【正文】 例如，使用模糊控制將有效地解決料筒溫度控制中強(qiáng)禍合、大慣量等問題。 中間繼電器選擇中間繼電器時(shí)，首先要注意的線圈電流的種類（是交流還是直流），其線圈的電壓或電流應(yīng)滿足電路的要求。通常高速液壓馬達(dá)輸出轉(zhuǎn)矩不大所以又稱為高速小轉(zhuǎn)矩液壓馬達(dá)。熱電偶測(cè)溫的基本原理是熱電效應(yīng)。
當(dāng)信號(hào)轉(zhuǎn)移到S21（即STL S21）時(shí)，需要處理的相關(guān)信號(hào)有：確定合模安全時(shí)（安全光柵X12）為“0”，合模Y2并自鎖；復(fù)位開關(guān)X2為“0”，合模到位接近開關(guān)為“1” ，信號(hào)轉(zhuǎn)移到S22；當(dāng)復(fù)位開關(guān)X2為“1”，信號(hào)轉(zhuǎn)移到S26。預(yù)塑完后接近開關(guān)工作，整進(jìn)電磁閥斷電自復(fù)位，射臺(tái)在液壓的作用下退回。
選擇時(shí)應(yīng)考慮負(fù)載電壓的種類和大小、系統(tǒng)對(duì)延遲時(shí)間的要求、負(fù)載狀態(tài)變化是否頻繁等，還應(yīng)注意同一輸出模塊對(duì)電阻性負(fù)載、電感性負(fù)載和白熾燈的驅(qū)動(dòng)能力的差異。 I/O模塊的選擇PLC是一種工業(yè)控制系統(tǒng)，他的控制對(duì)象是工業(yè)生產(chǎn)設(shè)備或工業(yè)生產(chǎn)過程他的工作環(huán)境是工業(yè)生產(chǎn)現(xiàn)場(chǎng)。
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PLC的特點(diǎn)之一是使用靈活。 保模時(shí)間高溫原材料擠入模具后，需要在模具中冷卻一段時(shí)間，讓其基本成型后才能打開模具，這一段時(shí)間為保模時(shí)間。 合模部分它是保證成型模具可靠地閉合和實(shí)現(xiàn)模具啟閉動(dòng)作，并頂出制品，即成型制品的工作部件。綜上所述，開展基于PLC的注塑機(jī)的控制研究，是一個(gè)有理論意義，又有很高應(yīng)用價(jià)值的研究課題。通過組態(tài)軟件的仿真配合，設(shè)計(jì)出一個(gè)完整的由PLC控制的注塑機(jī)系統(tǒng)，實(shí)現(xiàn)低能耗、低噪音、鎖模力容易控制、運(yùn)行平穩(wěn)、安全可靠和便于維修的目標(biāo)。近年來，中小型注塑機(jī)的技術(shù)發(fā)展非常迅速，就工藝參數(shù)而言，塑化能力、注射壓力等都有很大提高。目前世界上80%的工程塑料制品采用注射成型加工技術(shù)進(jìn)行生產(chǎn)。 本課題的主要內(nèi)容注塑機(jī)是一種能一次成型外型復(fù)雜、尺寸精確或帶有金屬嵌件的質(zhì)地密致的塑料制品的塑料生產(chǎn)設(shè)備，它是將粒狀或粉狀塑料加入機(jī)筒內(nèi)，并通過螺桿的旋轉(zhuǎn)和機(jī)筒外壁加熱使塑料成為熔融狀態(tài)，然后機(jī)器進(jìn)行合模和注射座前移，使噴嘴貼緊模具的澆口道，接著向注射缸通人壓力油，使螺桿向前推進(jìn)，從而以很高的壓力和較快的速度將熔料注入溫度較低的閉合模具內(nèi)，經(jīng)過一定時(shí)間和壓力保持（又稱保壓）、冷卻，使其固化成型，便可開模取出制品，從而得到所需的成品。
注塑機(jī)一般分為手動(dòng)、自動(dòng)兩種工作模式。對(duì)于控制比較復(fù)雜、控制要求比較高的工程項(xiàng)目，如要實(shí)現(xiàn)PID運(yùn)算、閉環(huán)控制、通信聯(lián)網(wǎng)等，可根據(jù)控制規(guī)模及復(fù)雜程度的程度，選用中檔機(jī)或高檔機(jī)。對(duì)于開關(guān)量控制系統(tǒng)，存儲(chǔ)器字?jǐn)?shù)為開關(guān)量乘以8；對(duì)于有模擬量控制功能的PLC，所需存儲(chǔ)器字?jǐn)?shù)為模擬內(nèi)存單元數(shù)乘以100。典型的交流I/O信號(hào)為24～240V（AC），直流I/O信號(hào)為0～10V（DC）。 本系統(tǒng)中實(shí)際需要輸入點(diǎn)17點(diǎn)，輸出點(diǎn)8點(diǎn)，根據(jù)輸入輸出點(diǎn)數(shù)，以及考慮到今后對(duì)系統(tǒng)的維護(hù)和擴(kuò)充使用，要保留一定的裕量，因此我們選用的PLC型號(hào)為三菱公司的FX2N系列，其選擇如下：
基本單元：FX2N48MR（輸入點(diǎn)24點(diǎn)，輸出點(diǎn)24點(diǎn)）
功能模塊：FX2N－4ADTC模塊1個(gè)、FX2N－4DA模塊1個(gè)、FX2N422BD通信口1個(gè) 在確定了控制對(duì)象的控制任務(wù)和選擇好PLC的機(jī)型后，即可安排輸入、輸出的配置，并對(duì)輸入、輸出進(jìn)行地址編號(hào)。故在編制PLC程序時(shí)，選用D作為T、C的間接數(shù)據(jù)寄存器，該機(jī)PLC順序控制系統(tǒng)圖，狀態(tài)轉(zhuǎn)移的描述文字如下：當(dāng)PLC通電后在初始脈沖的作用下系統(tǒng)進(jìn)入準(zhǔn)備狀態(tài)S0等待進(jìn)一步的操作
當(dāng)按下油泵電機(jī)啟動(dòng)按鈕信號(hào)轉(zhuǎn)移到S20（即STL S20）時(shí)，需要處理的相關(guān)信號(hào)有：首先油泵電機(jī)啟動(dòng)接觸器Y0得電，使油泵電機(jī)按星三角降壓啟動(dòng)的方式啟動(dòng)。溫度傳感器是最早開發(fā)，應(yīng)用最廣的一類傳感器。從能量轉(zhuǎn)換的觀點(diǎn)來看，液壓泵與液壓馬達(dá)是可逆工作的液壓元件，向任何一種液壓泵輸入工作液體，都可使其變成液壓馬達(dá)工況；反之，當(dāng)液壓馬達(dá)的主軸由外力矩驅(qū)動(dòng)旋轉(zhuǎn)時(shí)，也可變?yōu)橐簤罕霉r。因此，凡電機(jī)長期運(yùn)行時(shí)，都需要對(duì)其過載提供保護(hù)裝置。因?yàn)榭煽焖偾袛嘟涣髋c直流主回路和可頻繁地接通與大電流控制(某些型別可達(dá)800安培)電路的裝置，所以經(jīng)常運(yùn)用于電動(dòng)機(jī)作為控制對(duì)象，也可用作控制工廠設(shè)備﹑電熱器﹑工作母機(jī)和各樣電力機(jī)組等電力負(fù)載，并作為遠(yuǎn)距離控制裝置。 eightyfourth project, was the result. Bedford Associates started a new pany dedicated to developing, manufacturing, selling, and servicing this new product: Modicum, which stood for Modular Digital Controllers. One of the people who worked on that project was Dick Morley, who is considered to be the father of the PLC. The Modicum brand was sold in 1977 to Gould Electronics, and later acquired by German Company AEG and then by French Schneider Electric, the current owner. One of the very first 084 models built is now on display at Modicum’s headquarters in North Andover, Massachusetts. It was presented to Modicum by GM, 2when the unit was retired after nearly twenty years of uninterrupted service. Modicum used the 84 moniker at the end of its product range until the 984 made its appearance. The automotive industry is still one of the largest users of PLC. Development Early PLC was designed to replace relay logic systems. These PLC were programmed in ladder logic, which strongly resembles a schematic diagram of relay logic. This program notation was chosen to reduce training demands for the existing technicians. Other early PLC used a form of instruction list programming, based on a stackbased logic solver. Modern PLC can be programmed in a variety of ways, from ladder logic to more traditional programming languages such as BASIC and C. Another method is State Logic, a very highlevel programming language designed to program PLC based on state transition diagrams. Many early PLC did not have acpanying programming terminals that were capable of graphical representation of the logic, and so the logic was instead represented as a series of logic expressions in some version of Boolean format, similar to Boolean algebra. As programming terminals evolved, it became more mon for ladder logic to be used, for the aforementioned reasons. Newer formats such as State Logic and Function Block (which is similar to the way logic is depicted when using digital integrated logic circuits) exist, but they are still not as popular as ladder logic. A primary reason for this is that PLC solve the logic in a predictable and repeating sequence, and ladder logic allows the programmer (the person writing the logic) to see any issues with the timing of the logic sequence more easily than would be possible in other formats. Programming Early PLC, up to the mid1980s, were programmed using proprietary programming panels or specialpurpose programming terminals, which often had dedicated function keys representing the various logical elements of PLC programs. Programs were stored on cassette tape cartridges. Facilities for printing and documentation were very minimal due to lack of memory capacity. The very oldest PLC used nonvolatile magnetic core memory. More recently, PLC are programmed using application software on personal puters. The puter is connected to the PLC through Ethernet, RS232, RS485 or RS422 cabling. The programming software allows entry and editing of the 3ladderstyle logic. Generally the software provides functions for debugging and troubleshooting the PLC software, for example, by highlighting portions of the logic to show current status during operation or via simulation. The software will upload and download the PLC program, for backup and restoration purposes. In some models of programmable controller, the program is transferred from a personal puter to the PLC though a programming board which writes the program into a removable chip such as an EEPROM or EPROM. The functionality of the PLC has evolved over the years to include sequential relay control, motion control, process control, distributed control systems and networking. The data handling, storage, processing power and munication capabilities of some modern PLC are approximately equivalent to desktop puters. PLClike programming bined with remote I/O hardware, allow a generalpurpose desktop puter to overlap some PLC in certain applications. Regarding the practicality of these desktop puter based logic controllers, it is important to note that they have not been generally accepted in heavy industry becaus