外文翻譯--pac新一代工業(yè)控制系統(tǒng)可編程自動化控制發(fā)展的未來

1、<p><b>　　中文5720字</b></p><p>　　PAC——新一代工業(yè)控制系統(tǒng), 可編程自動化控制發(fā)展的未來</p><p>　　隨著許多廠商已生產出能結合PC功能和PLC可靠性的可編程自動化控制器（PAC），目前控制系統(tǒng)已逐漸開始采用PAC。本白皮書介紹PAC的起源以及它與PLC和PC的區(qū)別，并指出了使用PAC的工業(yè)控制未來發(fā)展方向。<

2、/p><p><b>　　目錄 </b></p><p>　　PAC將成為未來的工業(yè)控制方式 </p><p>　　“80-20” 法則 </p><p><b>　　構建更好的控制器 </b></p><p>　　兩種不同的軟件解決方案 </p><p>

3、;　　PAC的視覺和測量應用 </p><p>　　PAC免除了對專門硬件的需要 </p><p>　　LabVIEW用于自動化控制 </p><p><b>　　NI PAC系統(tǒng)</b></p><p>　　PAC將成為未來的工業(yè)控制方式和基于PC控制系統(tǒng)相比，有關PLC（可編程邏輯控制器）優(yōu)勢和劣勢的激烈爭論已經持續(xù)

4、了十年。由于PC和PLC在技術上的差別越來越小，并且隨著PLC采用了商業(yè)化（COTS）硬件以及PC能采用實時操作系統(tǒng)，從而出現(xiàn)了一種新類型的控制器——PAC。PAC的概念是由自動化研究機構 (ARC) 提出的，它表示可編程自動化控制器，用于描述結合了PLC和PC功能的新一代工業(yè)控制器。傳統(tǒng)的PLC廠商使用PAC的概念來描述他們的高端系統(tǒng)，而PC控制廠商則用來描述他們的工業(yè)化控制平臺。</p><p>　　“80-

5、20” 法則 </p><p>　　在PLC被開發(fā)出來的三十年里，它經過不斷地發(fā)展，已經能結合模擬I/O，網絡通信以及采用新的編程標準如IEC 61131-3。然而，工程師們只需利用數(shù)字I/O和少量的模擬I/O數(shù)以及簡單的編程技巧就可開發(fā)出80%的工業(yè)應用 。來自ARC、聯(lián)合開發(fā)公司（VDC）以及網上PLC培訓資源PLC.net的專家估計： </p><p>　　77%的PLC被用于小型應

6、用（低于128 I/O） </p><p>　　72%的PLC I/O是數(shù)字的 </p><p>　　80%的PLC應用可利用20條的梯形邏輯指令集來解決</p><p>　　由于采用傳統(tǒng)的工具可以解決80%的工業(yè)應用，這樣就強烈地需要有低成本簡單的PLC；從而促進了低成本微型PLC的增長，它帶有用梯形邏輯編程的數(shù)字I/O。然而，這也在控制技術上造成了不連續(xù)性，一方

7、面80%的應用需要使用簡單的低成本控制器，而另一方面其它的20%應用則超出了傳統(tǒng)控制系統(tǒng)所能提供的功能。工程師在開發(fā)這些20%的應用需要有更高的循環(huán)速率，高級控制算法，更多模擬功能以及能更好地和企業(yè)網絡集成。</p><p>　　在八十和九十年代，那些要開發(fā)“20%應用”的工程師們已考慮在工業(yè)控制中使用PC。PC所提供的軟件功能可以執(zhí)行高級任務，提供豐富的圖形化編程和用戶環(huán)境，并且PC的COTS部件使控制工程師能

8、把不斷發(fā)展的技術用于其它應用。這些技術包括浮點處理器；高速I/O總線，如PCI和以太網；固定數(shù)據存儲器；圖形化軟件開發(fā)工具。而且PC還能提供無比的靈活性，高效的軟件以及高級的低成本硬件。</p><p>　　然而，PC還不是非常適合用于控制應用。盡管許多工程師在集成高級功能時使用PC，這些功能包括模擬控制和仿真、連接數(shù)據庫、網絡功能以及和第三方設備通信，但是PLC仍然在控制領域中處于統(tǒng)治地位。基于PC控制的主要問

9、題是標準PC并不是為嚴格的工業(yè)環(huán)境而設計的。</p><p>　　PC主要面臨三大問題： </p><p>　　穩(wěn)定性：通常PC的通用操作系統(tǒng)不能提供用于控制足夠的穩(wěn)定性。安裝基于PC控制的設備會迫使處理系統(tǒng)崩潰和未預料到的重啟。 </p><p>　　可靠性：由于PC帶有旋轉的磁性硬盤和非工業(yè)性牢固的部件，如電源，這使得它更容易出現(xiàn)故障。 </p>

10、<p>　　不熟悉的編程環(huán)境：工廠操作人員需要具備在維護和排除故障時恢復系統(tǒng)的能力。使用梯形邏輯，他們可以手動迫使線圈恢復到理想狀態(tài)，并能快速修補受影響的代碼以快速恢復系統(tǒng)。然而，PC系統(tǒng)需要操作人員學習新的更高級的工具。</p><p>　　盡管某些工程師采用具有堅固硬件和專門操作系統(tǒng)的專用工業(yè)計算機，但是由于PC可靠性方面的問題絕大多數(shù)工程師還是避免在控制中使用PC。此外，在PC中的用于各種自動化任

11、務的設備，如I/O、通信、或運動可能需要不同的開發(fā)環(huán)境。</p><p>　　因此那些要開發(fā)“20%應用”的工程師們要么使用一個PLC無法輕松實現(xiàn)系統(tǒng)所需的功能，要么采用既包含PLC又包含PC的混合系統(tǒng)，他們利用PLC來執(zhí)行代碼的控制部分，用PC來實現(xiàn)更高級的功能。因而現(xiàn)在許多工廠車間使用PLC和PC相結合的系統(tǒng)，利用系統(tǒng)中的PC進行數(shù)據記錄，連接條碼掃描儀，在數(shù)據庫中插入信息以及把數(shù)據發(fā)布到網上。采用這種方式建

12、立系統(tǒng)的主要問題是該系統(tǒng)常常難以構建，排除故障和維護。系統(tǒng)工程師常常被要結合來自多個廠商軟硬件的工作所困擾，這是因為這些設備并不是為了能協(xié)同工作而設計的。</p><p><b>　　構建更好的控制器 </b></p><p>　　由于沒有適合的PC或PLC解決方案，那些需要開發(fā)復雜應用的工程師就和控制廠商密切合作開發(fā)新的產品。他們需要新產品能結合PC的高級軟件功能和

13、PLC的可靠性。這些重要用戶為PLC和基于PC控制的公司提供了產品開發(fā)指導。</p><p>　　實現(xiàn)軟件的功能不僅需要有高級的軟件，而且控制器的硬件功能也需要有所提高。由于世界范圍內對PC部件的需求在下降，所以許多半導體廠商開始為工業(yè)應用重新設計他們的產品。目前控制領域的廠商已開始在工業(yè)控制產品中使用工業(yè)化浮點處理器、DRAM、固態(tài)存儲器如CompactFlash以及快速Ethernet芯片。這使得廠商能利用基

14、于PC控制系統(tǒng)的靈活性和可用性來開發(fā)更為強大的軟件，而且該PC控制系統(tǒng)還可運行實時操作系統(tǒng)以保證可靠性。</p><p>　　這種新的控制器是為解決“20%”的應用問題而設計的，它結合了PLC和PC兩者的優(yōu)點。ARC的工業(yè)分析家把這種設備稱為可編程自動化控制器，即PAC。在ARC的“可編程邏輯控制器世界概覽”研究中，他們給出了PAC的五個主要特性。這些控制器特性是通過定義軟件的能力來實現(xiàn)其功能的。 </p&

15、gt;<p>　　“多功能性，在一個平臺上有邏輯、運動、PID控制、驅動和處理中的至少兩種以上功能?！背藶榱藢崿F(xiàn)特殊的協(xié)議如SERCOS要對I/O做一些改進；而且軟件還能提供邏輯、運動、處理和PID的功能。例如，運動控制作為軟件控制循環(huán)，它能從正交編碼器上讀取數(shù)字輸入，執(zhí)行模擬控制循環(huán)并輸出控制設備的模擬信號。 </p><p>　　“單一的多規(guī)程開發(fā)平臺使用通用標簽和單一的數(shù)據庫來訪問所有的參數(shù)

16、和功能?！庇捎赑AC是為更為高級的應用如多功能而設計的，他們需要更為高級的軟件。為了能高效地設計系統(tǒng)，軟件必須是單一的集成化軟件包，而不是多種分離的軟件工具，這些軟件工具在工程上不能無縫地協(xié)同工作。 </p><p>　　“通過結合IEC61131-3，用戶向導和數(shù)據管理，軟件工具能設計出在跨越多個機器和處理單元的處理流程?！焙喕到y(tǒng)設計的另一方面是具有高級的圖形化開發(fā)工具，利用該工具可以使工程師很輕松地把處理的

17、概念轉變?yōu)槟軐嶋H控制機器的代碼。 </p><p>　　“開放的模塊化構架能解決的工業(yè)應用可從控制分布于工廠機器到加工車間的操作單元?！庇捎谒械墓I(yè)應用都需要有高度的定制特性，所以硬件必須是模塊化的以便工程師們可以選擇合適的部件。而且，軟件也必須能讓工程師增加和拆除模塊以設計出所需的系統(tǒng)。 </p><p>　　“采用已有的網絡接口標準，語言等，如TCPIP，OPC&XML和SQ

18、L查詢語言?！蹦芎推髽I(yè)的網絡通信對于現(xiàn)代化控制系統(tǒng)是非常關鍵的。盡管PAC包含有以太網接口，但是為了要把設備和工廠其它系統(tǒng)無問題地集成在一起，通信軟件是至關重要的。</p><p>　　兩種不同的軟件解決方案一方面軟件是PAC和PLC主要的區(qū)別，而另一方面廠商在提供高級軟件的方式上也有所不同。通常他們以目前已有的控制軟件作為起點，不斷增加PAC編程所需的功能、可靠性和易用性。一般說來，有兩種提供PAC軟件的方式

19、：基于PLC控制的軟件和基于PC控制的軟件</p><p>　　基于PLC概念的軟件方案</p><p>　　傳統(tǒng)的PLC軟件廠商以可靠且易用的掃描式架構軟件為起點，并逐漸增加新的功能。PLC軟件根據通用模型而建立：輸入掃描，控制代碼運行，輸入更新，以及常規(guī)功能執(zhí)行。由于輸入循環(huán)，輸出循環(huán)和常規(guī)循環(huán)都是隱藏的，所以控制工程師只需關注控制代碼的設計。由于廠商已完成了大部分工作，這種嚴格的控制

20、架構使得建立控制系統(tǒng)更為容易和快速。這些系統(tǒng)的嚴格性也能讓控制工程師在開發(fā)可靠的程序時無需深入了解PLC的底層操作。然而，作為PLC主要優(yōu)勢的這種嚴格的掃描式構架也導致其靈活性的欠缺。絕大多數(shù)PLC廠商通過在已有的掃描式架構中增加新的功能來建立PAC軟件，這些新功能包括以太網通信，運動控制和高級算法。然而，通常他們會保留PLC熟悉的編程方式以及其在邏輯和控制方面固有的特點。因此這種PAC軟件通常是為了適合特殊類型應用而設計的，如邏輯，運

21、動和PID，但是對于定制的應用則缺乏靈活性，如通信、數(shù)據記錄或定制的控制算法。</p><p>　　基于PC概念的軟件方案</p><p>　　傳統(tǒng)PC軟件廠商以非常靈活的通用編程語言為起點，能提供對硬件的深層次訪問。該種軟件也具有可靠性、確定性以及預設的控制架構。盡管工程師能為PLC編程人員建立起掃描式構架，但是它并不是基于PC的軟件所固有的。這些使得PC軟件極為靈活，非常適合那些需要高

22、級的架構、編程技巧或者系統(tǒng)級控制的復雜應用，但卻使本應簡單的應用復雜化。</p><p>　　這些廠商首先要能提供通用操作系統(tǒng)如Windows所不具備的可靠性和確定性。它們可以通過采用實時操作系統(tǒng)（RTOS）如來自Ardence的Phar Lap或Wind River的VxWorks來實現(xiàn)。這些RTOS能控制系統(tǒng)的各個層面，從I/O讀寫速率到控制器上各個線程的優(yōu)先級。然后為了使工程師能更為容易地開發(fā)出可靠的控制程

23、序，廠商增加了抽象層和I/O讀寫架構。因而這種靈活軟件非常適合于定制控制，數(shù)據記錄和通信，但舍棄PLC編程架構的代價是使程序的開發(fā)難度增加。</p><p>　　NI已開發(fā)出能運行LabVIEW程序的一系列PAC運載平臺。LabVIEW已成為測試和測量軟件的事實標準。它具有直觀的類似于流程圖的圖形化編程方式，并通過易用的界面來提供高級編程語言所具備的所有功能。利用LabVIEW RT和LabVIEW FPGA，我

24、們能結合LabVIEW和實時操作系統(tǒng)并直接下載到FPGA（現(xiàn)場可編程門陣列）平臺來提供可靠性和確定性。</p><p>　　基于PAC的視覺和測量應用</p><p>　　NI具有測量的行業(yè)背景，它通過引入高速測量和機器視覺使PAC超越了簡單的I/O。在許多工業(yè)應用中需要高速采集測量結果以用于振動或功率品質分析。采集到的數(shù)據用來監(jiān)測旋轉機械的狀態(tài)，確定維護時間表，識別電機的磨損程度以及調整

25、控制算法。工程師們通常使用專門的數(shù)據采集系統(tǒng)或獨立儀器來采集這些數(shù)據并利用通信總線把數(shù)據輸入到控制系統(tǒng)。而NI的PAC正可以以每秒百萬個采樣點的速率直接進行高精度的測量，并把數(shù)據直接傳送到控制系統(tǒng)來立即處理。</p><p>　　工程師們也可以在他們的控制系統(tǒng)中使用視覺功能。過去十年中視覺在自動化領域已得到了迅猛地發(fā)展。在生產環(huán)境中，有許多產品缺陷或錯誤使用傳統(tǒng)的測量方法是很難識別出來的，而通過視覺方式則能檢測。

26、常見的應用包括用于生產或裝配檢驗的零件檢測，如檢查電路板上器件的位置是否正確，識別光學字符（OCR）來檢查日期條碼或對產品進行分類，以及進行光學測量來找出產品的瑕疵或對產品按質量等級進行分類。目前許多工廠采用獨立的智能攝像頭，它要和生產處理控制器進行通信。NI的PAC引入帶有邏輯和運動控制的視覺或是高速測量功能，從而使得工程師們無需集成其他的硬件和軟件平臺。</p><p>　　PAC免除了對于專門硬件的需要&l

27、t;/p><p>　　PAC代表著可編程控制器的最新技術，它未來發(fā)展的關鍵取決于嵌入式技術的引入。比如要能通過軟件來定義硬件。電子廠商常使用現(xiàn)場可編程門陣列（FPGA）這樣的電子器件來開發(fā)定制的芯片，它可以讓新設備智能化。這些設備包含有能執(zhí)行多種功能的可配置邏輯塊，連接這些功能塊的可編程交聯(lián)點以及為芯片輸入輸出數(shù)據的I/O塊。通過定義這些可配置邏輯塊的功能，其彼此連接以及相應的I/O，電子設計人員即可以開發(fā)出定制的芯

28、片，而不需要花錢來生產專門的ASIC。FPGA如同有一個計算機，其內部電路能被重新連接來運行特定的應用程序。</p><p>　　以前只有那些熟悉底層編程語言如VHDL的硬件設計人員才能利用FPGA技術。然而，現(xiàn)在工程師們已可以用LabVIEW FPGA來開發(fā)出定制的控制算法并把它下載到FPGA芯片上。通過該特性工程師們可以使硬件具備實時的功能，如限度和接近傳感器檢測和傳感器狀態(tài)監(jiān)控。由于控制代碼直接在芯片上運行

29、，所以工程師們能快速開發(fā)采用定制的通信協(xié)議或高速循環(huán)的程序：數(shù)字控制循環(huán)速度可高達1 MHz，模擬控制循環(huán)的速度可為200kHz。</p><p>　　LabVIEW用于自動化控制 由于LabVIEW (ni.com/china/labview)具有強大的功能和圖形化編程的易用性，基于LabVIEW的PAC 非常適合有如下要求的應用： </p><p>　　圖形化 由于LabVIEW 編

30、程天生引入圖形用戶界面，您可以為控制系統(tǒng)提供圖形化人機界面。 </p><p>　　測量（高速數(shù)據采集，視覺和運動）。NI在包括視覺采集的高速I/O方面有著長期經驗，因此您可以在您的標準控制系統(tǒng)中使用振動或機器視覺等功能。 </p><p>　　處理能力： 在某些應用中，您需要有專門的控制算法、高級的信號處理或數(shù)據記錄。使用LabVIEW，您可以用NI或第三方的工具來建立定制的控制代碼，實

31、現(xiàn)如JTFA的信號處理，或本地及遠程記錄數(shù)據。 </p><p>　　平臺： 利用 LabVIEW，您能開發(fā)出用于各種平臺的代碼，這些平臺包括PC，嵌入式控制器，F(xiàn)PGA芯片或手持式PDA。 </p><p>　　通信 ：利用LabVIEW的數(shù)據庫連接，OPC和基于網絡瀏覽器的操作界面，您能很容易地把數(shù)據傳送到企業(yè)數(shù)據庫中。</p><p><b>　　N

32、I PAC系統(tǒng)</b></p><p>　　NI提供五種基于LabVIEW的PAC平臺。</p><p>　　PXI是由多個廠商制定的基于CompactPCI架構的工業(yè)標準化PAC硬件平臺，它能提供模塊化、緊湊而堅固的工業(yè)化系統(tǒng)。PXI系統(tǒng)的嵌入式控制器內置上GHz的高性能處理器。您可以選用來自NI或第三方廠商的PXI和CompactPCI模塊。PXI能提供最為廣泛的I/O，包

33、括有1000 V的隔離式模擬輸入，高容量數(shù)字I/O，用于機器視覺的模擬/數(shù)字幀抓取器，聯(lián)合多軸運動模塊。PXI模塊的前端都配置有方便電纜連接的接口。PXI平臺提供全面的測量模塊，以及包括CAN，DeviceNET，RS-232，RS-485，Modbus和Foundation Fieldbus的廣泛連接性。</p><p>　　Compact FieldPoint產品系列包括有可熱抽換的模擬和數(shù)字I/O模塊和控制

34、器，并帶有以太網和串行總線接口。其中I/O模塊能直接連接熱電偶、RTD、應力計、4-20 mA傳感器、5-30 V的直流信號以及0-250 V的交流信號。Compact FieldPoint網絡通信接口能自動通過以太網絡傳送數(shù)據。您也可以以讀寫本地I/O的方式來讀寫經由網絡傳輸?shù)膸子⒗镏獾腎/O。由于軟件的接口非常簡單，您可以快速地建立和編寫Compact FieldPoint應用程序，但又不失復雜控制，數(shù)據記錄和通信的強大功能。&l

35、t;/p><p>　　Compact Vision System整合了高性能Intel處理器、FPGA，數(shù)字I/O和三個1394端口。這種PAC天生就可以通過FireWire（IEEE1394）技術在控制應用中使用視覺功能，并兼容80多種工業(yè)攝像頭。利用CVS上的可重復配置FPGA和數(shù)字I/O通路，您也可以進行低通道數(shù)的數(shù)字和步進電機控制。當使用LabVIEW編程時，您還能配置該系統(tǒng)以得到高性能的視覺以及高速的數(shù)字控

36、制和步進電機控制。</p><p>　　CompactRIO是基于FPGA的可重復配置控制和采集系統(tǒng)，它是為需要高度定制和高速控制的應用而設計的。該架構采用實時嵌入式處理器，并結合可重復配置I/O（RIO）的FPGA內核來實現(xiàn)復雜的算法和定制的計算。CompactRIO平臺可使用多達八個模擬或數(shù)字I/O模塊。這些模塊可由NI或其它廠商提供。CompactRIO平臺非常適合如機器控制這樣的復雜和高速應用，并且，對于

37、那些通常需要開發(fā)專門的硬件的應用，結合了FPGA的這種系統(tǒng)也是非常好的選擇。</p><p>　　標準的工業(yè)計算機也可以使用NI所提供的廣泛的PCI模塊。這些插入式板卡包含有為模擬和數(shù)字I/O，運動控制和機器視覺而設計的硬件。要得到確定性、實時的性能，可結合PCI硬件和運行于基于PC的實時操作系統(tǒng)上的LabVIEW來實現(xiàn)。LabVIEW RT可被加載到絕大多數(shù)標準的工業(yè)PC上，從而能提供用于工業(yè)測量和控制的低成本

38、平臺。</p><p>　　Downloading more PAC technical paper and</p><p>　　video frequency course</p><p>　　Has produced along with many merchants can unify the PC function and the PLC reliable

39、programmable automation controller (PAC), at present the control system gradually started to use PAC. This white paper introduced PAC the origin as well as it with PLC and the PC difference, and had pointed out will use

40、PAC the industry to control the future development direction.</p><p>　　Table of contents </p><p>　　PAC will become the future the industry control mode </p><p>　　"80-20" p

41、rinciple </p><p>　　Constructs a better controller </p><p>　　Two kind of different softwares solution </p><p>　　PAC vision and survey application </p><p>　　PAC has avoid

42、ed to the special hardware need </p><p>　　LabVIEW uses in the automated control</p><p>　　NI PAC system</p><p>　　PAC will become the future the industry control mode with compares ba

43、sed on the PC control system, related PLC (programmable logical controller) the superiority and the inferiority intense argument has already continued for ten years. Because PC and PLC are more and more small in the tech

44、nical difference, and has used the commercialization along with PLC (COTS) the hardware as well as PC can use the real-time operating system, thus appeared one kind of new form controller - PAC. The PAC concept </p>

45、;<p>　　"80-20" principle </p><p>　　In PLC in 30 years which developed, it passes through develops unceasingly, already could unify simulates I/O, the network corresponds as well as uses new

46、programming standard like IEC 61131-3. However, engineers only must use digital I/O and few simulations I/O number as well as simple programming skill on potential 80% industrial application. Comes from ARC, the unit exp

47、loitation company (VDC) as well as on the net PLC training resources PLC. The net expert estimated that, </p><p>　　77% PLC uses in the small application (being lower than 128 I/O) </p><p>　　72%

48、PLC I/O is a numeral </p><p>　　80% PLC application may use 20 trapezoidal logical sets of instructions to solve</p><p>　　Because uses traditional the tool to be possible to solve 80% industrial

49、application, like this intensely needs to have low cost simple PLC; Thus promoted the low cost miniature PLC growth, it has the useful trapezoidal logical programming digital I/O. However, this has also created the disco

50、ntinuity in the control technology, on the one hand 80% application need to use the simple low cost controller, but on the other hand other 20% application then have surpassed the function which the traditio</p>&

51、lt;p>　　In 80 and the 90's, these must develop "20% application" engineers had considered uses PC in the industry control. PC provides the software function may carry out the senior task, provides the ric

52、h programming and the user environment, and the PC COTS part enables control engineer the technology which develops unceasingly to use in other applications. These technologies including floating point processor; High sp

53、eed I/O main line, like PCI and ethernet; Fixed data memory; software development ki</p><p>　　However, PC is not extremely suitablly uses in controlling the application. Although many engineers in integrated

54、 senior function time uses PC, these functions including simulation control and simulation, connection database, network function nf as well as with third party equipment correspondence, but PLC still was at the dominant

55、 position in the control domain. Is standard PC is not but designs based on the PC control main question for the strict industry environment.</p><p>　　PC mainly faces three major problems: </p><p&

56、gt;　　Stability: The usual PC general operating system cannot provide uses in controlling the enough stability. The installment can force the processing system collapse based on the PC control equipment and not expect to

57、again opens. </p><p>　　Reliability: Because PC has the magnetic hard disk and the non- reliable part which revolves, like the power source, this makes it to be easier to appear the breakdown. </p><

58、;p>　　Not familiar programming environment: The factory operator needs to have when maintains and fixes the breakdown restores the system the ability. The use trapezoidal logic, they may manual force the coil to restor

59、e to the perfect condition, and can fast patch the code which affects by is fast restored the system. However, the PC system needs the operator to study the new higher paraffin the tool.</p><p>　　Although ce

60、rtain engineers use have the firm hardware and the specially operating system special-purpose industry computer, but because Engineer PC reliable aspect question overwhelming majority avoids in the control using PC. In a

61、ddition, uses in each kind of automated duty equipment in PC, like I/O, correspondence, or movement possible need different development environment.</p><p>　　Therefore these must develop "20% applicatio

62、n" engineers either use PLC to be unable with ease to realize the function which the system needs, either uses both contains PLC and to contain PC the mix system, they use PLC to carry out the code control section,

63、realizes the higher paraffin function with PC. Thus the present many factories workshops use the system which PLC and PC unifies, in use system PC carries on the data record, the connection bar code scanner, inserts the

64、information in the da</p><p>　　Constructs a better controller </p><p>　　Because does not have suitable PC or the PLC solution, these need development complex application engineer on develops the

65、 new product with the control merchant close cooperation. They need the new product to be able to unify PC the senior software function and the PLC reliability. These important users were PLC and have provided the produc

66、t development instruction based on the PC control company.</p><p>　　Realizes the software function not only to need to have the senior the software, moreover the controller hardware function also needs to ha

67、ve the enhancement. Because in the world scope is dropping to the PC part demand, therefore many semiconductors merchants start for the industrial application redesign their product. At present controls the domain the me

68、rchant to start in the industry control product to use the industrialization floating point processor, DRAM, solid state memory like Compact </p><p>　　This kind of new controller is the solution "20%&qu

69、ot; the application question but designs, it unified PLC and the PC two merits. The ARC industry analyst is called this kind of equipment the programmable automated controller, namely PAC. "The programmable logical

70、controller world looks at in generally" the research in ARC, they have produced the PAC five principal characteristics. These controller characteristics are through define the software the ability to realize its fun

71、ction. </p><p>　　"Multi-purpose, has in the logic, the movement, the PID control, the actuation and processing in a platform at least two kind of above functions." Except that in order to realize s

72、pecial agreement like SERCOS to have to I/O makes some improvements; Moreover the software also can provide logical, the movement, processing and the PID function. For example, the movement control took the software cont

73、rol circulation, it can reading the digital input from the orthogonal encoder, the execution simulat</p><p>　　"The sole multi- regulations develop the platform use general label and the sole database vi

74、sit all parameters and the function." Because PAC is like multi-purpose but designs for more the senior application, they need the senior software. In order to can highly effective design the system, the software mu

75、st be the sole integrated software package, but is not the many kinds of separations software tool, these software tools in the project cannot the seamless joint operation. </p><p>　　"Through unifies IE

76、C61131-3, the user guide and the data management, the software tool can design is surmounting many machines and the processing unit processing flow." The simplification system design on the other hand is has the sen

77、ior the development kit, uses this tool to be possible to cause engineer very with ease to transform the processing concept for can actual control the machine the code. </p><p>　　"The opening modular sk

78、eleton can solve the industrial application may distribute from the control in the factory machine to processes workshop the operation unit." Because all industrial application all needs to have highly has custom-ma

79、de the characteristic, therefore the hardware must be the modulation in order to engineers may choose the appropriate part. Moreover, the software also must be able to let engineer increase and the demolition module by t

80、he system which designs needs. </p><p>　　"Uses already the network interface standard which has, the language and so on, like TCPIP, OPC&XML and SQL inquiry language." Can with enterprise's

81、 network correspondence regarding the modernization control system be extremely essential. Although PAC contains has the ethernet connection, but in order to must does not have the equipment and the factory other systems

82、 the question to integrate in together, corresponds the software is very important.</p><p>　　Two kind of different softwares solution</p><p>　　On the one hand the software is PAC and the PLC mai

83、n difference, but on the other hand the merchant in provides the senior software in the way also to differ from. Usually they the control software which has have taken the beginning by at present, increases the function,

84、 the reliability and the usability unceasingly which the PAC programming needs. In general, some two kinds provide the PAC software the way: Based on PLC control software and based on PC control software</p><p

85、>　　Based on PLC concept software plan</p><p>　　The traditional PLC software merchant take is reliable also Yi Yong scanning type overhead construction software as a beginning, and increases the new functi

86、on gradually. The PLC software basis general model but establishes: The input scanning, the control code movement, the input renews, as well as conventional function execution. As a result of the input circulation, the o

87、utput circulation and the conventional circulation all is the hideaway, therefore control engineer only must pay attention </p><p>　　Based on PC concept software plan</p><p>　　The traditional PC

88、 software merchant take the extremely nimble general programming language as a beginning, can provide to the hardware deep level visit. This kind of software also has the control overhead construction which the reliabili

89、ty, determinism as well as supposes in advance. Although engineer can be the PLC programmers establishes the scanning type skeleton, but it is not based on the PC software inherent. These cause the PC software to be extr

90、emely nimble, suits these need senior extr</p><p>　　These merchants first must be able to provide the reliability and determinism which general operating system like Windows does not have. They may through u

91、se the real-time operating system (RTOS) Tathagata realize from Ardence Phar Lap or Wind River VxWorks. These RTOS can control system each stratification plane, from I/O read-write speed to controller on each regulation

92、priority. Then in order to enable engineer easily to develop the reliable control procedure, the merchant increased the abstr</p><p>　　NI has developed can move LabVIEW procedure a series of PAC to deliver t

93、he platform. LabVIEW has become tests and surveys the software the fact standard. It has direct-viewing being similar in the flow chart programming way, and through is easy the contact surface which uses to provide all f

94、unctions which the senior programming language has. Using LabVIEW RT and LabVIEW FPGA, we can unify LabVIEW and the real-time operating system and download directly to FPGA (scene programmable gate array) the</p>

95、<p>　　Based on PAC vision and survey application</p><p>　　NI has the survey the profession background, it caused PAC through the introduction high speed survey and the machine vision to surmount simple

96、I/O. Needs high speed to gather the measurement result in many industrial applications by to use in vibrating or the power quality analysis. Gathers to the data uses for to monitor revolves the machinery condition, deter

97、mined the maintenance timetable, distinguishes the electrical machinery the attrition degree as well as the adjustment control algorithm</p><p>　　Engineers also may use the visual function in theirs control

98、system. In the past in ten years the vision obtained in the automated domain swiftly and violently has developed. In the production environment, some many products flaw or the wrong use tradition measuring technique is v

99、ery difficult to distinguish, but through visual way then can examine. The common application including uses in producing or the assembly examination components examination, like on test circuit board component position&

100、lt;/p><p>　　PAC has avoided regarding the special hardware need</p><p>　　PAC is representing the programmable controller newest technology, it future will develop the key will be decided in inserts

101、 the type technology the introduction. For instance must be able to define the hardware through the software. The electronic merchant often uses the chip which the scene programmable gate array (FPGA) such electronic dev