自動化專業(yè)畢業(yè)設(shè)計外文翻譯1

1、<p><b>　　外文資料</b></p><p>　　Programmable Logic Controllers (PLC), a computing device invented by Richard E. Morley in 1968, have been widely used in industry including manufacturing systems,

2、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 language visually resemb

3、ling 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 place, PLC based control will

4、 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 to a study on the PLC mar

5、ket of Frost and Sullivan [1995], an increase of the annual sales volume to 15 million PLC per year with the hardware value of more than 8 billion US dollars has been predicted, though the prices of c</p><p>

6、;　　Though PLC 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 is facing the software dil

7、emma 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 could destroy civilization.”&l

8、t;/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 costs of PLC are dropping cont

9、inuously, reducing the scan time of the ladder logic is still an issue in industry so that low-cost PLC can be used.</p><p>　　In general, the productivity in generating PLC is far behind compared to other do

10、mains, 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 software design because PLC-progr

11、amming 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 SO0/a o</p><p>

12、　　In addition, current PLC based control systems are not properly designed to support the growing demand for flexibility and reconfigure bility of manufacturing systems. A further problem, impelling the need for a system

13、atic 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 for PLC operated automatio

14、n 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, and set of design rules provi

15、ding 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>　　A systematic approach to de

16、signing PLC software can overcome deficiencies in the traditional way of programming manufacturing control systems, and can have wide ramifications in several industrial applications. Automation control systems are model

17、ed by formal languages or, equivalently, by state machines. Formal representations provide a high-level description of the behavior of the system to be controlled. State machines can be analytically evaluated as to wheth

18、er or not they meet the desired g</p><p>　　In modern manufacturing, systems are characterized by product and process innovation, become customer-driven and thus have to respond quickly to changing system req

19、uirements. A major challenge is therefore to provide enabling technologies that can economically reconfigure automation control systems in response to changing needs and new opportunities. Design and operational knowledg

20、e can be reused in real-time, therefore, giving a significant competitive edge in industrial practice.</p><p>　　Studies have shown that programming methodologies in automation systems have not been able to m

21、atch rapid increase in use of computing resources. For instance, the programming of PLC still relies on a conventional programming style with ladder logic diagrams. As a result, the delays and resources in programming ar

22、e a major stumbling stone for the progress of manufacturing industry. Testing and debugging may consume over 50% of the manpower allocated for the PLC program design. Standards have bee</p><p>　　A systematic

23、 approach will increase the level of design automation through reusing existing software components, and will provide methods to make large-scale system design manageable. Likewise, it will improve software quality and r

24、eliability and will be relevant to systems high security standards, especially those having hazardous impact on the environment such as airport control, and public railroads.</p><p>　　The software industry i

25、s regarded as a performance destructor and complexity generator. Steadily shrinking hardware prices spoils the need for software performance in terms of code optimization and efficiency. The result is that massive and le

26、ss efficient software code on one hand outpaces the gains in hardware performance on the other hand. Secondly, software proliferates into complexity of unmanageable dimensions; software redesign and maintenance-essential

27、 in modern automation systems-becomes</p><p><b>　　中文翻譯</b></p><p>　　1968年，Richard E. Morley創(chuàng)造出了新一代工業(yè)控制裝置可編程邏輯控制器(PLC),現(xiàn)在，PLC已經(jīng)被廣泛應(yīng)用于工業(yè)領(lǐng)域，包括機械制造也、運輸系統(tǒng)、化學(xué)過程設(shè)備、等許多其他領(lǐng)域。初期可編程控制器只是用一種類似于語

28、言的軟件邏輯于代替繼電器硬件邏輯，并且使開發(fā)時間由6個月縮短到6天。</p><p>　　雖然計算機控制技術(shù)已經(jīng)產(chǎn)生，但是PLC控制因為它的高性能、成本低、并且對惡劣的環(huán)境有很強的適應(yīng)能力而在工業(yè)控制的廣泛應(yīng)用中保持優(yōu)勢。而且，盡管硬件的價格在逐漸下跌，據(jù)估計，根據(jù)Frost和Sullivan對PLC市場的調(diào)查研究表明，每年銷售硬件的價格要比銷售PLC的價格（一千五百萬）至少多出八十億美元。PLC的創(chuàng)造者Rich

29、ard E. Morley十分肯定的認(rèn)為目前PLC市場是一個價值五十億的工業(yè)</p><p>　　雖然PLC廣泛應(yīng)用于工業(yè)控制中，PLC控制系統(tǒng)的程序依然和語法有關(guān)。和軟件過程一樣，PLC的軟件設(shè)計也以同樣的方式會遇到軟件錯誤或危機。Morley在演講中著重強調(diào)了這個方面。</p><p>　　如果房子建造的像軟件過程一樣，那么僅僅一只啄木鳥就可以摧毀文明。特別的，PLC程序要解決的實際問

30、題是消除軟件錯誤和減少老式梯形邏輯語言的花費。盡管PLC的硬件成本在繼續(xù)下降，但是在工業(yè)控制上減少梯形邏輯的掃描時間仍然是一個問題，以至于可以用到低耗時的PLC。</p><p>　　一般來說，和其他領(lǐng)域相比生產(chǎn)PLC的周期要短很多。例如，在實踐中，VISI設(shè)計是一種有效的計算機輔助設(shè)計。PLC不需要使用目前的以軟件設(shè)計為基礎(chǔ)軟件工程方法論，因為PLC程序要求對軟件和硬件搜都要考慮到。因此，軟件設(shè)計越來越成為花費

31、動力。在許多的工業(yè)設(shè)計工程中，超過    的人力分配給了控制系統(tǒng)設(shè)計和安裝，并且他們要對。PLC程序測試和排除錯誤，</p><p>　　再者，PLC控制系統(tǒng)不適合設(shè)計對適應(yīng)性和重構(gòu)有越來越多要求的生產(chǎn)系統(tǒng)。一個更深入的問題是在大規(guī)模的工程中軟件越來越復(fù)雜，促使要有一個系統(tǒng)化的設(shè)計方法論。</p><p>　　主題的客觀性是為PLC自動控制系統(tǒng)建立一個系統(tǒng)化的

32、軟件設(shè)計方法論。這個設(shè)計方法論包括以狀態(tài)轉(zhuǎn)換模型為基礎(chǔ)的精確的描述，這個轉(zhuǎn)臺轉(zhuǎn)換模型是自動控制系統(tǒng)的抽象系統(tǒng)。方法論還包括一個逐步的設(shè)計過程，并且要設(shè)置一個設(shè)計規(guī)則，這樣才能為一個成功的設(shè)計提供導(dǎo)向和方法。這項研究的真正目的是找到一個減少控制軟件發(fā)展過程的不穩(wěn)定性的方法，也就是說，減少程序和調(diào)試時間以及他們的變化，以增強自動控制系統(tǒng)的適應(yīng)性，并且通過調(diào)整軟件使得軟件可以再度使用。這樣的目的是為了克服目前程序策略的不足之處，而目前的程序策

33、略是以個人軟件開發(fā)者的經(jīng)驗為基礎(chǔ)的。</p><p>　　一個系統(tǒng)化的設(shè)計PLC程序的方法可以克服傳統(tǒng)程序生產(chǎn)控制系統(tǒng)的缺點，并且在一些工業(yè)應(yīng)用總有很大的不同。自動控制系統(tǒng)是狀態(tài)模型用公式語言或等價的語言描述的。公式描述對被控制的系統(tǒng)的行為提供一個精確的描述?？梢酝ㄟ^分析估計看狀態(tài)模型是否達到想要的目標(biāo)，第二，狀態(tài)模型的描述提供結(jié)構(gòu)描述，這個結(jié)構(gòu)描述可以說明邏輯要求和如細節(jié)安全規(guī)則的限制。第三，好的控制系統(tǒng)設(shè)計是

34、對自動控制代碼生成有益的——一種能夠產(chǎn)生可執(zhí)行的控制軟件的能力，不同的邏輯控制器可以減少程序掃描時間和執(zhí)行那個時間。特別的，這個主題與隨后的部分的是有關(guān)的。</p><p>　　在現(xiàn)代制造業(yè)中，系統(tǒng)是用過程和結(jié)果的革新來描述的，變得Customer-Driven，并且因此不得不改變系統(tǒng)性能以快速做出反應(yīng)。因此，一個大的挑戰(zhàn)是提供技術(shù)以限制自動控制系統(tǒng)對變化需要和新機會的反應(yīng)，所以，設(shè)計和操作知識可以實時的被再次利

35、用，在工業(yè)實踐中提供了一個重要的競爭面。</p><p>　　研究表明，在自動化系統(tǒng)中，程序?qū)崿F(xiàn)的方法已經(jīng)與計算機資源應(yīng)用的急速增長不能匹配。例如，可編程邏輯控制器（ＰＬＣ）程序仍然依靠一種方便的有邏輯梯形圖的程序?qū)崿F(xiàn)模式。結(jié)果，程序上的延遲和資源成了生產(chǎn)工業(yè)過程的主要絆腳石。在可編程邏輯控制器程序設(shè)計過程中，測試和調(diào)試可能會占用超過百分之五十的人力。在發(fā)展和傳播“ＳＴＡＴＥ－ＯＦ－ＴＨＥ－ＡＲＴ”已經(jīng)形成標(biāo)準(zhǔn)[

36、IEC 60848, 1999; IEC-61131-3, 1993; IEC 61499, 1998; ISO 15745-1, 1999]，但是，基本上這些標(biāo)準(zhǔn)都不能參與有效的程序和系統(tǒng)設(shè)計方面知識的革新。</p><p>　　系統(tǒng)的方法通過使用原有的軟件模塊，有助于增加設(shè)計自動化的水平，同時也將提供一種可管理的大規(guī)模系統(tǒng)設(shè)計的方法。同樣的，它也將改善軟件的質(zhì)量的可靠性，以及關(guān)系到系統(tǒng)的較高安全標(biāo)準(zhǔn)，尤其是這

37、些對環(huán)境有危害影響的，比如：機場控制、公共鐵路運輸。</p><p>　　軟件工業(yè)被認(rèn)為是系統(tǒng)性能的破壞者和系統(tǒng)復(fù)雜性的產(chǎn)生者。逐漸下降的硬件價格，破壞了對通過優(yōu)化程序獲得的軟件性能的需要。其結(jié)果是，一方面造成了大量而低效率的程序代碼，另一方面并沒有獲得高的硬件性能。其次，軟件變得難以掌握其程度的復(fù)雜；在現(xiàn)代自動化系統(tǒng)中，軟件設(shè)計和保持系統(tǒng)本質(zhì)幾乎變得不可能。尤其是，可編程邏輯控制器（ＰＬＣ）程序設(shè)計從二十五年前