【正文】 該電源一般不用于啟動(dòng)外部輸入或輸出。這將加快由于損壞零件而引起的任何問(wèn)題的修理速度。一旦系統(tǒng)修改結(jié)束，將正確的程序重新讀入PLC 控制器也是非常重要的。一個(gè)輸入的實(shí)際狀態(tài)存儲(chǔ)狀態(tài)存儲(chǔ)在專(zhuān)用存儲(chǔ)器位上，為“ 1”或者“ 0”。 PLC 使用系統(tǒng)存儲(chǔ)器（現(xiàn)在大部分采用閃存技術(shù)了）用于過(guò)程控制系統(tǒng)。 中央處理單元（ CPU）是 PLC 控制器的大腦。 第一個(gè) PLC 控制器是簡(jiǎn)單的設(shè)備。如果你正在進(jìn)行機(jī)械制造，產(chǎn)品包裝，材料處理，自動(dòng)化裝配及無(wú)數(shù)其他工業(yè)生產(chǎn)，你可能已經(jīng)用到了PLC。在有些 PLC 控制器上，你可以看見(jiàn)作為獨(dú)立模塊的電源。程序員可以添加標(biāo)記，書(shū)日和輸出設(shè)備名稱(chēng)，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。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(guò)計(jì)算機(jī)進(jìn)行編程。在應(yīng)用程序開(kāi)發(fā)中，通過(guò)一個(gè)串行電纜可以對(duì)程序存儲(chǔ)器進(jìn)行重新編程。運(yùn)算器用于進(jìn)行數(shù)字或邏輯運(yùn)算，在控制器指揮下工作。它加工溫度、 壓力、 當(dāng)前容量的不同，系統(tǒng)與 DCS 系統(tǒng)參數(shù)等使用掃描周期的快速游，一般為 ~ ，更快地選擇 50ms 年或較小掃描周期。分點(diǎn)，依法可分為： 微型 PLC： 32 I/O 小型 PLC： 256 I/O 中小型 PLC： 1,024 I/O 無(wú) 錫 職 業(yè) 技 術(shù) 學(xué) 院 畢業(yè)設(shè)計(jì)說(shuō)明書(shū)（英文翻譯） 7 大型 PLC： 4,096 I/O 巨人 PLC： 8,195 I/O 近年來(lái)已支持 300 回程路線(xiàn)的單一平面及以上 65,000 I/O 大型系統(tǒng)函授中小型 PLC、 使用 16 ~ 32 位 CPU、 微、 小型 PLC 最初使用 8 CPU，現(xiàn)在可以根據(jù)等等方面的通信要求，有些還改為 16 ~ 32 位 CPU。作為原則、 技術(shù)和工藝沒(méi)有最先進(jìn)的技術(shù)難度產(chǎn)品，那么長(zhǎng)時(shí)間一樣勤，是可以制造行業(yè)的窗體。隨著集成電路技術(shù)和計(jì)算機(jī)技術(shù)的發(fā)展，現(xiàn)在已經(jīng)第五代的 PLC 產(chǎn)品 。 As well as the massive switches quantity, the arteries impulse, the time, the counter, the simulation quantity reports to the police and so on the condition quantity primarily data acquisition surveillance. As a result of these controls and surveillance request, therefore PLC developed the substitution relay line and carries on the sequential control primarily product. In many years production practice, has gradually formed PLC, DCS and the IPC tripod sets up the potential, like table 1, but also has other single return route intelligence type regulators and so on to account for the certain percentage in the market. In the 8039。s, the personal puter develops, also the abbreviation is PC。 Another method is provides longdistance I/O from the station and so on. These all explained the PLC factory the hardware various parts to the user development, is advantageous for the user to select, disposes scale different PLC, moreover this kind of hardware disposes openness, for the manufacturer, retails business (business agent), system integration business, the enduser brings very many convenient es for the marketing supply to be very greatly convenient, this is a big success experience. In PLC I/O template, except general DI/DO, outside AD/DA template, but also has developed a series of special functions I/O template, this was PLC uses in all the various trades and occupations to open the outlet, like used in the bar code recognition ASCII/BASIC template, used in the reaction control PID template, used in the operating control, the 無(wú) 錫 職 業(yè) 技 術(shù) 學(xué) 院 畢業(yè)設(shè)計(jì)說(shuō)明書(shū)（英文翻譯） 3 machinefinishing highspeed counting template, the single axle position control template, the two axle position control template, the cam locator template, the radio frequency recognition connection template and so on, this also will be able to have the very big development in later. Moreover in the input, the output related part, the situation input, the output electricity isolation, aspect and so on isolation also can be more perfect. In PLC CPU and the memory coordination, pletes the control function. It with DCS system parameter and so on processing temperature, pressure, current capacity system different, uses the fast tour scanning cycle, generally is ~, is quicker selects 50ms or the smaller scanning cycle. It is a digital sampling control system. Central Processing Unit (CPU) is the brain of a PLC controller. CPU itself is usually one of the microcontrollers. Aforetime these were 8bit , and now these are 16and 32bitmicrocontrollers. Unspoken rule is that you’ll find mostly Hitachi and Fuji microcontrollers in PLC controllers by Japanese makers, Siemens in European controllers, and Motorola microcontrollers in American ones. CPU also takes care of munication, interconnectedness among other parts of PLC controllers, program execution, memory operation, overseeing input and setting up of an output. PLC controllers have plex routines for memory checkup in order to ensure that PLC memory was not damaged (memory checkup is done for safety reasons).Generally speaking, CPU unit makes a great number of checkups of the PLC controller itself so eventual errors would be discovered early. You can simply look at any PLC controller and see that there are several indicators in 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 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 store