外文翻譯--plc控制系統(tǒng)設計的要點

1、<p>　　Plc control system design elements</p><p>　　Originally, the PLC was represented by the acronym PC. There was some confusion with using this acronym as it is commonly accepted to represent personal

2、 computer. Therefore, PLC is now commonly accepted to mean programmable logic contoller.</p><p>　　A PLC is a user-friendly, microprocessor-based specialized computer that carries out control functions of ma

3、ny types and leves of complexity. Its purpose is to monitor crucial process parameters and adjust process operations accordingly. It can be programmed, controlled, and operated by a person unskilled in operating computer

4、. Essentially, a PLC’s operator draws the lines and devices of ladder diagrams with a keyboard onto a display screen. The resulting drawing is converted into computer mach</p><p>　　The computer takes the pla

5、ce of much of the external wiring required for control of a process. The PLC will operate any system that has output devices that go on and off (known as discrete, or digital, outputs). It can also operate any system wit

6、h variable (analog) outputs. The PLC can be operated on the input side by on-off devices (discrete, or digital) or by variable (analog) input devices.</p><p>　　Today, the big unit growth in the PLC industy i

7、s at the low end-where small keeps getting smaller. When a few years ago the micro PLC entered the market, some thougt that these devices had “bottomed out”. Now,nano PLCs-generally defined as those with 16 or fewer I/O-

8、are spreading. Some can fit into your shirt pocket, being no larger than a deck of cards and at the time of this writing, PLC Direct plants to introduce a PLC the size of a box of Tic-Tac candy that will include many fea

9、tures of curr</p><p>　　The first PLC systems evolved from conventional computers in the late 1960s and early 1970s. These first PLCs were installed primarily in automotive plants. Traditionally, The auto pl

10、ants had to be shut down for up to a month at model changeover time. The early PLCs were used along with other new automation techniques to shorten the changeover time. One of the major time-consuming changeover procedur

11、es had been the wiring of new or revised relay and control panels. The PLC keyboard reprogrammin</p><p>　　There was a major problem with these early 1970s computer/PLC reprogramming procedures. The programs

12、were complicated and required a highly trained programmer to make the changes. Through the late 1970s, improvements were made in PLC programs to make them somewhat more user friendly; in 1978, the introduction of the mic

13、roprocessor chip increased computer power for all kinds of automotion systems and lowered the computing cost. Robotics, automotion devices, and computers of all types, including t</p><p>　　In the 1980s, with

14、 more computer power per dollar available, the PLC came into exponentially increasing use. Some large electronics and computer companies and some diverse corporate electronics divisions found that the PLC had become thei

15、r greatest volume product. The market for PLCs grew from a volume of $80 million in 1978 to $1 billion per year by 1990 and is still growing. Even the machine tool industry, where compute numerical controls (CNCs) have b

16、een used in the past, is using PLCs. PLCs </p><p>　　A person knowledgeable in relay logic systems can master the major PLC functions in a few hours, These functions might include coils, contacts, timers and

17、counters. The same is true for a person with a digital logic background. For persons unfamiliar with ladder diagrams or digital principles, howere, the learning process takes more time.</p><p>　　A person kno

18、wledgeable in relay logic can master advanced PLC functions in a few days with proper instruction. Company schools and operating manuals are very helpful in mastering these advanced functions. Advanced functions in order

19、 of learning might include sequence/drum controller, register bit use, and more functions.</p><p>　　Following are 8 major advantages of using a programmable controller.</p><p>　?、貴lexibility. In

20、 the past, each different electronically controlled production machine required own controller; 15 machines might require 15 different controllers. Now it is possible to use just one model of a PLC to run any one of the

21、15 machines. </p><p>　?、贗mplementing Change and Correcting Errors. With a wired relay-type panel, any program alterations require time for rewriting of panels and devices. When a PLC program circuit or seque

22、nce design change is made, the PLC program can be changed from a keyboard sequence in a metter of minutes. No rewiring is required for a PLC-controlled system.</p><p>　?、跮arge quantities of contacts. The PLC

23、 has a large number of contacts for each coil available in its programming.suppose that a panel-wired relay has four contacts and all are in use when a design change requiring three more contacts is made. Time would have

24、 to be taken to procure and install a new relay or relay contact block. Using a PLC, howere, only three more contacts would be typed in. the three contact would be automatically available in the PLC. Indeed, a hundred co

25、ntacts can be used fro</p><p>　?、躄ower cost. Increased technology makes it possible to condense more functions into smaller and less expensive packages. Now you can purchase a PLC with numerous relays, timer

26、s and counters, a sequencer, and other function for a few hundred dollars.</p><p>　?、軵ilot Running. A PLC programmed circuit can be evaluated in the office or lab. The program can be typed in, tested, observ

27、ed, and modified if needed, saving valuable factory time. In contrast, conventional relay systems have been tested on the factory floor, which can be very time consuming.</p><p>　　⑥Visual Observation. A PLC

28、circuit’s operation can be seen during operation directly on a CRT screen. The operation or misoperation of a circuit can be observed as it happens. Logic paths light up on the screen as they are energized. Troubleshooti

29、ng can be done more quickly during visual observation. In advanced PLC systems, an operator message can be programmed for each possible malfunction.</p><p>　　In advanced PLC systems, an operator message can

30、be programmed for each possible malfunction. The malfunction description appears on the screen when the malfunction is detected by the PLC logic. Advanced PLC systems also may have descriptions of the function of each ci

31、rcuit component. </p><p>　?、逽peed of Operation. Relays can take an unacceptable amount of time to actuate. The operational speed for the PLC program is very fast. The speed for the PLC logic operation is det

32、ermined by scan time, which is a matter of milliseconds.</p><p>　?、郘adder or Boolean Programming Method. The PLC programming can be accomplished in the ladder mode by an electrician or technician. Alternativ

33、ely, a PLC programmer who works in digital or Boolean control systems can also easily perform PLC programming.</p><p>　　In modern industrial production equipment, and large numbers of simulations of the cont

34、rol devices, such as the cease electrical, electromagnetic devices to turn, the number of products, temperature, Ap power, and set the flow control, the automatic control of the industrial site, If a programmable control

35、ler (PLC) to resolve the issue has become a cybernetic one of the most effective tools, this article describes Plc control system design should be noted. Hardware purchase many products current</p><p>　　Firs

36、t, the system should first determine the size of single control system with Plc or using Plc networking, thus calculating Plc importing, exporting. Few, and in some Plc to be in real need have a certain cushion</p>

37、<p>　　Second, determine the type of load under Plc export-led type of load is the DC or exchange-type, big or small currents, and Plc export points such as the frequency of movements, the use of relays to determin

38、e export-export, or transistor output, or goods of export gates. Different load choose different ways to export to the operating system's stability is very important.</p><p>　　Third, the storage capacity

39、 and speed while foreign manufacturers of Plc products essentially the same, but there are some differences. Currently the company has not yet found full compatibility between products. The development of software compan

40、ies are not the same, and users of storage capacity and procedures to implement the Directive speed are two important indicators. General greater storage capacity, faster speed on the Plc higher prices, but should be bas

41、ed on system size reasonable choi</p><p>　　Fourth, programming devices Plc programming can purchase three ways : Using hand-held programming device programming in general, it can provide businesses phrases

42、 programming language table. This approach inefficient, but the capacity of small systems, the products more suitable for small consumption, and small size, ease of debugging scene, but also lower costs. Using graphical

43、programming device programming, the programming device used Trapezoid Chart programming for visual and general elect</p><p>　　Fifth, And large companies to choose their quality guaranteed products, and good

44、technical support, after sales services are generally better, but also help expand your product and software upgrades.</p><p>　　For small systems, such as 80 points within the system. Generally do not need e

45、xpansion; When a larger system, we must expand. Different companies products to the total points system and the expansion of the number of modules have limitations when expansion can not meet the requirements, can networ

46、k structure; At the same time, some manufacturers of individual products do not support the expansion module directives, in software development, we must pay attention to. When using such simulation mo</p><p&g

47、t;　　When using a Plc network design, its much more difficult to control than single Plc. First you should choose their own more familiar type, its basic instructions and a more in-depth understanding of the functional co

48、mmands, and the speed and direction of the implementation of storage capacity users should also be careful about the procedure. Otherwise, you can not adapt to the real-time requirements, resulting in the collapse of the

49、 system. In addition to communications interfaces, communication</p><p>　　In the preparation of the software, should first become familiar with the use of Plc software products specification, the question sk

50、illed later programming. If using graphical programming device or software package programming may direct programming, if using hand-held programming device programming, should be painted Trapezoid Chart before programmi

51、ng, so can less mistakes speed was fast. After the first air conditioning programming procedures to be normal functioning of all, again in equipmen</p><p>　　PLC控制系統(tǒng)設計的要點</p><p>　　可編程序控制器 (可設計的控制

52、器) 本來應簡稱個人計算機，為了與個人計算機的簡稱個人計算機相區(qū)別,一般將它簡稱為 PLC(可設計的邏輯控制器)。</p><p>　　PLC 是一個方便使用，是實行許多類型和復雜層的控制功能的基于微處理器的特殊計算機. 它的目的是適當?shù)貦z測決定性的程序叁數(shù)并且調(diào)整程序操作。在操作計算機方面不熟練的人能對它進行規(guī)劃，控制, 而且操作。 本質(zhì)上, 一個 PLC 的操作員在一個展覽熒屏之上用一個鍵盤畫梯圖表的線和裝置

53、. 產(chǎn)生的圖畫轉(zhuǎn)換成計算機機器語言和作為一個用戶程序運行。</p><p>　　計算機代替了一個過程控制所需的許多外部配線。 PLC 將會操作有開或關的輸出裝置的任何系統(tǒng) (已知不連續(xù)的，或數(shù)字的, 輸出) 。 它也能操作任何輸出為變量 (模擬) 的系統(tǒng). PLC 能通過開關裝置 (不連續(xù)的, 或數(shù)字的) 或輸入變量 (模擬) 的裝置在輸入端進行操作。</p><p>　　今天, 在PLC

54、工業(yè)中的大單位增長就要結(jié)束-因為小的變得越來越小。 微 PLC 數(shù)年以前進入了市場，一些人認為這些裝置"降到最低點"。 現(xiàn)在,十億分之一 PLCs-通常定義了 16 或者較少的輸入／輸出-正在廣泛應用。 一些能裝在你的襯衫口袋，沒有一副卡片大并且能在任何時間寫作, 引入的 PLC 將會包括現(xiàn)在微模型的許多特征,它只有Tic-Tac 的糖果盒子的大小。</p><p>　　在 1960 年代后期

55、和 1970 年代早期內(nèi)從傳統(tǒng)的計算機進展而來的第一個 PLC 系統(tǒng)。這些 PLCs 主要安裝在汽車的植物中。 傳統(tǒng)地, 在樣板的轉(zhuǎn)換時間汽車廠必須停工一個月。 早的 PLCs 連同其他的新自動化技術(shù)的使用縮短了轉(zhuǎn)換時間。 主要耗時的轉(zhuǎn)換程序之一已經(jīng)是新的配線或者校訂了的繼電器和控制嵌板。重新規(guī)劃程序的 PLC 鍵盤代替了大量電線，繼電器, 定時器的配線和其他的元件.新的PLC 讓轉(zhuǎn)換時間變成大約幾天。</p><p

56、>　　這些 1970 年代早期的重新規(guī)劃程序的計算機/PLC有一個主要問題。 編程是復雜的而且需要一個高度訓練的程序師來修改。 1970 年代后期, PLC 編程的改進使用其成為更方便的使用；在 1978 年，微處理器片的引進為各種的自動化 系統(tǒng)增加了計算機能力而且降低計算機費用。 所有類型的機器人，自動化 裝置和計算機，包括 PLC, 都有了許多進步 。PLC的高級語言編程，對較多的人變得更可以理解了, 而且PLCs 成為能買

57、的起的。</p><p>　　在 1980 年代中，隨著計算機價位的變化, PLC 的使用指數(shù)逐漸增加。 一些大的電子學和計算機公司和一些不同的企業(yè)電子學機構(gòu)發(fā)現(xiàn) PLC 已經(jīng)成為他們最好銷售量的產(chǎn)品。 PLC的市場已經(jīng)從1978 年八千萬元開始到1990年以每年十億元的幅度增長而且仍然正在增加。 甚至過去使用數(shù)控技術(shù)的機械制造工業(yè), 也正在使用 PLCs。PLCs 也廣泛地被用于建立能源和安全控制制系統(tǒng)。PL

58、C在家用產(chǎn)品和醫(yī)療器材中的非傳統(tǒng)使用已經(jīng)在 1990 年代出現(xiàn)暴長,而且在我們進入新的千年將繼續(xù)增長。</p><p>　　一個在繼電器邏輯系統(tǒng)方面有豐富知識的人,能在很短的時間內(nèi)掌握主要的 PLC 功能, 這些功能可能包括盤繞卷，接觸器，定時器和計數(shù)器。 對有著數(shù)字邏輯背景的人也是同樣的。 因為不熟悉梯圖表或數(shù)字原則的人， 卻要花較多的時間去學習。</p><p>　　一個有豐富繼電器邏

59、輯知識的人,在幾天之內(nèi),通過適當?shù)闹笇Ь湍苷莆障冗M的 PLC 功能。 學校和操作手冊在掌握這些先進的功能方面非常有幫助。 在學習的次序中,先進的功能可能包括序列/ 控制器，寄存器位使用。</p><p>　　以下是使用一個可編程控制器的 8 個主要優(yōu)點。</p><p>　?、購姷倪m應性。 過去, 每個不同的電子受約束的生產(chǎn)機器需要自己的控制器；15 部機器可能需要 15 個不同的控制器。

60、 現(xiàn)在只是使用 PLC 的一個模型就可以運行 15 部機器中任何一個。 </p><p>　?、趯崿F(xiàn)變化和改正錯誤。 當使用線路繼電器面板時, 任何的程序改變需要面板和裝置的重寫時間。 當改變一個 PLC 編程線路或序列設計的時候, PLC 編程能在數(shù)分鐘內(nèi)從鍵盤序列中改變。一個 PLC 控制系統(tǒng)不需要重新配線。</p><p>　?、鄞罅康慕佑|器。 PLC有很多的接觸器，假設一個面板線路

61、繼電器有四個觸點,當一個設計需要三個或以上觸點時,所有的都被用了。 有需要花時間去設計和安裝新的繼電器和繼電器觸點. 使用 PLC ，不過只有三個多觸點。三個觸點會自動地在 PLC 中獲得。 的確, 從一個繼電器上可獲得一百個觸點-如果計算機有足夠大的內(nèi)存。</p><p>　　④降低費用。 增加的技術(shù)濃縮較多的功能為較小的和不貴的包。 現(xiàn)在用不多于一百元就能買到有許多繼電器,定時器,控制柜，程控裝置和其它的功能

62、的PLC。</p><p>　　⑤容易調(diào)試。編程后的PLC能在辦公室或?qū)嶒炇冶辉u估。 程序能被打印，測試，觀察，而且如果需要可以修正, 節(jié)約了工廠的時間。 相反的，傳統(tǒng)的繼電器系統(tǒng)只能在工廠測試, 這可能是最時間消耗。</p><p>　　⑥可觀察性. 在CRT熒屏上可以直接看到PLC的電路運行。 電路的運行或運行不當能被觀察到。當他們被激活時，邏輯路徑在熒屏上顯示。 故障修理能被更快在視

63、覺的觀察期間完成。</p><p>　　先進的 PLC 系統(tǒng), 對于每個可能的故障都能描述其操作信息。當故障被 PLC 邏輯發(fā)現(xiàn)的時候，故障描述在熒屏上出現(xiàn)。 先進的 PLC 系統(tǒng)也可能有每個線路元件的功能描述。</p><p>　?、咚俣? 繼電器可能花無法接受的時間達到精確 。PLC 程序的操作速度是非常快的.PLC邏輯運行的速度由掃描時間決定, 它按毫秒計算。</p>

64、<p>　　⑧梯型圖和布爾編程方法。 PLC 編程被一個電學家或技術(shù)人員在梯型圖中完成。 二者擇一, 一個數(shù)字或者布爾控制系統(tǒng)的 PLC 程序師也能容易地編寫PLC 程序。</p><p>　　在現(xiàn)代化的工業(yè)生產(chǎn)設備中，有大量的數(shù)字量及模擬量的控制裝置，例如電機的起停，電磁閥的開閉，產(chǎn)品的計數(shù)，溫度、壓力、流量的設定與控制等，工業(yè)現(xiàn)場中的這些自動控制問題，若采用可編程序控制器（PLC）來解決自動控制問題

65、已成為最有效的工具之一，本文敘述PLC控制系統(tǒng)設計時應該注意的問題。硬件選購目前市場上的PLC產(chǎn)品眾多，除國產(chǎn)品牌外，國外有：日本的 OMRON、MITSUBISHI、FUJJ、ANASONIC, 德國的SIEMENS，韓國的LG等。近幾年，PLC產(chǎn)品的價格有較大的下降，其性價比越來越高，這是眾多技術(shù)人員選用PLC的重要原因。那么，如何選購PLC產(chǎn)品呢? ①系統(tǒng)規(guī)模首先應確定系統(tǒng)用PLC單機控制，還是用PLC形成網(wǎng)絡，由此計算P