 61131-3,e.g.using function diagram technology</p><p>　　512KB for user program </p><p>　　Approx 50.000 variables and signals,2.00

78、0 of them retained</p><p>　　Cycle of 10ms or a multiple thereof</p><p>　　Online test</p><p>　　Loadable without service interruption</p><p>　　? Redundant open-/closed-lo

79、op control functions</p><p>　　Synchronization via redundancy link</p><p>　　Transmission of periodic process information between the open-/closed-loop control function and the peripheral elements

80、,via the serial Ax 1703 peripheral bus.</p><p>　　Six、SIEMENS PLC </p><p>　　SIMATIC S7-300 series PLC applied to all walks of life and various occasions in the detection, monitoring and control o

81、f automation, its power to both the independent operation of, or connected to a network able to achieve complex control. </p><p>　　The photoelectric products with isolation, high electromagnetic compatibilit

82、y; have high industrial applicability, allowing the ambient temperature of 60 ℃; has strong anti-jamming and anti-vibration and impact resistance, so in a harsh working environment has been widely Applications. </p>

83、;<p>　　I also mean freedom of communication S7-300 type PLC' s a very unique feature, which allows S7-300-PLC can deal openly with any other communications equipment, communications controller, or PLC S7-300 t

84、ype can be defined by the user's own Communications protocol (of the agreement ASCII), the baud rate to 1.5 Mbit / s (adjustable). So that can greatly increase the scope of communications so that the control system c

85、onfiguration more flexible and convenient. Of any kind with a serial interface per</p><p>　　When the PC offline, under the control of the next crew, the whole system can operate normally. </p><p&g

86、t;　　PC that is by control centre, mainly by the PC and laser printer components, using SIMATIC WINCC software platform, the all-Chinese interface, friendly man-machine dialogue. Managers and operators can be observed thr

87、ough a PC, shown in the various kinds of information to understand the present and pion tasks. </p><p>　　WINCC and the ice-storage operation of the automatic control system and all the parameters, and throug

88、h the mouse to print equipment management and implement at software in the field of automation can be used for all the operators’ control and monitoring tasks. Can be controlled in the process of the events clearly show,

89、 and shows the current status and order records, the recorded data can show all or select summary form, or may be required for editing, printing and output statements and trends </p><p>　　WINCC able to contr

90、ol the critical situation in the early stages of the report, and the signal can be displayed on the screen, can also use sound to be felt. It supported by online help and operational guidelines to eliminate failure. WINC

91、C a workstation can be devoted to the process control to the process so that important information not is shielded. Software-assisted operation strategy ensures that the process was not illegal to visit and to provide fo

92、r non-industrial environment in the wrong</p><p>　　WINCC is MICRSOFT WINDOWS98 or WINDOWS NT4.0 operating system, running on a PC object-oriented class 32-bit applications, OLE through the window and ODBC st

93、andard mechanism, as an ideal partner to enter the communications world WINDOWS, it can be easily WINCC To integrate a company-wide data processing system. </p><p>　　Seven、Communications</p><p>

94、　　Communications are vital to an individual automation cell and to the automated factory as a whole. We've heard a lot about MAP in the last few years, and a lot of companies have jumped on the band wagon. Many, howe

95、ver were disappointed when a fully-defined and completed MAP specification didn’t appear immediately. Says Larry Kumara:”Right now , MAP is still a moving target for the manufacturers specification that is not final. Pre

96、sently, for example, people are introducing products to meet the M</p><p>　　Because of this, many PLC vendors are holding off on full MAP implementations. Omron, for example has an ongoing MAP-compatibility

97、program, but Frank Newborn, vice president of Omron’s Industrial Division, reports that because of the lack of a firm definition, Omron's PLCs don't yet talk to MAP.</p><p>　　Since it’s unlikely that

98、 an individual PLC would talk to broadband MAP anyway, makers are concentrating n proprietary networks. According to Sal Provanzano, users fear that if they do get on board and vendors withdraw from MAP, they ‘ll pulse w

99、idth modulation control system be the ones left holding a communications structure that’s not supported.</p><p><b>　　一、PLC概述</b></p><p>　　可編程控制器是60年代末在美國(guó)首先出現(xiàn)的，當(dāng)時(shí)叫可編程邏輯控制器PLC（Programm