plc中英文資料外文翻譯---可編程控制器技術(shù)討論與未來(lái)發(fā)展

1、<p><b>　　附錄</b></p><p><b>　　外文資料</b></p><p>　　PLC technique discussion and future development</p><p>　　Along with the development of the ages, the techn

2、ique that is nowadays is also gradually perfect, the competition plays more more strong; the operation that list depends the artificial has already can't satisfied with the current manufacturing industry foreground,

3、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 produce practice, automate brought the tremendous convenien

4、ce and the product quantities for people up of assurance, also eased the personnel's labor strength, reduce the establishment on the personnel. The target control of the hard realization in many complicated productio

5、n 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 acquire the satisfied result. The researc</p>&

6、lt;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 use in the mold a perhaps simple equipments of grass-ro

7、ots 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 through a very and stable hardware, making the automation

8、 head for the new high tide.</p><p>　　The PLC biggest characteristics lie in: The electrical engineering teacher already no longer electric hardware up too many calculationses of cost, as long as order the i

9、mportation 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 machine or control the start equipments of the big power aft

10、er the electric appliances, but the exportation equipments direct conjunction of the small power can.</p><p>　　PLC internal containment have the CPU of the CPU, and take to have an I/ O for expand of exterio

11、r 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, mathematics that they have the logic operation ability, and ca

12、n 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 is tired the input and</p><p>　　The PLC a

13、nti- 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 topic that we fail, but stay to our is a concern to com

14、e 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 language is not we imagine of edit collected materials

15、 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, make the electrical engineering teacher while weaving to

16、 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><p>　　Is PLC one of the advantage above and onl

17、y, this is also one part that the people comprehend more and easily, in a lot of equipmentses, the people have already no longer hoped to see too many control buttons, they damage not only and easily and produce the arti

18、ficial 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 always for bringing more safe and convenient operati

19、on for us, make we a lo</p><p>　　HMI the control not only only is reduced the control press button, increase the vivid of the control, more main of it is can sequence of, and at can the change data input to

20、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 procedure through a plait to provide the help of various

21、 what lies in one's power, the one who make operate reduces the otiose error. Currently the HMI factory is</p><p>　　At a lot of situations, the list is is a smooth movement that can't guarantee the e

22、quipments 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 pack and the examination of the empress work preface

23、, 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 share thus to make both the </p><p>　　

24、The PLC correspondence has already come more more body now its value, at the PLC and correspondence between PLCs, can pass the communication of the information and the share of the datas to guarantee that of the equipmen

25、ts 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, but the RS232 pick up a people and can guarantee 1

26、0 meters only of deliver the distance, if in the distance of</p><p>　　The PLC data transmission is just to be called a form to it in a piece of and continuous address that the data of the inner part delivers

27、 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 generally, that is just the general data transmission, for

28、 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>　　The form that information transport contain single wor

29、k, the half a work and the difference of a workses .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 can receive the designation of the superior only,

30、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 example when you make a phone call is to can't

31、answer the phone, </p><p>　　The process that information transport also has synchronous and different step cent: The data line and the clock lines are synchronous when synchronous meaning lie in sending out

32、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 each other to carry on the transmission and connect to s

33、end, 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 the most extensive, this receive benefit in it of techn

34、ique 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 partition, the long-lost send out and accept, be the CPU is

35、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 can pass the exami</p><p>　　A line of tra

36、nsmission of the information contain a string of and combine the cent of: The usual PLC is 8 machines, certainly also having 16 machines. We can be an at the time of sending out the data a send out to the other party, al

37、so can be 88 send out the data to the other party, an and 8 differentiationses are also the as that we say to send out the data and combine sends out the data. A speed is more and slowly, but as long as 2 or three lines

38、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 chip to carry on deliver, under this kind of circumsta

39、nce not need us to carry on to depositted the machine to establish too and complicatedly, but carry on the data exchanges through the data transmission instruction directly, but is not a very viable way in the correspond

40、ence, 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'</p><p>　　When you are reading the book, you hear someone knock on door,

41、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 connect a telephone, after connecting the telephone thr

42、ough, 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 called the interruption to it, it has the authorit<

43、;/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 carry out the interruption of the higher Class according

44、 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 according to various resources of CPU with internal PLC, also

45、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, correspondence in of send out and accept the interrupti

46、on 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 various business. Speak thus perhaps you can't compre

47、hend the internal structure and operation orders of the interruption completely also, we do a very small example to explain.</p><p>　　Each equipments always will not forget a button, it also is at we meet th

48、e 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 stops all operations immediately, and wait for processin

49、g 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 button an exterior to trigger signal for CPU</p>&

50、lt;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 and can solve problem in brief, certainly they also can

51、 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 PLC still has the function that the high class counts t

52、he machine, being us while accept some datas of high speed, the high speed that here say is the data of the in all aspects tiny second class, for example the bar code scanner is scanning the data continuously, calculatin

53、g 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 procedure once discover that the high class counts the machin

54、e</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 resources shortage etc. the circumstance can't result

55、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 circulate, being to appear the procedure to jump to turn

56、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 network ages of correspondence from the mode of the one

57、, 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 hardwares link, more animation picture of keep the view to carries on the control, and

58、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 airship go up the sk</p><p>　　The development

59、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 from the top one experience of the generation, coming to

60、 the continuous development PLC technique, push it toward higher wave tide.</p><p><b>　　中文翻譯</b></p><p>　　可編程控制器技術(shù)討論與未來(lái)發(fā)展</p><p>　　隨著時(shí)代的發(fā)展,當(dāng)今的技術(shù)也日趨完善、競(jìng)爭(zhēng)愈演愈烈;單靠人工的操作已不能滿

61、足于目前的制造業(yè)前景,也無(wú)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?cè)谏a(chǎn)實(shí)踐中看到,自動(dòng)化給人們帶來(lái)了極大的便利和產(chǎn)品質(zhì)量上的保證,同時(shí)也減輕了人員的勞動(dòng)強(qiáng)度,減少了人員上的編制.在許多復(fù)雜的生產(chǎn)過(guò)程中難以實(shí)現(xiàn)的目標(biāo)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(jì)算機(jī)來(lái)實(shí)現(xiàn)、模擬這些智能行為,通過(guò)人腦

62、與計(jì)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(wèn)題尋找最佳的途徑</p><p>　　我們?cè)诟鞣N場(chǎng)合看到了繼電器連接的控制，那已經(jīng)是時(shí)代的過(guò)去，如今的繼電器只能作為低端的基層控制模塊或者簡(jiǎn)單的設(shè)備中使用到；而PLC的出現(xiàn)也成為了劃時(shí)代的主題，通過(guò)極其穩(wěn)定的硬件穿插靈活的軟件控制，使得自動(dòng)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

63、的心計(jì)，只要將按鈕開(kāi)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(wèn)題，通過(guò)輸出點(diǎn)連接接觸器或繼電器來(lái)控制大功率的啟動(dòng)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口擴(kuò)展的I/O接口地址和存儲(chǔ)器三大塊組成，CPU的核心是由一個(gè)或者多個(gè)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(chǔ)器的內(nèi)容通過(guò)計(jì)算后去驅(qū)動(dòng)相應(yīng)的存儲(chǔ)器和I/O接口；

64、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(lái)，并將相關(guān)的數(shù)據(jù)存入程序存儲(chǔ)器或者數(shù)據(jù)存儲(chǔ)器中；存儲(chǔ)器可以將I/O口輸入的數(shù)據(jù)存入存儲(chǔ)器中，并在工作時(shí)調(diào)轉(zhuǎn)到累加器和I/O接口上，存儲(chǔ)器分程序存儲(chǔ)器ROM和數(shù)據(jù)存儲(chǔ)器RAM,ROM可以將數(shù)據(jù)永久的存入存儲(chǔ)器中，而RAM只能作為CPU計(jì)算時(shí)臨時(shí)計(jì)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(chǎng)合的惡劣，這些所

65、有的問(wèn)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(lái)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(yǔ)言并不是我們所想象的匯編語(yǔ)言或C語(yǔ)言來(lái)進(jìn)行編程，而是采用原有的繼電器控制的梯形圖，使得電氣工程師在編寫程序時(shí)很容易就理解了PLC的語(yǔ)言，而且很多的非電氣專業(yè)人士也對(duì)PLC很快認(rèn)識(shí)并深入。</p><p>　　以上僅僅是PLC的優(yōu)點(diǎn)之

66、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(guò)大的甚至是致命的失誤是我們無(wú)法容忍的。新的技術(shù)總是為了給我們帶來(lái)更安全和便捷的操作，使得我們面臨的一大堆問(wèn)題一掃而光，你有了解過(guò)HMI嗎？這里說(shuō)HMI你根本不清楚它是什么，也沒(méi)有興趣了解，換一個(gè)中文把它說(shuō)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

67、。</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(lái)。并且能夠通過(guò)編寫功能幫助程序來(lái)提供各種力所能及的幫助，使得操作者減少不必要的失誤。HMI的廠商目前也越來(lái)越多，功能也越來(lái)越強(qiáng)，價(jià)格也越來(lái)越低，使用的面越來(lái)越廣。HMI的前景可以說(shuō)十分的看好。</p><p>　　在

68、很多場(chǎng)合，單靠單機(jī)的控制是無(wú)法保證設(shè)備的順暢運(yùn)行，而通過(guò)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(cè)，我們就要將包裝的信息反饋到檢測(cè)處，而檢測(cè)處的信息也要反饋到包裝來(lái)。這樣通過(guò)信息共享來(lái)使得兩者之間鏈接起來(lái)，形成一個(gè)共體，從而使的兩者間的配合更加的緊密，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(lái)愈體現(xiàn)它的價(jià)值，在PLC與PLC之間的通信，能夠通過(guò)信息的溝通和數(shù)據(jù)的

69、共享來(lái)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(lái)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(guò)RS485來(lái)進(jìn)行通信，更長(zhǎng)的距離只能通過(guò)MODEL來(lái)進(jìn)行傳輸。</p><p>　　PLC的數(shù)據(jù)傳送只是將內(nèi)部的數(shù)據(jù)傳送到對(duì)方的一塊連續(xù)的地址中，我們把它稱為一個(gè)表，對(duì)方的PLC通過(guò)讀取表中的數(shù)據(jù)來(lái)進(jìn)行操作。如果表中的數(shù)據(jù)是一個(gè)一般設(shè)置的數(shù)

70、據(jù)的話，那只是一般的數(shù)據(jù)傳送，比如今天的油價(jià)上升了，我要把油價(jià)的價(jià)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(tái)機(jī)器人來(lái)按你想象的動(dòng)作工作，你會(huì)給它編制一段程序并以數(shù)據(jù)的形式發(fā)送過(guò)去。</p><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(shuō)兩者之間，一個(gè)只能發(fā)送，而一個(gè)只能接收，比如一個(gè)特務(wù)他只能接收上司的指

71、示，而無(wú)法給上司回復(fù)；半雙工位也就是兩個(gè)能都能發(fā)送和接受數(shù)據(jù)，但不能同時(shí)發(fā)送和接受，比如你打電話時(shí)是不能接電話,對(duì)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(shí)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(guò)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(shí)數(shù)據(jù)線和時(shí)鐘線是同步的，也就是數(shù)據(jù)信號(hào)和時(shí)鐘信號(hào)同時(shí)由CPU進(jìn)行發(fā)送，這需要彼此都要專門的時(shí)鐘信號(hào)來(lái)進(jìn)行傳送和接送，并且是強(qiáng)制性

72、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(shí)間也相對(duì)的要長(zhǎng)、同時(shí)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(gè)數(shù)據(jù)將發(fā)生錯(cuò)誤，這在硬件上是一個(gè)比較大的難度。在一些專用的設(shè)備中應(yīng)用的越來(lái)越廣泛，像專用的醫(yī)療設(shè)備、數(shù)字信號(hào)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(duì)要小、同時(shí)不需要配制專門的

73、時(shí)鐘信號(hào)、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(shí)候可以停頓性去工作，在硬件上也減少了難度，同時(shí)數(shù)據(jù)的丟失相對(duì)要少，我們可以通過(guò)數(shù)據(jù)的檢測(cè)來(lái)觀察我們發(fā)送的數(shù)據(jù)是否有錯(cuò)誤，像奇偶法、累加法和八位效驗(yàn)法等，都可以用來(lái)幫助我們檢測(cè)發(fā)送的數(shù)據(jù)是否有錯(cuò)誤發(fā)生，通過(guò)反饋來(lái)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?cè)诎l(fā)送數(shù)據(jù)的時(shí)候可

74、以是一位一位的發(fā)送給對(duì)方，也可以8位8位的將數(shù)據(jù)發(fā)送到對(duì)方，一位和8位區(qū)別也就是我們所說(shuō)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(wèn)題，并能借用電話線來(lái)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(shì)，由于是TTL電平，一般限于1米的范圍，它并不適用于長(zhǎng)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(lái)進(jìn)行

75、傳輸，這種情況下不需要我們進(jìn)行過(guò)于復(fù)雜的寄存器設(shè)置了，而直接通過(guò)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(gè)十分可行的辦法，因?yàn)樵诎l(fā)送數(shù)據(jù)的時(shí)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(shí)候，你聽(tīng)到有人敲門、你停下手上的事情、去打開(kāi)門、并同敲門者對(duì)話、這個(gè)時(shí)候電話響了、你示意接個(gè)電話、在接完電話后、回過(guò)頭來(lái)同敲門者繼續(xù)對(duì)話、對(duì)話完畢后、你再繼續(xù)看你的書，這種情

76、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?cè)谠O(shè)備的操作過(guò)程中可能會(huì)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(shí)，總會(huì)先保存目前的狀態(tài)，比如程序的地址，CPU的累加器數(shù)據(jù)等，就像我們?nèi)ラ_(kāi)門時(shí)要記下我們看的書在第幾頁(yè)了或者干脆作個(gè)記號(hào)，因?yàn)槲覀兇龝?huì)還要繼續(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(cuò)

77、誤的給它一件事情，它也會(huì)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(gè)，有時(shí)會(huì)同時(shí)存在幾個(gè)中斷，中斷具有優(yōu)先的級(jí)別，他們會(huì)根據(jù)人的要求去執(zhí)行更高級(jí)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(jí)別根據(jù)各種PLC內(nèi)部CPU的資源有關(guān)，同時(shí)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(shí)和計(jì)數(shù)的

78、時(shí)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(shí)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(gè)小小的例子來(lái)說(shuō)明.</p><p>　　每一個(gè)設(shè)備總是不會(huì)忘記有一個(gè)按鈕，它也是在我們遇到緊急情況時(shí)使用的，那就是急停按鈕。當(dāng)我們遇到人身事故和意外情況時(shí)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

79、CPU一個(gè)外部觸發(fā)信號(hào)時(shí)，CPU對(duì)I/O進(jìn)行再次檢測(cè)，當(dāng)確認(rèn)有外部觸發(fā)信號(hào)時(shí)，CPU保護(hù)現(xiàn)場(chǎng)并將程序計(jì)數(shù)器自動(dòng)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(jì)數(shù)器返回到主程序繼續(xù)工作。有一點(diǎn)可以說(shuō)明的是我們一般會(huì)把急停按鈕的外部中斷升至最高級(jí)別，從而保證安全。</p><p>　　當(dāng)我們?cè)诠ぷ魍暌粋€(gè)工件時(shí)，給PLC一個(gè)信號(hào)，將PLC的內(nèi)部計(jì)數(shù)器加1來(lái)計(jì)算我們一天的工作量時(shí)，一個(gè)簡(jiǎn)單的計(jì)數(shù)器能解決問(wèn)

80、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(jí)計(jì)數(shù)器的功能，當(dāng)我們?cè)诮邮芤恍└咚俚臄?shù)據(jù)時(shí)，這里所說(shuō)的高速是在在微秒級(jí)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計(jì)算的高速信號(hào)等，我們就要采用到高級(jí)計(jì)數(shù)器來(lái)幫助我們進(jìn)行計(jì)數(shù)。它在PLC執(zhí)行程序時(shí)一旦發(fā)現(xiàn)高級(jí)計(jì)數(shù)器對(duì)應(yīng)的中斷，就會(huì)立即放下手上的工作。經(jīng)過(guò)再次編程的梯形圖程序說(shuō)明我們?cè)趫?zhí)行

81、程序時(shí)高級(jí)計(jì)數(shù)器會(huì)自動(dòng)的執(zhí)行對(duì)應(yīng)的工作，從而將高級(jí)計(jì)數(shù)器的級(jí)別升至高一級(jí)別。</p><p>　　你也許聽(tīng)過(guò)太多的這個(gè)詞:“死機(jī)”，大致的意思是CPU工作量過(guò)大，內(nèi)部資源不足等情況造成程序無(wú)法運(yùn)行。PLC也有類似的情況，在PLC內(nèi)部有一個(gè)看門狗WDT，我們可以設(shè)置WDT一個(gè)程序運(yùn)行的時(shí)間，當(dāng)程序運(yùn)行過(guò)程中出現(xiàn)程序跳轉(zhuǎn)錯(cuò)誤時(shí)或者程序繁忙時(shí)，程序的運(yùn)行時(shí)間超過(guò)WDT的設(shè)置時(shí)間，CPU轉(zhuǎn)而WDT復(fù)位狀態(tài)。程序重新開(kāi)始運(yùn)

82、行，但對(duì)中斷不會(huì)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(shí)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(lái)，通過(guò)更直觀的動(dòng)畫圖片來(lái)進(jìn)行控制，并可以通過(guò)互聯(lián)網(wǎng)在異地進(jìn)行控制，像神舟五號(hào)的發(fā)射就是采用這種辦法來(lái)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(lái)取得。PLC的出現(xiàn)已經(jīng)足足影響了幾代人，我們