PLC中英文翻譯.doc

PLC今天的PLC（可編程邏輯控制器）將面對日益復(fù)雜的挑戰(zhàn)。一旦他們悄悄地取代繼電器，偶爾向主機(jī)報告，如果他們將他們比作細(xì)胞，賦予新的工作和新的語言，將被迫和大量的控制產(chǎn)品競爭。對于今年的年度PLC技術(shù)的更新，我們對PLC的制造商會就這些主題提出更多問題。編程語言更高水平的PLC編程語言已經(jīng)推行有一段時間了，但最近的流行，如雨后春筍般。正如雷蒙德萊韋耶，副總裁兼總經(jīng)理，西門子能源和自動化公司，可編程控制正在為更復(fù)雜的操作使用，梯形邏輯比語言變得更加實際，有效和強(qiáng)大的。舉例來說，很難寫三角函數(shù)使用梯形邏輯。“語言為人們所接受，包括布爾，控制系統(tǒng)流程圖，這種功能圖及其變化圖表語言。而且有越來越多像C和BASIC語言的興趣。”在過程的PLC控制到目前為止，PLC的沒有大量用于連續(xù)過程控制，會繼續(xù)嗎？“我感覺到了，PLC將用于過程工業(yè)，但不一定過程控制?！?Jannotta說。 幾個供應(yīng)商，顯然是把賭注押在相反會發(fā)生，已經(jīng)實行了PLC的應(yīng)用優(yōu)化的過程。富瑞安的經(jīng)理認(rèn)為PLC將越來越多地使用食品等行業(yè)，化工，石化.Ryan認(rèn)為有兩種類型的應(yīng)用程序中，他們是合適的?！爸?，”他說，“是其中的過程控制系統(tǒng)，目前已被沒有理由自動化DCS的大小分布式控制系統(tǒng)隨著價格標(biāo)簽開始。產(chǎn)品的選擇是比較高，可編程控制器為小，低環(huán)數(shù)的應(yīng)用意義。第二種是你必須融入順序邏輯。批次控制循環(huán)密切合作是最好的例子，那里的順序和維持過程變量是交織在一起的密切合作，使擁有一個可編程控制器的邏輯順序做的好處遠(yuǎn)遠(yuǎn)超過了不具有分布式控制系統(tǒng)的一些缺點。”Bill Barkovitz， Triconex的總統(tǒng)，預(yù)言：“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功能比以往任何時候都要多?！蓖ㄐ藕鸵?guī)范在整體上通信是至關(guān)重要的個人自動化單元對自動化工廠來說。我們聽說了很多規(guī)范在過去數(shù)年，許多公司都紛紛跟進(jìn)。但是，不少人失望的發(fā)現(xiàn)完成地圖規(guī)范并沒有立即出現(xiàn)。拉里科馬雷克說：“現(xiàn)在，規(guī)范仍然是一個移動目標(biāo)，規(guī)范沒有最終決定，對于制造商。目前，正在推出的產(chǎn)品樣本.人們使其產(chǎn)品滿足MAP2.1標(biāo)準(zhǔn)。然而，新標(biāo)準(zhǔn)MAP3.0被引進(jìn)時，MAP2.1為基礎(chǔ)的產(chǎn)品將被淘汰時?！闭驗槿绱耍S多PLC廠商正在制定完整的規(guī)范. 例如Omron，擁有一個完整的兼容程序，但弗蘭克紐伯恩，副歐姆龍工業(yè)部總裁，報告說，由于缺乏公司的定義，歐姆龍的PLC還談不上規(guī)范。 由于不太可能將個人的PLC廣泛的交談，制造商更專注于專有的網(wǎng)絡(luò).按照薩爾Provanzano說法，用戶擔(dān)心，如果他們不從規(guī)則上和供應(yīng)商妥協(xié)，他們將要加大對通信結(jié)構(gòu)的不支持。通用的I/O然而大多數(shù)PLC的兼容問題不同廠商的溝通不夠，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是仍然專有技術(shù)。然而，誰是那些感覺的I/O最終將成為更具有普遍性。GE Fanuc的希望這樣做與天才智能I/O線.各個獨立I/O制造商都在同一方向進(jìn)發(fā)。許多人說，I/O是這樣一個高價值項目， PLC制造商將永遠(yuǎn)希望保持它的專有性。由于肯Jannotta。說：“ I/O將在硬件銷售中不成比例。當(dāng)然每個PLC供應(yīng)商將試圖保護(hù)這一點?！背鲇谶@個原因，他說，PLC的制造商將不會開始銷售通用I/O和其他廠商的系統(tǒng)?！叭绻覀冮_始銷售該產(chǎn)品的實物，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)，薩爾Provanzano認(rèn)為在不同的制造商中間這將導(dǎo)致更多的分化?！澳睦锏腎/O變得非常聰明，并成為系統(tǒng)的一部分真的很難定義，哪些是I/O，哪些是CPU.隨著分布式的發(fā)展，如果你愿意，CPU也同樣可以納入作為I/O的系統(tǒng)”PLC的 I/O和個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，通用的電氣計劃將沿著同樣的思路?？颂貭柡?， GE Fanuc北美的產(chǎn)品規(guī)劃經(jīng)理，認(rèn)為是I/O的普及“我想多個主機(jī)接口將代替I/O的趨勢，”他說。朱迪格洛爾，市場經(jīng)理，Square D Automation Products，將PLC看做是工業(yè)電腦。PLC和電腦如果IBM 7552，行動儀器BC22，和其他計算機(jī)出現(xiàn)在工廠，這意味著不會對PLC的新的競爭？富瑞安：“有一些控制功能，可用于電腦.可編程程序控制器更好的工作已被迫適應(yīng)這些應(yīng)用?！叭欢谖覀冋{(diào)查的廠商多數(shù)不認(rèn)為“個人電腦入侵”將對他們產(chǎn)生問題。大多表示PLC和PC結(jié)構(gòu)上的差別決定他們不同的作用，PC將主管通訊和管理，PLC則進(jìn)行控制，他們相信這只是意味著，PLC和個人電腦將能夠共享相同的數(shù)據(jù)。富瑞恩說：“通用的計算機(jī)內(nèi)在結(jié)構(gòu)不同，可編程控制器硬件結(jié)構(gòu)有內(nèi)置到幾乎每一個制造商的可編程控制器。今天定制的硬件來運行梯形邏輯，解決機(jī)器代碼?！痹诟镜膮^(qū)別上，他引用了一個稱呼“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)到另一個周期，現(xiàn)場可編程控制器本身記得機(jī)器的狀態(tài)：定時器狀態(tài)是什么，計數(shù)器狀態(tài)是什么，鎖存的狀態(tài)是什么,但計算機(jī)本身不這樣做?！盤LCPLCs (programmable logical controller) face ever more complex challenges these 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 years 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, its 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 theres increasing interest in languages like C and BASIC.PLCs in process controlThus far, PLCs have not been used extensively for continuous process control .Will this continue? The feeling that Ive 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 PLCss increasing use such industries as food ,chemicals ,and petroleum. Ryan feels there are two types of applications in which theyre appropriate. one, he says, is where the size of the process control system thats being automated doesnt justify DCSdistributed 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 the process 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 MAPCommunications are vital to an individual automation cell and to be automated factory as a whole. Weve 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 didnt 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 Omrons Industrial Division ,reports that because of the lack of a firm definition ,Omrons PLCs dont yet talk to MAP.Since its 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, theyll be the ones left holding a communications structure thats not supported.Universal I/OWhile 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 wont 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 PCsWhile 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 PCsIf the IBM 7552, the Action Instruments BC22,and other computers are appearing on the factory floor, wont 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 dont like the PC invasion will pose a problem for them .Most said that PLCs and P