【正文】 復(fù)雜的生產(chǎn)需要 ； 發(fā)展價(jià)格低廉，功能簡(jiǎn)單的 專(zhuān)用 PLC 來(lái)替代繼電器 。 PLC 的特點(diǎn)、應(yīng)用領(lǐng)域和發(fā)展趨勢(shì) PLC 的主要特點(diǎn)： (1)可靠性高、抗干擾能力強(qiáng) 為保證 PLC 能在工業(yè)環(huán)境下可靠工作，在設(shè)計(jì)和生產(chǎn)過(guò)程中采取了一系列硬件和軟件的抗干擾措施。隨著當(dāng)今企業(yè)現(xiàn)代化生產(chǎn)規(guī)模不斷擴(kuò)大和深化，倉(cāng)庫(kù)成為生產(chǎn)物流系統(tǒng)中一個(gè)重要而不可或缺的環(huán)節(jié)，而立體倉(cāng)庫(kù)正以其占地面積小和空間使用率佳 的特點(diǎn) ， 正在 逐步 替代 面積利用率低且陳舊落后的平 面?zhèn)}庫(kù)，這種替代大大提高了倉(cāng)儲(chǔ)物流的水平。國(guó)際電工委員會(huì)（ IEC）在 1985 年的 PLC 標(biāo)準(zhǔn)草案第 3 稿中對(duì)它作了如下定義： “ 可編程序控制器是一種數(shù)字運(yùn)算的電子系統(tǒng)，專(zhuān)為在工業(yè)環(huán)境下應(yīng)用而設(shè)計(jì)。特別是在輕工行業(yè)中，因生產(chǎn)門(mén)類(lèi)多，加工方式多變，產(chǎn)品更新?lián)Q代快，所以 PLC 廣泛的應(yīng)用在組合機(jī)床電氣 設(shè)備中。采用皮帶、直線導(dǎo)軌、主流減速電機(jī)作為傳動(dòng)裝置，由 PLC 編程實(shí)現(xiàn) X、 Y、 Z 軸位置控制，可完成倉(cāng)庫(kù)貨物模型的自動(dòng) /手動(dòng)存取。這種電平可產(chǎn)生計(jì)數(shù)脈沖，將計(jì)數(shù)脈沖傳送給 PLC 對(duì)比，通過(guò) X、 Y 兩方向的不同的計(jì)數(shù)脈沖數(shù)來(lái)確定立體倉(cāng)庫(kù)的定位。分別編程后再進(jìn)行程序匯總。同時(shí)取貨程序和送貨程序還應(yīng)有互鎖程序，不能同時(shí)執(zhí)行以防出現(xiàn)雙線圈的現(xiàn)象。 MCGS 組態(tài)環(huán)境是生成用戶(hù)應(yīng)用系統(tǒng)的工作環(huán)境，用戶(hù)在 MCGS 組態(tài)環(huán)境中完成動(dòng)畫(huà)設(shè)計(jì)、設(shè)備連接、編寫(xiě)控制流程、編制工程打印報(bào)表等全部組態(tài)工作后，生成擴(kuò)展名為 .mcg的工程文件（又稱(chēng)為組態(tài)結(jié)果數(shù)據(jù)庫(kù)）。 河北大學(xué) 20xx屆本科生畢業(yè)論文（設(shè)計(jì)） 21 ③ .單擊繪圖工具箱中的“插入元件”按鈕 ，打開(kāi)“對(duì)象元件庫(kù)管理”窗口，單擊左側(cè)的“對(duì)象元件列表” 中相應(yīng)的文件夾，在右側(cè)的顯示框中就會(huì)顯示該文件夾包含的所有元件，選中滿(mǎn)意的元件，單擊“確定”即可將該元件加入到動(dòng)畫(huà)制作窗口，如圖 49所示。該系統(tǒng)具有接線簡(jiǎn)單、編程直觀、操作容易等特點(diǎn)。 the simplest are AC and DC inputs. Sourcing and sinking inputs are also popular. This output method dictates that a device does not supply any power. Instead, the device only switches current on or off, like a simple switch [6]. PLC inputs must convert a variety of logic levels to the 5VDC logic levels used on the data bus. This can be done with circuits similar to those shown in Figure 2. Basically the circuits condition the input to drive an optocoupler. This electrically isolates the external electrical circuitry from the internal circuitry. Other circuit ponents are used to guard against excess or reversed voltage polarity. PLC outputs must convert the 5VDC logic levels on the PLC data bus to external voltage levels. This can be done with circuits similar to those shown in Figure 3. Basically, the circuits use an optocoupler to switch external circuitry. This electrically isolates the external electrical circuitry from the internal circuitry. Other circuits ponents are used to guard against excess or reversed voltage polarity [7]. The overall design of the model is shown in Figure 4. And the schematic of this design shown in Figure 5. The full description of connection for this design is very plex and it has many details, therefore I will describe the connection of the main parts only. 河北大學(xué) 20xx屆本科生畢業(yè)論文（設(shè)計(jì)） 49 3 Hardware Design of PLC Trainer Model The hardware design of this trainer consists of three main parts: ? Main unit of PLC model and its power supply The PLC model used in this design contains two parts. The first presents the main digital PLC that contains: RS232 connecter to apply the software program to PLC, 24 digital inputs drawing on cover by I00 → I23, 16 digital outputs drawing by O00 → O15with six mon ports and 25 pins adapter to execute the additional modules of PLC. Figure 6 shows the main unit of PLC with power supply. 河北大學(xué) 20xx屆本科生畢業(yè)論文（設(shè)計(jì)） 50 The second part of this unit is a single analog PLC that contains two channels of analog inputs which are drawing by symbols (CH0(input) (I0,V0,COM0) and CH1 (input) (I1,V1, COM1)), one analog output channel (CH0(output)(V+,V–,I+,I–) and 25pins adapter to add another module (see Figure 6). Power supply for this unit is 24 VDC/5 A contain two supply ports (see Figure 6). The connection of I/O PLC with board achieved by sets of pinions and LED’s for indication (On/Off). Figure 7 presents the connection between PLC unit and in the experiments board. ? Sensor, Relay and other ponents The trainer contains two types of sensors: an approximate sensor that has 5sides detection with model TURCK Bi15cp40 APcx sn:15 mm and photoelectric sensors with two models BR100DDTP and BEN10MTFR. The first detects any interrupt within a range of 8 meters and the second detects the reflection from a certain crystal surface within a range of 8 meters. Two types of relays are used in the board: twopoles and threepoles 24VDC. Figure 8 presents the two relays, the sensors and the connection in the board. 河北大學(xué) 20xx屆本科生畢業(yè)論文（設(shè)計(jì)） 51 Many other ponents that are used in the broad to connect the experiments such as four 7segments, three digital ammeters and three digital voltmeter, three variable resistance 20 Kohm to execute the analog to digital convertor (A/D) and opposite (D/A) and power supply with two 12VDC ports, two 5VDC ports and four 24 VDC ports. Figure 9 presents the power supply ports in the board. Figure 10 presents the ammeters and converter A/D. DC motor with model GMN3MX027A DC24V and driver for AC and DC motor start/stop, direction and emergency control of DC motor and speed control AC motor are implemented in the board. Figure 11 presents the connection of the motor and drivers in the board. ? Experiments board The board is designed to implement many experiments, some of the experiments the connection diagram is plotted on the board such as traffic light control. Figure 12 presents the overall board design. 河北大學(xué) 20xx屆本科生畢業(yè)論文（設(shè)計(jì)） 52 4 Software Design of PLC Trainer Model LS industrial system pany GM7DR40 PLC uses the language announced as an international standard by IEC (International Electro technical Commission). The international standard languages such as LD, SFC, IL available to select the language are easy to apply to the system. I used the LD (Ladder Diagram) to build the program for experiments. Figure 13 presents the main window for building the program and simulating the instruction before writing on the memory of PLC through the RS232 connecter. Every instruction in the program must be piled before writing the process code to the memory of PLC. After pilation we can simulate the program to check and explain the working of real PLC with this program and the input to simulation process can be done manually, all these processes are shown in Figure 13. 5 Experiments of PLC Trainer This trainer is designed to implement the e