plc中英對照外文翻譯----可編程控制器技術(shù)討論與未來發(fā)展

1、<p>　　可編程控制器技術(shù)討論與未來發(fā)展</p><p>　　隨著時代的發(fā)展,當(dāng)今的技術(shù)也日趨完善、競爭愈演愈烈;單靠人工的操作已不能滿足于目前的制造業(yè)前景,也無法保證更高質(zhì)量的要求和高新技術(shù)企業(yè)的形象。</p><p>　　人們在生產(chǎn)實(shí)踐中看到,自動化給人們帶來了極大的便利和產(chǎn)品質(zhì)量上的保證,同時也減輕了人員的勞動強(qiáng)度,減少了人員上的編制.在許多復(fù)雜的生產(chǎn)過程中難以實(shí)現(xiàn)的目標(biāo)

2、控制、整體優(yōu)化、最佳決策等,熟練的操作工、技術(shù)人員或?qū)＜?、管理者卻能夠容易判斷和操作,可以獲得滿意的效果.人工智能的研究目標(biāo)正是利用計算機(jī)來實(shí)現(xiàn)、模擬這些智能行為,通過人腦與計算機(jī)協(xié)調(diào)工作,以人機(jī)結(jié)合的模式,為解決十分復(fù)雜的問題尋找最佳的途徑。</p><p>　　我們在各種場合看到了繼電器連接的控制，那已經(jīng)是時代的過去，如今的繼電器只能作為低端的基層控制模塊或者簡單的設(shè)備中使用到；而PLC的出現(xiàn)也成為了劃時代的

3、主題，通過極其穩(wěn)定的硬件穿插靈活的軟件控制，使得自動化走向了新的高潮。</p><p>　　PLC的最大特點(diǎn)在于：電氣工程師已不再電氣的硬件上花費(fèi)太多的心計，只要將按鈕開關(guān)或感應(yīng)器的輸入點(diǎn)連接到PLC的輸入點(diǎn)上就能解決問題，通過輸出點(diǎn)連接接觸器或繼電器來控制大功率的啟動設(shè)備，而小功率的輸出設(shè)備直接連接就可以。</p><p>　　PLC的內(nèi)部包含了具有中央處理器的CPU，并帶有外部I/O口

4、擴(kuò)展的I/O接口地址和存儲器三大塊組成，CPU的核心是由一個或者多個累加器組成，它們具有邏輯的數(shù)學(xué)運(yùn)算能力，并能讀取程序存儲器的內(nèi)容通過計算后去驅(qū)動相應(yīng)的存儲器和I/O接口；I/O口將內(nèi)部累加器和外部的輸入和輸出系統(tǒng)連接起來，并將相關(guān)的數(shù)據(jù)存入程序存儲器或者數(shù)據(jù)存儲器中；存儲器可以將I/O口輸入的數(shù)據(jù)存入存儲器中，并在工作時調(diào)轉(zhuǎn)到累加器和I/O接口上，存儲器分程序存儲器ROM和數(shù)據(jù)存儲器RAM,ROM可以將數(shù)據(jù)永久的存入存儲器中，而RA

5、M只能作為CPU計算時臨時計算使用的緩沖空間。</p><p>　　PLC的抗干擾是極其優(yōu)秀的，我們根本不用去關(guān)心它的使用壽命和工作場合的惡劣，這些所有的問題已不再成為我們失敗的主題，而留給我們的是關(guān)心如何來利用PLC的內(nèi)部資源為我們加強(qiáng)設(shè)備的控制能力，使我們的設(shè)備更加的柔性。</p><p>　　PLC的語言并不是我們所想象的匯編語言或C語言來進(jìn)行編程，而是采用原有的繼電器控制的梯形圖，

6、使得電氣工程師在編寫程序時很容易就理解了PLC的語言，而且很多的非電氣專業(yè)人士也對PLC很快認(rèn)識并深入。</p><p>　　以上僅僅是PLC的優(yōu)點(diǎn)之一，這也是人們比較容易理解的一部分，在很多的設(shè)備中，人們已不再希望看到太多的控制按鈕，它們不但容易損壞而且極易產(chǎn)生人為的失誤，小的并不是主要的失誤也許你還能夠接受；但過大的甚至是致命的失誤是我們無法容忍的。新的技術(shù)總是為了給我們帶來更安全和便捷的操作，使得我們面臨的

7、一大堆問題一掃而光，你有了解過HMI嗎？這里說HMI你根本不清楚它是什么，也沒有興趣了解，換一個中文把它說明為觸摸屏或者人機(jī)界面你就知道了，它和PLC的結(jié)合給了我們更大的空間。</p><p>　　HMI控制不僅僅是減少了控制按鈕，增加控制的靈活性，更主要的它是可順序性的，而且在能夠改變數(shù)據(jù)輸入和數(shù)據(jù)輸出反饋，在溫度控制曲線的模擬也能直觀的顯示出來。并且能夠通過編寫功能幫助程序來提供各種力所能及的幫助，使得操作者

8、減少不必要的失誤。HMI的廠商目前也越來越多，功能也越來越強(qiáng)，價格也越來越低，使用的面越來越廣。HMI的前景可以說十分的看好。</p><p>　　在很多場合，單靠單機(jī)的控制是無法保證設(shè)備的順暢運(yùn)行，而通過設(shè)備與設(shè)備的信息交流達(dá)到我們想要的效果。比如在前包裝和后工序的檢測，我們就要將包裝的信息反饋到檢測處，而檢測處的信息也要反饋到包裝來。這樣通過信息共享來使得兩者之間鏈接起來，形成一個共體，從而使的兩者間的配合更

9、加的緊密，在彼此間達(dá)到映影相揮的效果。</p><p>　　PLC的通信已經(jīng)愈來愈體現(xiàn)它的價值，在PLC與PLC之間的通信，能夠通過信息的溝通和數(shù)據(jù)的共享來保證設(shè)備之間的相互協(xié)調(diào)，已達(dá)到互補(bǔ)的效果。PLC之間的數(shù)據(jù)轉(zhuǎn)換采用RS232接口來傳送數(shù)據(jù)，而RS232接口只能保證10米的傳輸距離，如果在1000米的距離內(nèi)我們可以通過RS485來進(jìn)行通信，更長的距離只能通過MODEL來進(jìn)行傳輸。</p>&l

10、t;p>　　PLC的數(shù)據(jù)傳送只是將內(nèi)部的數(shù)據(jù)傳送到對方的一塊連續(xù)的地址中，我們把它稱為一個表，對方的PLC通過讀取表中的數(shù)據(jù)來進(jìn)行操作。如果表中的數(shù)據(jù)是一個一般設(shè)置的數(shù)據(jù)的話，那只是一般的數(shù)據(jù)傳送，比如今天的油價上升了，我要把油價的價格傳送到所有的輸油機(jī)上，那就是數(shù)據(jù)的共享；而當(dāng)表中的數(shù)據(jù)是一段控制PLC的指令程序，那就很有難度了，比如你要控制一臺機(jī)器人來按你想象的動作工作，你會給它編制一段程序并以數(shù)據(jù)的形式發(fā)送過去。</p

11、><p>　　信息輸送的形式有單工位、半雙工位和全雙工位的分別。單工位的意義也就是說兩者之間，一個只能發(fā)送，而一個只能接收，比如一個特務(wù)他只能接收上司的指示，而無法給上司回復(fù)；半雙工位也就是兩個能都能發(fā)送和接受數(shù)據(jù)，但不能同時發(fā)送和接受，比如你打電話時是不能接電話,對方也一樣；而全雙工位是兩者之間都能發(fā)送和接受數(shù)據(jù)，并可同時發(fā)送和接受。像互聯(lián)網(wǎng)就是典型的例子。</p><p>　　信息輸送的過

12、程也有同步和異步之分：同步的意義在于發(fā)送數(shù)據(jù)時數(shù)據(jù)線和時鐘線是同步的，也就是數(shù)據(jù)信號和時鐘信號同時由CPU進(jìn)行發(fā)送，這需要彼此都要專門的時鐘信號來進(jìn)行傳送和接送，并且是強(qiáng)制性的，這種方法的特點(diǎn)在于它的速度極快、但相應(yīng)占用CPU的工作時間也相對的要長、同時技術(shù)難度也非常的大。它的要求在于在一幀的數(shù)據(jù)傳送中不能有一位的誤差，不然的話整個數(shù)據(jù)將發(fā)生錯誤，這在硬件上是一個比較大的難度。在一些專用的設(shè)備中應(yīng)用的越來越廣泛，像專用的醫(yī)療設(shè)備、數(shù)字信

13、號設(shè)備等，在比較單一數(shù)據(jù)的傳輸中，它的效果非常的好。</p><p>　　而異步是應(yīng)用范圍最廣泛的，這得益于它的技術(shù)難度相對要小、同時不需要配制專門的時鐘信號、它的特點(diǎn)在于，它的數(shù)據(jù)是間隔性的，離散性的發(fā)送和接受，當(dāng)CPU太忙的時候可以停頓性去工作，在硬件上也減少了難度，同時數(shù)據(jù)的丟失相對要少，我們可以通過數(shù)據(jù)的檢測來觀察我們發(fā)送的數(shù)據(jù)是否有錯誤，像奇偶法、累加法和八位效驗(yàn)法等，都可以用來幫助我們檢測發(fā)送的數(shù)據(jù)是

14、否有錯誤發(fā)生，通過反饋來進(jìn)行辨別。</p><p>　　信息的傳送口線有串口和并口之分：通常的PLC是8位機(jī)，當(dāng)然也有16位機(jī)。我們在發(fā)送數(shù)據(jù)的時候可以是一位一位的發(fā)送給對方，也可以8位8位的將數(shù)據(jù)發(fā)送到對方，一位和8位區(qū)別也就是我們所說的串口發(fā)送數(shù)據(jù)和并口發(fā)送數(shù)據(jù)。串口速度比較慢，但只要兩條或者三條口線就能解決問題，并能借用電話線來進(jìn)行遠(yuǎn)程控制。而并口的傳送速度是極快的，它是串口的256倍，在短距離占有優(yōu)勢，由

15、于是TTL電平，一般限于1米的范圍，它并不適用于長距離的數(shù)據(jù)傳送，這樣成本太昂貴了。</p><p>　　很多的情況下我們總喜歡采用串并轉(zhuǎn)換芯片來進(jìn)行傳輸，這種情況下不需要我們進(jìn)行過于復(fù)雜的寄存器設(shè)置了，而直接通過數(shù)據(jù)傳送指令進(jìn)行數(shù)據(jù)交流，但在通信中并不是一個十分可行的辦法，因?yàn)樵诎l(fā)送數(shù)據(jù)的時候?qū)Ψ降腜LC必須一直等待你的數(shù)據(jù)輸出，它不能去做其他的工作。</p><p>　　當(dāng)你在看書的時

16、候，你聽到有人敲門、你停下手上的事情、去打開門、并同敲門者對話、這個時候電話響了、你示意接個電話、在接完電話后、回過頭來同敲門者繼續(xù)對話、對話完畢后、你再繼續(xù)看你的書，這種情況我們把它稱為中斷，它具有權(quán)威性，也具有優(yōu)先性，PLC具備了這樣的功能。它的特點(diǎn)在于我們在設(shè)備的操作過程中可能會遇到緊急的突發(fā)事件，我們要立刻的停下手上的工作，去處理更重要的事情，這種情況是我們經(jīng)常所遇到的，PLC在去執(zhí)行緊急的任務(wù)時，總會先保存目前的狀態(tài)，比如程序

17、的地址，CPU的累加器數(shù)據(jù)等，就像我們?nèi)ラ_門時要記下我們看的書在第幾頁了或者干脆作個記號，因?yàn)槲覀兇龝€要繼續(xù)接著看后面的書。CPU總是按照我們的意愿去做應(yīng)該做的事情，但你錯誤的給它一件事情，它也會同樣的去做，這一點(diǎn)我們必須注意。</p><p>　　中斷并不是只有一個，有時會同時存在幾個中斷，中斷具有優(yōu)先的級別，他們會根據(jù)人的要求去執(zhí)行更高級別的中斷。這種中斷中的中斷也就形成了中斷嵌套。當(dāng)然中斷的級別根據(jù)各種P

18、LC內(nèi)部CPU的資源有關(guān)，同時也跟堆棧的容量大小也有關(guān)系。</p><p>　　中斷的內(nèi)容有很多種，比如外部中斷、通信中的發(fā)送和接受中斷、定時和計數(shù)的時鐘中斷、還有WDT復(fù)位中斷等，它們豐富了CPU在處理各種事務(wù)時響應(yīng)種類。這樣講也許你并不能完全理解中斷的內(nèi)部結(jié)構(gòu)和操作順序，我們做一個小小的例子來說明。</p><p>　　每一個設(shè)備總是不會忘記有一個按鈕，它也是在我們遇到緊急情況時使用的

19、，那就是急停按鈕。當(dāng)我們遇到人身事故和意外情況時我們只要按下它，機(jī)器立即停止所有的操作，并等待處理完意外后再恢復(fù)操作。急停按鈕連接PLC內(nèi)部CPU的內(nèi)部I/O接口上，當(dāng)按鈕給CPU一個外部觸發(fā)信號時，CPU對I/O進(jìn)行再次檢測，當(dāng)確認(rèn)有外部觸發(fā)信號時，CPU保護(hù)現(xiàn)場并將程序計數(shù)器自動轉(zhuǎn)到相應(yīng)的外部I/O中斷程序中去，當(dāng)外部中斷程序處理完畢，程序計數(shù)器返回到主程序繼續(xù)工作。有一點(diǎn)可以說明的是我們一般會把急停按鈕的外部中斷升至最高級別，從而

20、保證安全。</p><p>　　當(dāng)我們在工作完一個工件時，給PLC一個信號，將PLC的內(nèi)部計數(shù)器加1來計算我們一天的工作量時，一個簡單的計數(shù)器能解決問題，當(dāng)然它們也能夠在掉電的情況下保持?jǐn)?shù)據(jù)，促使數(shù)據(jù)不丟失，這也是我們所渴望的。</p><p>　　PLC還具有高級計數(shù)器的功能，當(dāng)我們在接受一些高速的數(shù)據(jù)時，這里所說的高速是在在微秒級的數(shù)據(jù)，比如條碼掃描機(jī)在不斷的掃描數(shù)據(jù)，數(shù)據(jù)處理器DSP

21、計算的高速信號等，我們就要采用到高級計數(shù)器來幫助我們進(jìn)行計數(shù)。它在PLC執(zhí)行程序時一旦發(fā)現(xiàn)高級計數(shù)器對應(yīng)的中斷，就會立即放下手上的工作。經(jīng)過再次編程的梯形圖程序說明我們在執(zhí)行程序時高級計數(shù)器會自動的執(zhí)行對應(yīng)的工作，從而將高級計數(shù)器的級別升至高一級別。</p><p>　　你也許聽過太多的這個詞:“死機(jī)”，大致的意思是CPU工作量過大，內(nèi)部資源不足等情況造成程序無法運(yùn)行。PLC也有類似的情況，在PLC內(nèi)部有一個看門

22、狗WDT，我們可以設(shè)置WDT一個程序運(yùn)行的時間，當(dāng)程序運(yùn)行過程中出現(xiàn)程序跳轉(zhuǎn)錯誤時或者程序繁忙時，程序的運(yùn)行時間超過WDT的設(shè)置時間，CPU轉(zhuǎn)而WDT復(fù)位狀態(tài)。程序重新開始運(yùn)行，但對中斷不會進(jìn)行破壞。</p><p>　　PLC的發(fā)展已經(jīng)從單一的模式進(jìn)入了通信的網(wǎng)絡(luò)時代，并同其它的工控網(wǎng)板和I/O卡板輕易的進(jìn)行共享。組態(tài)軟件可以將所有的這些硬件連接起來，通過更直觀的動畫圖片來進(jìn)行控制，并可以通過互聯(lián)網(wǎng)在異地進(jìn)行控

23、制，像神舟五號的發(fā)射就是采用這種辦法來使飛船升空。</p><p>　　更高層次的發(fā)展需要我們不斷的努力來取得。PLC的出現(xiàn)已經(jīng)足足影響了幾代人，我們也從上一輩的經(jīng)驗(yàn)中獲取了更多的知識和教訓(xùn)，來不斷的發(fā)展PLC技術(shù)，將它推向更高浪潮。</p><p>　　PLC technique discussion and future development</p><p>

24、　　Along with the development of the ages, the technique that is nowadays is also gradually perfect, the competition plays more and more strong; the operation that list depends the artificial has already can't satisfi

25、ed with the current manufacturing industry foreground, also can't guarantee the request of the higher quantity and high new the image of the technique business enterprise.</p><p>　　The people see in prod

26、uce practice, automate brought the tremendous convenience and the product quantities for people up of assurance, also eased the personnel's labor strength, reduce the establishment on the personnel. The target contro

27、l of the hard realization in many complicated production lines, whole and excellent turn, the best decision etc., well-trained operation work, technical personnel or expert, governor but can judge and operate easily, can

28、 acquire the satisfied result. The researc</p><p>　　We come in sight of the control that links after the electric appliances in various situation, that is already the that time generation past, now of after

29、use in the mold a perhaps simple equipments of grass-roots control that the electric appliances can do for the low level only; And the PLC emergence also became the epoch-making topic, adding the vivid software control t

30、hrough a very and stable hardware, making the automation head for the new high tide.</p><p>　　The PLC biggest characteristics lie in: The electrical engineering teacher already no longer electric hardware up

31、 too many calculations of cost, as long as order the importation that the button switch or the importation of the sensors order to link the PLC up can solve problem, pass to output to order the conjunction contact machin

32、e or control the start equipments of the big power after the electric appliances, but the exportation equipments direct conjunction of the small power can.</p><p>　　PLC internal containment have the CPU of t

33、he CPU, and take to have an I/ O for expand of exterior to connect a people's address and saving machine three big pieces to constitute, CPU core is from an or many is tired to add the machine to constitute, mathemat

34、ics that they have the logic operation ability, and can read the procedure save the contents of the machine to drive the homologous saving machine and I/ Os to connect after pass the calculation; The I/ O add inner part

35、is tired the input and</p><p>　　The PLC anti- interference is very and excellent, our root need not concern its service life and the work situation bad, these all problems have already no longer become the t

36、opic that we fail, but stay to our is a concern to come to internal resources of make use of the PLC to strengthen the control ability of the equipments for us, make our equipments more gentle.</p><p>　　PLC

37、language is not we imagine of edit collected materials the language or language of Cs to carry on weaving the distance, but the trapezoid diagram that the adoption is original after the electric appliances to control, ma

38、ke the electrical engineering teacher while weaving to write the procedure very easy comprehended the PLC language, and a lot of non- electricity professional also very quickly know and go deep into to the PLC.</p>

39、<p>　　Is PLC one of the advantage above and only, this is also one part that the people comprehend more and easily, in a lot of equipments, the people have already no longer hoped to see too many control buttons,

40、they damage not only and easily and produce the artificial error easiest, small is not a main error perhaps you can still accept; But lead even is a fatal error greatly is what we can't is tolerant of. New technique

41、always for bringing more safe and convenient operation for us, make we a lot </p><p>　　HMI the control not only is reduced the control press button, increase the vivid of the control, more main of it is can

42、sequence of, and at can the change data input to output the feedback with data, control in the temperature curve of imitate but also can keep the manifestation of view to come out. And can write the function help procedu

43、re through a plait to provide the help of various what lies in one's power, the one who make operate reduces the otiose error. Currently the HMI factory is also</p><p>　　At a lot of situations, the list

44、is a smooth movement that can't guarantee the equipments by the control of the single machine, but pass the information exchanges of the equipments and equipments to attain the result that we want. For example fore p

45、ack and the examination of the empress work preface, we will arrive wrapping information feedback to examine the place, and examine the information of the place to also want the feedback to packing. Pass the information

46、share thus to make both the cha</p><p>　　The PLC correspondence has already come more body now its value, at the PLC and correspondence between PLC can pass the communication of the information and the share

47、 of the data’s to guarantee that of the equipments moderates mutually, the result that arrive already to repair with each other. Data conversion the adoption RS232 between PLC connect to come to the transmission data, bu

48、t the RS232 pick up a people and can guarantee 10 meters only of deliver the distance, if in the distance of 1000 </p><p>　　The PLC data transmission is just to be called a form to it in a piece of and conti

49、nuous address that the data of the inner part delivers the other party, we, the PLC of the other party passes to read data in the watch to carry on the operation. If the data that data in the watch is a to establish gene

50、rally, that is just the general data transmission, for example today of oil price rise, I want to deliver the price of the oil price to lose the oil ally on board, that is the share of the data; Bu</p><p>　　

51、The form that information transport contain single work, the half a work and the difference of a work .The meaning of the single work also is to say both, a can send out only, but a can receive only, for example a spy he

52、 can receive the designation of the superior only, but can't give the superior reply; A work of half is also 2 and can can send out similar to accept the data, but can't send out and accept at the same time, for

53、example when you make a phone call is to can't answer the phone, the</p><p>　　The process that information transport also has synchronous and different step cent: The data line and the clock lines are sy

54、nchronous when synchronous meaning lie in sending out the data, is also the data signal and the clock signals to be carry on by the CPU to send out at the same time, this needs to all want the specialized clock signal ea

55、ch other to carry on the transmission and connect to send, and is constrained, the characteristics of this kind of method lies in its speed very quick, but</p><p>　　And the different step is an application t

56、he most extensive, this receive benefit in it of technique difficulty is opposite and want to be small, at the same time not need to prepare the specialized clock signal, its characteristics to lie in, its data is partit

57、ion, the long-lost send out and accept, be the CPU is too busy of time can grind to a stop sex to work, also reduced the difficulty on the hardware, the data throw to lose at the same time opposite want to be little, we

58、can pass the exami</p><p>　　A line of transmission of the information contains a string of and combines the cent of: The usual PLC is 8 machines, certainly also having 16 machines. We can be an at the time o

59、f sending out the data a send out to the other party, also can be 88 send out the data to the other party, an and 8 differentiations are also the as that we say to send out the data and combine sends out the data. A spee

60、d is more and slowly, but as long as 2 or three lines can solve problem, and can use the telephone li</p><p>　　Under a lot of circumstances we are total to like to adopt the string to combine the conversion

61、chip to carry on deliver, under this kind of circumstance not need us to carry on to deposited the machine to establish too and complicatedly, but carry on the data exchanges through the data transmission instruction dir

62、ectly, but is not a very viable way in the correspondence, because the PLC of the other party must has been wait for your data exportation at the time of sending out the data, it can't</p><p>　　When you

63、are reading the book, you hear someone knock on door, you stop to start up of affair, open the door and combine to continue with the one who knock on door a dialogue, the telephone of this time rang, you signal hint to c

64、onnect a telephone, after connecting the telephone through, return overdo come together knock on door to have a conversation, after dialogue complete, you continue again to see your book, this kind of circumstance we are

65、 called the interruption to it, it has the authorit</p><p>　　The interruption is not only a, sometimes existing jointly with the hour several inside break, break off to have the preferred Class, they will ca

66、rry out the interruption of the higher Class according to person's request. This kind of breaks off the medium interruption to also became to break off the set. The Class that certainly break off is relevant accordin

67、g to various resources of CPU with internal PLC, also following a heap of capacity size of also relevant fasten.</p><p>　　The contents that break off has a lot of kinds, for example the exterior break off, c

68、orrespondence in of send out and accept the interruption and settle and the clock that count break off, still have the WDT to reset the interruption etc., they enriched the CPU to respond to the category while handle var

69、ious business. Speak thus perhaps you can't comprehend the internal structure and operation orders of the interruption completely also, we do a very small example to explain.</p><p>　　Each equipment alwa

70、ys will not forget a button, it also is at we meet the urgent circumstance use of that is nasty to stop the button. When we meet the Human body trouble and surprised circumstances we as long as press it, the machine stop

71、s all operations immediately, and wait for processing the over surprised empress recover the operation again. Nasty stop the internal I/ O of the internal CPU of the button conjunction PLC to connect up, be to press butt

72、on an exterior to trigger signal for CPU,</p><p>　　When we are work a work piece, giving the PLC a signal, counting PLC inner part the machine add 1 to compute us for a day of workload, a count the machine a

73、nd can solve problem in brief, certainly they also can keep the data under the condition of dropping the electricity, urging the data not to throw to lose, this is also what we hope earnestly.</p><p>　　The P

74、LC still has the function that the high class counts the machine, being us while accept some data’s of high speed, the high speed that here say is the data of the in all aspects tiny second class, for example the bar cod

75、e scanner is scanning the data continuously, calculating high-speed signal of the data processor DSP etc., we will adopt the high class to count the machine to help we carry on count. It at the PLC carries out the proced

76、ure once discover that the high class counts the machin</p><p>　　You heard too many this phrases perhaps:" crash", the meaning that is mostly is a workload of CPU to lead greatly, the internal reso

77、urces shortage etc. the circumstance can't result in procedure circulate. The PLC also has the similar circumstance, there is a watchdog WDT in the inner part of PLC, we can establish time that a procedure of WDT cir

78、culate, being to appear the procedure to jump to turn the mistake in the procedure movement process or the procedure is busy, movement time of the proce</p><p>　　The PLC development has already entered for n

79、etwork ages of correspondence from the mode of the one, and together other works control the net plank and I/ O card planks to carry on the share easily. A state software can pass all se hardware’s link, more animation p

80、icture of keep the view to carries on the control, and cans pass the Internet to carry on the control in the foreign land, the blast-off that is like the absolute being boat No.5 is to adopt this kind of way to make airs

81、hip go up the s</p><p>　　The development of the higher layer needs our continuous effort to obtain. The PLC emergence has already affected a few persons fully, we also obtained more knowledge and precepts fr