【正文】 the form. of light diodes for error signalization. System memory (today mostly implemented in FLASH technology) is used by a PLC for a process control system. Aside form. This operating system it also contains a user program translated forma ladder diagram to a binary form. FLASH memory contents can be changed only in case where user program is being changed. PLC controllers were used earlier instead of 無 錫 職 業(yè) 技 術(shù) 學(xué) 院 畢業(yè)設(shè)計(jì)說明書（英文翻譯） 5 PLASH memory and have had EPROM memory instead of FLASH memory which had to be erased with UV lamp and programmed on programmers. With the use of FLASH technology this process was greatly shortened. Reprogramming a program memory is done through a serial cable in a program for application development. User memory is divided into blocks having special functions. Some parts of a memory are used for storing input and output status. The real status of an input is stored either as “1”or as “0”in a specific memory bit/ each input or output has one corresponding bit in memory. Other parts of memory are used to store variable contents for variables used in used program. For example, time value, or counter value would be stored in this part of the memory. PLC controller can be reprogrammed through a puter (usual way), but also through manual programmers (consoles). This practically means that each PLC controller can programmed through a puter if you have the software needed for programming. Today’s transmission puters are ideal for reprogramming a PLC controller in factory itself. This is of great importance to industry. Once the system is corrected, it is also important to read the right program into a PLC again. It is also good to check from time to time whether program in a PLC has not changed. This helps to avoid hazardous situations in factory rooms (some automakers have established munication works which regularly check programs in PLC controllers to ensure execution only of good programs). Almost every program for programming a PLC controller possesses various useful options such as: forced switching on and off of the system input/outputs (I/O lines), program follow up in real time as well as documenting a diagram. This documenting is necessary to understand and define failures and malfunctions. Programmer can add remarks, names of input or output devices, and ments that can be useful when finding errors, or with system maintenance. Adding ments and remarks enables any technician (and not just a person who developed the system) to understand a ladder diagram right away. Comments and remarks can even quote precisely part numbers if replacements would be needed. This would speed up a repair of any problems that e up due to bad parts. The old way was such that a person who developed a system had protection on the program, so nobody aside from this person could understand how it was done. Correctly documented ladder diagram allows any technician to understand thoroughly how system functions. Electrical supply is used in bringing electrical energy to central processing unit. Most PLC controllers work either at 24 VDC or 220 VAC. On some PLC controllers you’ll find electrical supply as a separate module. Those are usually bigger PLC controllers, while small and medium series already contain the supply module. User has to determine how much current to take from I/O module to ensure that electrical supply provides appropriate amount of current. Different types of modules use different amounts of electrical current. This electrical supply is usually not used to start external input or output. User has to provide separate supplies in starting PLC controller inputs because then you can ensure so called “pure” supply for the PLC controller. With pure supply we mean supply where industrial environment can not affect it damagingly. Some of the smaller PLC controllers supply their inputs with voltage from a small supply source already incorporated into a PLC. 中文 PLC 發(fā)展和市場條件 PLC 發(fā)展歷史 可編程邏輯控制器的英文名字是可編程序控制器，在 20 世紀(jì) 7080 年齡不斷的縮寫是 PC。 PLC 機(jī)的結(jié)果關(guān)系處理模擬能力和網(wǎng)絡(luò)方面的功能研究進(jìn)展中，已 經(jīng)占領(lǐng)市場的一部分 DCS (過程控制 ) 和已逐漸壟斷行業(yè)污水處理，但的工業(yè) PC (IPC) 外觀，特別是近年來在現(xiàn)場總線技術(shù)的發(fā)展， IPC 和功能界別亦已占領(lǐng) PLC 市場的一部分，因此近年來 PLC 率的上升，總是說是逐步緩慢。 看了從技術(shù)創(chuàng)新角度，我國大中型企業(yè)還必須大力發(fā)展 CIMS (計(jì)算機(jī)集成制造系統(tǒng) )、 形式的 FMS 靈活性必須制造系統(tǒng)機(jī)械工廠， PLC 是一個(gè)基礎(chǔ)，所以 PLC 市場是廣泛。 在 PLC I/O 模板中，除了一般的迪 / 廣告 /DA 模板，外面做但還制定了一系列的特殊功能 I/O 模板，這是所有各個(gè)行業(yè)的職業(yè)，像打開電源插座， PLC 用途在反應(yīng)的 PID 控制模板，用于運(yùn)行控制所使用的條碼識(shí)別 ASCII/基本模板中使用機(jī)械加工高速計(jì)數(shù)模板， 單軸位置控制模板中，兩個(gè)軸定位控件模板、 凸輪定位器模板、 無線電頻率識(shí)別連接模板等，這也將是能夠以后有很大的發(fā)展。 在使用者看來，不必要詳細(xì)分析 CPU 的內(nèi)部電路，但對(duì)各部分的工作機(jī)制還是應(yīng)有足夠的理解。快擦型存儲(chǔ)器（ FLASH memory）的內(nèi)容只有在改變用戶程序的時(shí)候可以被改變。另外一部分存儲(chǔ)器用來存儲(chǔ)用戶程序中的變 量的內(nèi)容。這有助于避免車間發(fā)生危險(xiǎn)情況（一些汽車制造商已經(jīng)建立了通信網(wǎng)絡(luò)，可 以定期檢查 PLC 中的程序，以保證運(yùn)行的程序都是正確的）。正確的、備有證明文件的梯形圖使任何技術(shù)人員都能徹底理解系統(tǒng)的功能。使用 純電源意味著工業(yè)環(huán)境中的電源不會(huì)嚴(yán)重影響它。如圖所示。工作速度和編程的簡易性也都得到改善。為了保證 PLC 存儲(chǔ)器不被損壞， PLC 控制器檢查存儲(chǔ)器的程 序很復(fù)雜（由于安無 錫 職 業(yè) 技 術(shù) 學(xué) 院 畢業(yè)設(shè)計(jì)說明書（英文翻譯） 9 全原因進(jìn)行存儲(chǔ)器檢查）。在應(yīng)用程序開發(fā)中，通過一個(gè)串行電纜可以對(duì)程序存儲(chǔ)器進(jìn)行重新編程。實(shí)際上，這意味著，如果你有編程所需要的軟件，早期 PLC 控制器可以通過計(jì)算機(jī)進(jìn)行編程。程序員可以添加標(biāo)記，書日和輸出設(shè)備名稱，以及對(duì)于查找錯(cuò)誤或者對(duì)于系統(tǒng)維護(hù)很有用的注釋。在有些 PLC 控制器上，你可以看見作為獨(dú)立模塊的電源。有些較小的 PLC 控制器從與 PLC 控制器集成在一起的小電源為它們 的輸入提供電壓源。 電源是為中央處理單元提供電源的。 幾乎所有用于為 PLC 控制器編程的程序都 擁有各種不同的選項(xiàng)，例如系統(tǒng)輸入 /輸出（ I/O 線）的強(qiáng)制開關(guān)，程序?qū)崟r(shí)跟蹤以及圖表驗(yàn)證。例如，定時(shí)器值，或者記數(shù)器值存放在存儲(chǔ)器的這個(gè)部分。 PLC 控制器比快擦型存儲(chǔ)器使用得更早， EPROM 存儲(chǔ)器比快擦型存儲(chǔ)器也更早，快擦型存儲(chǔ)器必須 用紫外線（ UV， UltraViolet Ray）燈擦除，并在編程器上進(jìn)行編程。不言而喻的原則是，你將在日本生產(chǎn)商制造的 PLC 控