資源目錄里展示的全都有預(yù)覽可以查看的噢，，下載就有,,請放心下載，原稿可自行編輯修改=【QQ：11970985 可咨詢交流】====================喜歡就充值下載吧。。。資源目錄里展示的全都有，，下載后全都有,,請放心下載，原稿可自行編輯修改=【QQ：197216396 可咨詢交流】==================== 畢業(yè)設(shè)計(jì)（論文）外文文獻(xiàn)翻譯 外文翻譯? PLC? 今天PLC?(programmable?logical?controller)，可編程序邏輯控制器)面臨著更為復(fù)雜的挑戰(zhàn)。當(dāng)初，它們悄悄地取代了繼電器、接觸器并時(shí)不時(shí)見諸于公司主框架的報(bào)告。而今，他們已經(jīng)組成了各種單元、被賦予新的任務(wù)、使用新的語言，并面臨著與各種新型控制產(chǎn)品競爭。作為每年一度PLC技術(shù)最新報(bào)道，我們請教了PLC市場銷售人員，制作了這個(gè)?？?。? 編程語言? 高級PLC編程語言已經(jīng)在有些方面很普及，但是最近高級編程語言已經(jīng)迅速發(fā)展。西門子的總經(jīng)理兼生產(chǎn)部長指出：“可編程控制在被廣泛的應(yīng)用與于精密操作，除了梯形圖邏輯以外的編程語言變得更加實(shí)用、有效和強(qiáng)大。例如，用梯形圖邏輯寫一個(gè)三角函數(shù)公式是非常困難的?！北唤邮盏恼Z言包括Boolean,控制系統(tǒng)流程圖編制，和如公式編制語言Graphtec和與它類似的語言，并且還有增加的重要語言如C語言和BASIC語言。? 過程控制中的PLC? PLC還沒有廣泛的應(yīng)用于過程控制中。是否會一直這樣下去呢？北美GE?Fanuc一系列和六系列的生產(chǎn)企劃經(jīng)理Ken?Jeannette說：“我覺得PLC將被用于過程控制但是對于過程控制又不是必須的。”? 一些廠家十分確定PLC不會廣泛用于過程控制。Rich?Ryan經(jīng)理提到PLC在食品、化學(xué)和石油等工業(yè)領(lǐng)域越來越多的應(yīng)用。他認(rèn)為PLC適合應(yīng)用于場合有兩種，他說：“第一，過程控制系統(tǒng)的型號不適合離散控制系統(tǒng)，剛開始這些產(chǎn)品的價(jià)格非常的高。而一個(gè)可編程控制器以它的體積小，價(jià)格低順理成章的被應(yīng)用。第二，你必須把電路和邏輯緊密的結(jié)合起來。例如，一組基本的控制器，連續(xù)的過程變量緊密的互相聯(lián)系在一起，以至于用可編程控制器來完成一系列的邏輯勝過沒有離散控制器的系統(tǒng)?！? Triconex?的總裁Bill?Barkovitz預(yù)測:“今后所有的控制器在過程控制系統(tǒng)的業(yè)務(wù)將引用更多的PLC技術(shù)，PLC功能比以往任何時(shí)候都要多?！? 通信和生產(chǎn)自動化協(xié)議（MAP）? 通信對于個(gè)人自動單元和自動化產(chǎn)業(yè)是很重要的。在過去的幾年里，我們聽到許多關(guān)于生產(chǎn)自動化協(xié)議的事情，并且許多公司已經(jīng)加入大有成功希望的事業(yè)。然而，當(dāng)一個(gè)完善的生產(chǎn)自動化協(xié)議說明書沒有及時(shí)出現(xiàn)時(shí)許多公司都很失望。Larry?Kotare說:”現(xiàn)在，生產(chǎn)自動化協(xié)議仍然是生產(chǎn)中一個(gè)發(fā)展的對象，一個(gè)說明書并不是最終的結(jié)果。例如，雖然當(dāng)新的生產(chǎn)自動化協(xié)議MAP3.0版本使用之時(shí)以MAP2.1版本為基礎(chǔ)的產(chǎn)品將會被汰，但是現(xiàn)在人們?nèi)匀粚a(chǎn)品用于MAP2.1版。 由于這些原因，許多PLC廠家緊盯著MAP的最新成果。如歐姆龍公司正在進(jìn)行一個(gè)有關(guān)MAP兼容性的項(xiàng)目。但是歐姆龍生產(chǎn)部門總經(jīng)理Frank?Newborn說由于缺少一個(gè)固定的標(biāo)準(zhǔn)，歐姆龍的產(chǎn)品并不涉及到MAP。? 由于個(gè)體PLC不可能無論何時(shí)廣泛的涉及到MAP，生產(chǎn)廠家正在考慮專用網(wǎng)絡(luò)。根據(jù)Sal?Probanzano的說法，用戶擔(dān)心如果他們廣泛的應(yīng)用生產(chǎn)廠家將會收回MAP，這樣將會留下一個(gè)不支持通信的交流框架。? 通用的?I/O? 然而關(guān)于?PLC?的兼容問題不同廠商的仍有顧慮，在另一端連接的?I/O?問題，更是支離破碎的。除了少數(shù)例外，I/O?仍然是專有技術(shù)。然而，還是有那些覺得?I/O?最終將更普及。GE?Fanuc?希望用它的智能?I/O?線這么做。各個(gè)獨(dú)立?I/O?制造商都在向同一方向進(jìn)發(fā)。? 許多人說，I/O?是這樣一個(gè)高價(jià)值項(xiàng)目，?PLC?制造商將永遠(yuǎn)希望保持它的專有性。就像Ken?Jannotta說的：?“?I/O?將在硬件銷售中不成比例。當(dāng)然每個(gè)?PLC?供應(yīng)商將試圖保護(hù)這一點(diǎn)?！?出于這個(gè)原因，他說，PLC?的制造商將不會開始銷售其他廠商的通用?I/O??！叭绻覀冮_始銷售那種產(chǎn)品，那我們還有什么可生產(chǎn)的？”?Jannotta?說道?。? 隨著更多智能?I/O?出現(xiàn)，Sal?Provanzano?認(rèn)為在不同的制造商中間這將導(dǎo)致更多的分化?！爱?dāng)?I/O?變得非常只能，并成為系統(tǒng)的一部分，到底哪個(gè)是I/O,哪個(gè)是CPU真的很難定義。如果你愿意，CPU?也同樣可以納入?I/O?的系統(tǒng)”?。? PLC的I/O和個(gè)人電腦的連接? 雖然不同的?PLC?廠商可能會繼續(xù)用專有的?I/O，但一些廠商使?I/O?連接到?IBM?PC?這樣的兼容設(shè)備成為可能。Alle?-?bradeley?和辛辛那提米拉克龍公司已經(jīng)擁有，并有傳言說，GE計(jì)劃將沿著同樣的思路。Bill?Ketelhut,?GE?Fanuc?北美的產(chǎn)品規(guī)劃經(jīng)理，認(rèn)為是?I/O?的普及“我覺得多個(gè)主機(jī)接口將代替?I/O??！彼f。朱迪格洛爾，Square?D?自動化產(chǎn)業(yè)市場經(jīng)理，將?PLC?看做是工業(yè)電腦。? PLC和個(gè)人電腦? 如果?IBM?7552，行動儀器?BC22，和其他計(jì)算機(jī)出現(xiàn)在工廠，這難道不意味著對?PLC?的新競爭。?“有一些對于更有利于電腦的控制功能?？删幊坛绦蚩刂破鞅黄冗m應(yīng)的這些要求?！?Rich?Ryan說。然而，在我們調(diào)查的廠商多數(shù)不認(rèn)為“個(gè)人電腦入侵”將對他們產(chǎn)生影響。大多數(shù)人說，PLC和PC除架構(gòu)之外，他們通常會做足夠的控制。他們認(rèn)為PC會做PLC的工作緊緊是因?yàn)楝F(xiàn)在PLC?I/O模塊能跟PC連接。他們相信這只是意味著，PLC?和個(gè)人電腦將能夠共享相同的數(shù)據(jù)。?? 富瑞恩說：“通用的計(jì)算機(jī)和可編程控制器內(nèi)在結(jié)構(gòu)不同，硬件結(jié)構(gòu)有內(nèi)置到幾乎每一個(gè)制造商的可編程控制器。如今定制的硬件來運(yùn)行梯形邏輯，解決機(jī)器代碼?！彼玫囊粋€(gè)根本的區(qū)別稱呼為“機(jī)器狀態(tài)”?富瑞安說：“當(dāng)你關(guān)閉機(jī)器，或中斷周期，或者跳轉(zhuǎn)到另一個(gè)周期，可編程控制器本身記得機(jī)器的狀態(tài)：定時(shí)器狀態(tài)是什么，計(jì)數(shù)器狀態(tài)是什么，鎖存的狀態(tài)是什么,但計(jì)算機(jī)本身不這樣做。 PLC PLCs (programmable logical controller) face ever more complex challengesthese?days?.?Where?once?they?quietly?replaced?relays?and?gave?an?occasional?report?to?a?corporate?mainframe,?they?are?now?grouped?into?cells,?given?new?job?and?new?languages,?and?are?forced?to?compete?against?a?growing?array?of?control?products.?For?this?year's?annual?PLC?technology?update?,we?queried?PLC?makers?on?these?topics?and?more?.? Programming?languages?? Higher?level?PLC?programming?languages?have?been?around?for?some?time?,but?lately?their?popularity?has?mushrooming.?"As?Raymond?Leveille,?vice?president?&?general?manager,?Siemens?Energy?&Automation?.inc;?Programmable?controls?are?being?used?for?more?and?more?sophisticated?operations,?languages?other?than?ladder?logic?become?more?practical,?efficient,?and?powerful.?For?example,?it's?very?difficult?to?write?a?trigonometric?function?using?ladder?logic?."Languages?gaining?acceptance?include?Boolean,?control?system?flowcharting,?and?such?function?chart?languages?as?Graphcet?and?its?variation?.And?there's?increasing?interest?in?languages?like?C?and?BASIC.? PLCs?in?process?control? Thus?far,?PLCs?have?not?been?used?extensively?for?continuous?process?control?.Will?this?continue??"The?feeling?that?I've?gotten,"?says?Ken?Jannotta,?manger,?product?planning,?series?One?and?Series?Six?product?,at?GE?Fanuc?North?America?,'is?that?PLCs?will?be?used?in?the?process?industry?but?not?necessarily?for?process?control."? Several?vendors?-obviously?betting?that?the?opposite?will?happen?-have?introduced?PLCs?optimized?for?process?application?.Rich?Ryan,?manger,?commercial?marketing,?Allen-bradley?Programmable?Controls?Div.,?cites?PLCs's?increasing?use?such?industries?as?food?,chemicals?,and?petroleum.?Ryan?feels?there?are?two?types?of?applications?in?which?they're?appropriate.?"one,"?he?says,"?is?where?the?size?of?the?process?control?system?that's?being?automated?doesn't?justify?DCS[distributed?control?system].With?the?starting?price?tags?of?chose?products?being?relatively?high,?a?programmable?controller?makes?sense?for?small,?low?loop?count?application?.The?second?is?where?you?have?to?integrate?the?loop?closely?with?the?sequential?logical?.Batch?controllers?are?prime?example?,where?the?sequence?and?maintaining?theprocess?variable?are?intertwined?so?closely?that?the?benefits?of?having?a?programmable?controller?to?do?the?sequential?logical?outweighs?some?of?the?disadvantages?of?not?having?a?distributed?control?system."? Bill?Barkovitz,?president?of?Triconex,?predicts?that?"all?future?controllers?that?come?out?in?the?process?control?system?business?will?embrace?a?lot?of?more?PLC?technology?and?a?lot?more?PLC?functionality?than?they?ever?did?before?."? Communications?and?MAP? Communications?are?vital?to?an?individual?automation?cell?and?to?be?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?bandwagon.Many,??however,?were?disappointed?when?a?fully-defined?and?completed?MAP?specification?didn't?appear?immediately?.Says?Larry?Komarek:?"Right?now,?MAP?is?still?a?moving?target?for?the?manufacturers,?a?specification?that?is?not?final?.Presently,?for?example.?people?are?introducing?products?to?meet?the?MAP2.1standard?.Yet2.1-based?products?will?be?obsolete?when?the?new?standard?for?MAP3.0?is?introduced."? Because?of?this,?many?PLC?vendors?are?holding?off?on?full?MAP?implementations.?Omron,?for?example,?has?an?ongoing?MAP-compatibility?program;but?Frank?Newburn,?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.? Since?it's?unlikely?that?an?individual?PLC?would?talk?to?broad?MAP?anyway,?makers?are?concentrating?on?proprietary?networks.?According?to?Sal?Provanzano,?users?fear?that?if?they?do?get?on?board?and?vendors?withdraw?from?MAP,?they'll?be?the?ones?left?holding?a?communications?structure?that's?not?supported.? Universal?I/O? While?there?are?concerns?about?the?lack?of?compatible?communications?between?PLCs?from?different?vendors,?the?connection?at?the?other?end-the?I/O-is?even?more?fragmented?.With?rare?exceptions,?I/O?is?still?proprietary?.Yet?there?are?those?who?feel?that?I/O?will?eventually?become?more?universal?.GE?Fanuc?is?hoping?to?do?that?with?its?Genius?smart?I/O?line.?The?independent?I/O?makers?are?pulling?in?the?same?direction.?? Many?say?that?I/O?is?such?a?high-value?item?that?PLC?makers?will?always?want?to keep?it?proprietary?.As?Ken?Jannotta,?says:?"The?I/O?is?going?to?be?a?disproportionate?amount?of?the?hardware?sale.?Certainly?each?PLC?vendor?is?going?to?try?to?protect?that.?"For?that?reason,?he?says,?PLC?makers?won't?begin?selling?universal?I/O?system?from?other?vendor.?"if?we?start?selling?that?kind?of?product,?"says?jannotta,?"what?do?we?manufacture?"? With?more?intelligent?I/O?appearing,?Sal?Provanzano?feels?this?will?lead?to?more?differentiation?among?I/O?from?different?makers.?"Where?the?I/O?becomes?extremely?intelligent?and?becomes?part?of?the?system,?"he?says,?"it?really?is?hard?to?define?which?is?the?I/O?and?which?is?CPU.?It?really?CPU,?if?you?will,?is?equally?integrated?into?the?system?as?the?I/O."? Connecting?PLC?I/O?to?PCs? While?different?PLCs?probably?will?continue?to?use?proprietary?I/O,?several?vendors?make?it?possible?to?connect5?their?I/O?to?IBM?PC-compatible???equipment.?Alle-bradeley,?Could,?and?Cincinnati?Milacron?already?have,?and?rumor?has?it?that?GE?is?planning?something?along?these?same?lines?.Bill?Ketelhut,?manage?of?product?planning?at?GE?Fanuc?North?America?,sees?this?sort?of?thing?as?alternative?to?universal?I/O."I?think?the?trend?,instead?of?toward?universal?I/O,?will?be?multiple?host?interface?,"?he?says?.Jodie?Glore?,director?of?marking,?Square?D?Automation?Products,?Views?it?as?another?indication?that?PLCs?are,?and?have?been?for?some?time,?industrial?computers.? PLCs?and?PCs? If?the?IBM?7552,?the?Action?Instruments?BC22,and?other?computers?are?appearing?on?the?factory?floor,?won't?this?mean?new?competition?for?PLCs??Rich?Ryan:?"There?are?some?control?functions?that?are?better?jobs?for?computers.?Programmable?controllers?have?been?forced?to?fit?into?those?applications.?"Yet,?the?majority?of?vendors?we?surveyed?don't?like?the?"PC?invasion"?will?pose?a?problem?for?them?.Most?said?that?PLCs?and?PCs?are?enough?apart?in?architecture?that?they?will?usually?do?the?control.?They?don't?feel?that?PCs?will?take?jobs?from?PLCs?just?because?PLC?I/O?modules?can?now?be?connected?to?PCs;?they?believe?this?simply?means?that?PLCs?and?PCs?will?be?able?to?share?the?same?data.? "There?are?inherent?architectural?differences?between?a?general?purpose?computer,"?says?Rich?Ryan,?"and?a?programmable?controller?.There?are?hardware?constructs?built?into?almost?every?manufacture's?programmable?controller?today?that?customize?the?hardware?to?run?ladder?logic?and?to?solve?machine?code.?"One?fundamental?difference?he?cites?is?called?state?of?the?machine?.Ryan:?"When?you?shut?the?machine?off,?or?interrupt?the?cycle,?or?you?jump?to?another?spot?in?the?cycle,?programmable?controllers?inherently?remember?the?state?of?the?machine:?what?the?timers?were,?what?the?counters?were?,what?the?states?of?all?the?latches?were?.Computers?don't?inherently?do?that."? 7