可編程序控制器畢業(yè)論文外文文獻(xiàn)翻譯

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1、 英語原文： Programmable logic controller A programmable logic controller (PLC) or simply programmable controller is a digital computer used for automation of industrial processes, such as control of machinery on factory assembly lines. Unlike general-purpose computers, the PLC is designed for multiple

2、 inputs and output arrangements, extended temperature ranges, immunity to electrical noise, and resistance to vibration and impact. Programs to control machine operation are typically stored in battery-backed or non-volatile memory. A PLC is an example of a real time system since output results must

3、 be produced in response to input conditions within a bounded time, otherwise unintended operation will result.. Features The main difference from other computers is that PLC are armored for severe condition (dust, moisture, heat, cold, etc) and have the facility for extensive input/output (I/O) a

4、rrangements. These connect the PLC to sensors and actuators. PLC read limit switches, analog process variables (such as temperature and pressure), and the positions of complex positioning systems. Some even use machine vision. On the actuator side, PLC operate electric motors, pneumatic or hydraulic

5、 cylinders, magnetic relays or solenoids, or analog outputs. The input/output arrangements may be built into a simple PLC, or the PLC may have external I/O modules attached to a computer network that plugs into the PLC. PLC were invented as replacements for automated systems that would use hundreds

6、 or thousands of relays, cam timers, and drum sequencers. Often, a single PLC can be programmed to replace thousands of relays. Programmable controllers were initially adopted by the automotive manufacturing industry, where software revision replaced the re-wiring of hard-wired control panels when p

7、roduction models changed. Many of the earliest PLC expressed all decision making logic in simple ladder logic which appeared similar to electrical schematic diagrams. The electricians were quite able to trace out circuit problems with schematic diagrams using ladder logic. This program notation was

8、 chosen to reduce training demands for the existing technicians. Other early PLC used a form of instruction list programming, based on a stack-based logic solver. The functionality of the PLC has evolved over the years to include sequential relay control, motion control, process control, distribute

9、d control systems and networking. The data handling, storage, processing power and communication capabilities of some modern PLC are approximately equivalent to desktop computers. PLC-like programming combined with remote I/O hardware, allow a general-purpose desktop computer to overlap some PLC in

10、certain applications. PLC compared with other control systems PLC are well-adapted to a range of automation tasks. These are typically industrial processes in manufacturing where the cost of developing and maintaining the automation system is high relative to the total cost of the automation, and

11、where changes to the system would be expected during its operational life. PLC contain input and output devices compatible with industrial pilot devices and controls; little electrical design is required, and the design problem centers on expressing the desired sequence of operations in ladder logic

12、 notation. PLC applications are typically highly customized systems so the cost of a packaged PLC is low compared to the cost of a specific custom-built controller design. On the other hand, in the case of mass-produced goods, customized control systems are economic due to the lower cost of the comp

13、onents, which can be optimally chosen instead of a "generic" solution, and where the non-recurring engineering charges are spread over thousands of places. For high volume or very simple fixed automation tasks, different techniques are used. For example, a consumer dishwasher would be controlled by

14、 an electromechanical cam timer costing only a few dollars in production quantities. A microcontroller-based design would be appropriate where hundreds or thousands of units will be produced and so the development cost (design of power supplies and input/output hardware) can be spread over many sal

15、es, and where the end-user would not need to alter the control. Automotive applications are an example; millions of units are built each year, and very few end-users alter the programming of these controllers. However, some specialty vehicles such as transit busses economically use PLC instead of cu

16、stom-designed controls, because the volumes are low and the development cost would be uneconomic. Very complex process control, such as used in the chemical industry, may require algorithms and performance beyond the capability of even high-performance PLC. Very high-speed or precision controls may

17、 also require customized solutions; for example, aircraft flight controls. PLC may include logic for single-variable feedback analog control loop, a "proportional, integral, derivative" or "PID controller." A PID loop could be used to control the temperature of a manufacturing process, for example.

18、 Historically PLC were usually configured with only a few analog control loops; where processes required hundreds or thousands of loops, a distributed control system (DCS) would instead be used. However, as PLC have become more powerful, the boundary between DCS and PLC applications has become less

19、clear-cut. Digital and analog signals Digital or discrete signals behave as binary switches, yielding simply an On or Off signal (1 or 0, True or False, respectively). Push buttons, limit switches, and photoelectric sensors are examples of devices providing a discrete signal. Discrete signals are

20、sent using either voltage or current, where a specific range is designated as On and another as Off. For example, a PLC might use 24 V DC I/O, with values above 22 V DC representing On, values below 2VDC representing Off, and intermediate values undefined. Initially, PLC had only discrete I/O. Anal

21、og signals are like volume controls, with a range of values between zero and full-scale. These are typically interpreted as integer values (counts) by the PLC, with various ranges of accuracy depending on the device and the number of bits available to store the data. As PLC typically use 16-bit sign

22、ed binary processors, the integer values are limited between -32,768 and +32,767. Pressure, temperature, flow, and weight are often represented by analog signals. Analog signals can use voltage or current with a magnitude proportional to the value of the process signal. For example, an analog 4-20 m

23、 or 0 - 10?V input would be converted into an integer value of 0-32767. Current inputs are less sensitive to electrical noise (i.e. from welders or electric motor starts) than voltage inputs. System scale A small PLC will have a fixed number of connections built in for inputs and outputs. Typical

24、ly, expansions are available if the base model does not have enough I/O. Modular PLC have a chassis (also called a rack) into which is placed modules with different functions. The processor and selection of I/O modules is custom for the particular application. Several racks can be administered by a

25、 single processor, and may have thousands of inputs and outputs. A special high speed serial I/O link is used so that racks can be distributed away from the processor, reducing the wiring costs for large plants. PLC used in larger I/O systems may have peer-to-peer (P2P) communication between proces

26、sors. This allows separate parts of a complex process to have individual control while allowing the subsystems to co-ordinate over the communication link. These communication links are also often used for HMI (Human-Machine Interface) devices such as keypads or PC-type workstations. Some of today's

27、PLC can communicate over a wide range of media including RS-485, Coaxial, and even Ethernet for I/O control at network speeds up to 100m. Programming Early PLC, up to the mid-1980s, were programmed using proprietary programming panels or special-purpose programming terminals, which often had dedic

28、ated function keys representing the various logical elements of PLC programs. Programs were stored on cassette tape cartridges. Facilities for printing and documentation were very minimal due to lack of memory capacity. More recently, PLC programs are typically written in a special application on a

29、personal computer, then downloaded by a direct-connection cable or over a network to the PLC. The very oldest PLC used non-volatile magnetic core memory but now the program is stored in the PLC either in battery-backed-up RAM or some other non-volatile flash memory. Early PLC were designed to repla

30、ce relay logic systems. These PLC were programmed in "ladder logic", which strongly resembles a schematic diagram of relay logic. Modern PLC can be programmed in a variety of ways, from ladder logic to more traditional programming languages such as BASIC and C. Another method is State Logic, a Very

31、High Level Programming Language designed to program PLC based on State Transition Diagrams. Recently, the International standard IEC 61131-3 has become popular. IEC 61131-3 currently defines five programming languages for programmable control systems: FBD (Function block diagram), LD (Ladder diagra

32、m), ST (Structured text, similar to the Pascal programming language), IL (Instruction list, similar to assembly language) and SFC (Sequential function chart). These techniques emphasize logical organization of operations. While the fundamental concepts of PLC programming are common to all manufactu

33、rers, differences in I/O addressing, memory organization and instruction sets mean that PLC programs are never perfectly interchangeable between different makers. Even within the same product line of a single manufacturer, different models may not be directly compatible. User interface PLC may nee

34、d to interact with people for the purpose of configuration, alarm reporting or everyday control. A Human-Machine Interface (HMI) is employed for this purpose. HMI' are also referred to as MMI' (Man Machine Interface) and GUI (Graphical User Interface). A simple system may use buttons and lights to

35、interact with the user. Text displays are available as well as graphical touch screens. Most modern PLC can communicate over a network to some other system, such as a computer running a SCADA (Supervisory Control And Data Acquisition) system or web browser. Communications PLC usually have built in

36、 communications ports usually 9-Pin RS232, and optionally for RS485 and Ethernet. DF1 is usually included as one of the communications protocols. Other communications protocols that may be used are listed in the List of automation protocols. History The PLC was invented in response to the needs of

37、 the American automotive industry. Before the PLC, control, sequencing, and safety interlock logic for manufacturing automobiles was accomplished using relays, timers and dedicated closed-loop controllers. The process for updating such facilities for the yearly model change-over was very time consum

38、ing and expensive, as the relay systems needed to be rewired by skilled electricians. In 1968 GM Hydra (the automatic transmission division of General Motors) issued a request for proposal for an electronic replacement for hard-wired relay systems. The winning proposal came from Bedford Associates

39、of Bedford, Massachusetts. The first PLC, designated the 084 because it was Bedford Associates' eighty-fourth project, was the result. Bedford Associates started a new company dedicated to developing, manufacturing, selling, and servicing this new product: Mod, which stood for One of the people who

40、worked on that project was Dick Morley, who is considered to be the "father" of the PLC. The brand was sold in 1977 to Gould Electronics, and later acquired by German Company AEG and then by French Schneider Electric, the current owner. One of the very first 084 models built is now on display at he

41、adquarters in North Andover, Massachusetts. It was presented to by GM, when the unit was retired after nearly twenty years of uninterrupted service. The automotive industry is still one of the largest users of PLC, and still numbers some of its controller models such that they end with eighty-four.

42、 PLC are used in many different industries and machines such as packaging and semiconductor machines. Well known PLC brands are Toshiba, Siemens, Allen-Bradley, ABB, Mitsubishi, Omron, and General Electri. 附錄 B 英語翻譯： 可編程序控制器 可編程邏輯控制器(PLC)或干脆可編程序控制器是一個數(shù)字化的計(jì)算機(jī)

43、用于自動化的工業(yè)生產(chǎn)過程，如控制機(jī)械的工廠裝配生產(chǎn)線。不同于一般用途的電腦，臨立會是專為多重輸入和輸出的安排，延長工作溫度范圍，免疫力電氣噪聲，抗振動和影響。程式控制機(jī)器操作通常存儲在備用電池或非揮發(fā)性記憶體。PLC的便是一個例子，一個實(shí)時系統(tǒng)的輸出結(jié)果，因?yàn)楸仨毘鍪驹诨貞?yīng)輸入條件，在一個范圍內(nèi)的時間，否則意想不到的行動將導(dǎo)致.. 特征 主要區(qū)別從其他電腦上是PLC的是裝甲嚴(yán)重條件(灰塵，潮濕，熱源，冷等)，并有設(shè)施，廣泛的輸入/輸出(I/O)的安排。這些連接PLC在傳感器和致動器。PLC的閱讀限位開關(guān)，模擬過程變量(如溫度和壓力)，以及立場復(fù)雜的定位系統(tǒng)。有的甚至使用機(jī)器視覺。對

44、致動器方面，PLC的運(yùn)作，電機(jī)，氣動或液壓缸，磁繼電器或螺線管，或模擬輸出。輸入/輸出的安排，可能建成一個簡單的PLC，或臨立會可能有外部I/O模塊連接到一個計(jì)算機(jī)網(wǎng)絡(luò)，插入PLC。 PLC的發(fā)明替代的自動化系統(tǒng)將使用數(shù)百或數(shù)千繼電器，凸輪定時器，和鼓時序。很多時候，一個單一的可編程控制器可以編程，以取代數(shù)以千計(jì)的繼電器?？删幊炭刂破髯畛跛ㄟ^的汽車制造業(yè)，軟件修訂取代了重新布線的硬連線控制面板，當(dāng)生產(chǎn)模式改變。 很多最早的PLC表示，所有的決策邏輯，在簡單邏輯的階梯，出現(xiàn)類似的電氣示意圖。該電工是相當(dāng)能追查出電路的問題與示意圖使用階梯邏輯。這個程式符號選擇，以減少培訓(xùn)

45、的要求，對于現(xiàn)有的技術(shù)人才。其他早期的PLC使用的一種形式，教學(xué)名單編程的基礎(chǔ)上，堆棧為基礎(chǔ)的邏輯求解。 功能的PLC已多年的發(fā)展，包括序貫繼電器控制，運(yùn)動控制，過程控制，分布式控制系統(tǒng)和網(wǎng)絡(luò)。數(shù)據(jù)處理，儲存，加工能力和通信能力，一些現(xiàn)代的PLC是約相當(dāng)于臺式電腦。PLC的編程一樣，結(jié)合遠(yuǎn)程I/O的硬件，讓一般用途的臺式電腦相重疊的一些PLC在某些應(yīng)用。 PLC的比較，與其他控制系統(tǒng) PLC的良好適應(yīng)了一系列自動化的任務(wù)。這些都是典型的工業(yè)工序，在哪里制造的開發(fā)成本和維護(hù)自動化系統(tǒng)是高相對的總成本的自動化，并在變化，該系統(tǒng)預(yù)計(jì)將在其運(yùn)行壽命。PLC的控制輸入和輸出設(shè)備兼容的工業(yè)試驗(yàn)裝置

46、和控制;很少電氣設(shè)計(jì)要求，并設(shè)計(jì)問題為中心的表達(dá)理想序列的行動在階梯邏輯符號。 PLC的應(yīng)用通常是高度客制化的系統(tǒng)，使成本包裝的PLC是比較低的成本，一個具體的自訂內(nèi)建控制器的設(shè)計(jì)。在另一方面，在如此大規(guī)模生產(chǎn)的貨物，自定義的控制系統(tǒng)是經(jīng)濟(jì)，由于成本較低的元件，而最佳的選擇而不是一個“通用”的解決方案，并在非經(jīng)常性工程費(fèi)用遍布數(shù)以千計(jì)的地方。 高音量或很簡單的固定自動化的任務(wù)，不同的技術(shù)使用。舉例來說，消費(fèi)者洗碗機(jī)將控制機(jī)電凸輪計(jì)時器的成本只有幾塊錢，在生產(chǎn)數(shù)量。 1基于微控制器的設(shè)計(jì)將是適當(dāng)?shù)那闆r下數(shù)百或數(shù)千單位將制作等，開發(fā)成本(設(shè)計(jì)電源供應(yīng)器及輸入/輸出硬件)，可以傳播很多

47、的銷售，并在最終用戶不會需要改變控制。汽車應(yīng)用的一個例子;百萬計(jì)的單位，每年興建，只有極少數(shù)的最終用戶改變編程這些控制器。然而，一些專業(yè)車輛，如過境客，在經(jīng)濟(jì)上使用的PLC不是定制設(shè)計(jì)的控制，因?yàn)榱康?，開發(fā)成本將是不經(jīng)濟(jì)。非常復(fù)雜的過程控制，如用在化學(xué)工業(yè)中，可能需要算法和性能超越的能力，甚至性能高的PLC。非常高的速度和精確度的控制可能還需要定制的解決方案;舉例來說，飛機(jī)的飛行管制。 臨立會可能包括邏輯單變量反饋的模擬控制回路，“比例，積分，導(dǎo)數(shù)”或“ PID控制”。1PID控制回路可用于控制溫度的制造過程，例如。歷史上的PLC通常配置，只有少數(shù)的模擬控制回路;何處過程中所需的數(shù)

48、百或數(shù)千循環(huán)，分布式控制系統(tǒng)(DCS)反而會使用。不過，由于臨立會已成為更強(qiáng)大，邊界之間的DCS與PLC的應(yīng)用已成為少，旗幟鮮明。 數(shù)字和模擬信號 數(shù)字或離散信號的表現(xiàn)，作為二進(jìn)制開關(guān)，收益率只是一個或關(guān)閉的信號(1或0，真或假，分別)。按鍵，限位開關(guān)，光電傳感器的例子裝置提供了一個離散信號。離散信號發(fā)送使用的電壓或電流，在特定范圍指定為就和另一個作為小康。舉例來說，一個PLC可能使用24伏直流電的I/O，價值觀，上述22伏直流電代表對，價值觀下面2vdc代表起飛，中間值未定義。最初，PLC的只有離散的I/O。 模擬信號一樣，音量控制，與一系列的價值觀之間的零和滿標(biāo)。

49、這些都是典型的解釋為整數(shù)的值(計(jì)數(shù))由臨立會，與各范圍的準(zhǔn)確性，根據(jù)設(shè)備和雙邊投資協(xié)定的數(shù)量可用來儲存數(shù)據(jù)。作為PLC的通常使用的16位二進(jìn)制簽署的處理器，整數(shù)的價值是有限的之間-32768和32767。壓力，溫度，流量，和重量，往往所代表的模擬信號。模擬信號可以使用的電壓或電流與規(guī)模成比例的價值的過程中的信號。 舉例來說，一個充滿模擬信號的4-20米或0-10V的輸入電壓會轉(zhuǎn)化為一個整數(shù)，值為0-32767。目前的投入是不太敏感的電氣噪聲(即由焊工或電動馬達(dá)啟動)，比電壓輸入。 編程 早期的PLC ，直至20世紀(jì)80年代中期，它當(dāng)初的程序使用專有的編程小組或特殊用途的編程終端，往往有專

50、門的功能鍵代表不同的邏輯要素的PLC程序。程序存儲在盒式磁帶匣。設(shè)施，為印刷及文件很小由于缺乏內(nèi)存容量。最近，PLC程序通常是書面處于一個特殊的應(yīng)用對一臺個人電腦，然后下載一個直接連接電纜或通過網(wǎng)絡(luò)向臨立會。非常最古老的PLC用于非揮發(fā)性記憶體磁芯，但現(xiàn)在該程序是儲存在臨立會無論是在備用電池的后續(xù)RAM或其他一些非揮發(fā)性快閃記憶體。 早期的PLC設(shè)計(jì)，以取代繼電器邏輯系統(tǒng)。這些PLC的編程人在“階梯式的邏輯”，這強(qiáng)烈類似于示意圖繼電器邏輯?，F(xiàn)代的PLC可以編程在以各種方式，從階梯的邏輯來更傳統(tǒng)的編程語言，如基本和C另一種方法是國家的邏輯，一個很高的水平編程語言設(shè)計(jì)程序基于PLC的關(guān)

51、于國家過渡的圖表。 最近，國際標(biāo)準(zhǔn)IEC 61131-3已成為受歡迎的。目前的IEC 61131-3定義5編程語言的可編程控制系統(tǒng)：森林生物多樣性(功能框圖)，勞工處(梯形圖)，圣(結(jié)構(gòu)化文本，類似該帕斯卡爾編程語言)，白細(xì)胞介素(指示列表中，類似匯編語言)和證監(jiān)會(順序功能圖)。 這些技術(shù)強(qiáng)調(diào)的邏輯組織的行動。而基本概念PLC編程是共同的所有制造商，分歧在I/O處理，記憶體的組織和指令集表示PLC程序從來都不是完全可以互換的決策者之間的不同。即使在同一產(chǎn)品線，一個單一的制造商，不同的模式未必可以直接兼容。 用戶界面 臨立會可能需要與他人互動交流為目的的配置，報(bào)警或報(bào)

52、告的日?？刂啤?1人機(jī)界面（人機(jī)界面）是受雇于作此用途。人機(jī)界面' ，也稱為的MMI(人機(jī)接口)和GUI(圖形用戶界面)。 一個簡單的系統(tǒng)可能使用按鈕和燈光的互動與用戶。文字顯示可作為以及圖形觸摸屏。最現(xiàn)代的PLC可以溝通，超過一個網(wǎng)絡(luò)，以其他一些制度，如計(jì)算機(jī)運(yùn)行的SCADA(監(jiān)控和數(shù)據(jù)采集)系統(tǒng)或Web瀏覽器。 通訊 臨立會通常有建于通信端口，通常9針的RS232，并選擇性地為RS485的和以太網(wǎng)。df1通常包括作為其中的通信協(xié)議。其他通訊協(xié)議可用于中列出的清單自動化議定書。 歷史 臨立會被發(fā)明，需要連鎖反應(yīng)，美國汽車業(yè)。之前的PLC，控制，測序，安全連鎖邏輯制

53、造的汽車是在使用繼電器，定時器和專用閉環(huán)系統(tǒng)的控制器。過程中更新等設(shè)施，每年模型變化超過十分耗費(fèi)時間和昂貴的，作為中繼系統(tǒng)需要加以rewired由熟練的電工。 在1968年通用汽車水螅(自動變速器分工，通用汽車公司)發(fā)出一份要求的建議，為電子取代硬連線中繼系統(tǒng)。 得獎的建議，來自貝德福德聯(lián)營公司的貝德福德，馬薩諸塞州。第一次臨立會，指定084，因?yàn)樗秦惖赂５翧ssociates的'80-第四個項(xiàng)目的結(jié)果。貝德福德聯(lián)營公司開始了一個新的公司，致力于開發(fā)，制造，銷售和服務(wù)這一新的產(chǎn)品：按付款當(dāng)日價格計(jì)算，其中主張之一，人民的工作，誰該項(xiàng)目迪克莫雷，誰是被視為“父親”的臨立會。品牌銷

54、售在1977年至古爾德電子，和后來收購的德國公司AEG，然后由法國施耐德電氣，目前的所有者。 其中一個很首先084的模式興建，現(xiàn)已陳列在總部在北，馬薩諸塞州。據(jù)介紹，以通用汽車，當(dāng)單位離退休經(jīng)過近二十年的服務(wù)不會中斷。 汽車業(yè)仍是其中一個最大的用戶可編程序控制器，仍然號碼它的一些控制器的模型，例如，他們最終與84。PLC的使用在許多不同的行業(yè)和機(jī)器，如包裝和半導(dǎo)體的機(jī)器。 眾所周知，PLC的品牌是東芝，西門子，艾倫-布拉德利到期，三菱，歐姆龍，和通用電氣公司。 附錄C 程序： 12