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1、<p><b>  附錄</b></p><p>  Abstract: Programmable controller in the field of industrial control applications, and PLC in the application process, to ensure normal operation should be noted tha

2、t a series of questions, and give some reasonable suggestions.</p><p>  Key words: PLC Industrial Control Interference  Wiring Ground Proposal Description   Over the years, programmable logic contr

3、oller (hereinafter referred to as PLC) from its production to the present, to achieve a connection to the storage logical leap of logic; its function from weak to strong, to achieve a logic control to digital control of

4、progress; its applications from small to large, simple controls to achieve a single device to qualified motion control, process control and distribute</p><p>  Currently, PLC has been widely used in domestic

5、 and foreign steel, petroleum, chemical, power, building materials, machinery manufacturing, automobile, textile, transportation, environmental and cultural entertainment and other industries, the use of mainly divided i

6、nto the following categories:  1. Binary logic control Replace traditional relay circuit, logic control, sequential control, can be used to control a single device can also be used for multi-cluster control and automat

7、ion lines. Su</p><p>  ● AC output line and DC output lines do not use the same cable, the output line should be far from power lines and power lines, to avoid parallel.  (2)I / O wiring terminal   In

8、put Connection   ● Input wiring generally not too long. But if the environment interfere with small, small voltage drop, the input terminal can be properly longer.   ●Input / output lines can not be used with a ca

9、ble, input / output lines should be separated.  ● The extent possible, normally open contact form to conn</p><p>  ●As the PLC's output devices are packaged in printed circuit board and connected t

10、o the terminal board that if the load short-circuit connecting the output components, printed circuit boards will be burned.   ● With relay output, inductive load borne by the size, will affect the relay service li

11、fe, hence the use of inductive load shall exercise reasonable choice, or additions isolation relays.   ●PLC may interfere with the output load, so to take measures to control, such as the DC output of t</p><p

12、> ?、?PLC applications need to pay attention to the problems   PLC is an automation controls for industrial equipment, generally do not need to take measures, it can be directly used in industrial environments. Howeve

13、r, despite the high reliability as mentioned above, strong anti-interference ability, but when the production environment is too harsh, especially strong electromagnetic interference, or installed incorrectly, it may cau

14、se error or operator error, resulting in incorrect input and of th</p><p>  (1)Temperature   PLC required temperature at 0 ~ 55oC, installation, heating large components can not be placed below the space ar

15、ound the ventilation and cooling should be large enough.   (2)Humidity   To ensure the PLC, insulation, air relative humidity should be less than 85% (no condensation).   (3)Shock   PLC should be made from a strong v

16、ibration source, to prevent the vibration frequency is 10 ~ 55Hz frequent or continuous vibrations. When the environment is inevitable when using vib</p><p>  (1)The source of interference and general classi

17、fication </p><p>  PLC control system affect the source of interference, most of current or voltage produced dramatic changes in the location, the reason is the current change in magnetic field, produces ele

18、ctromagnetic radiation on equipment; magnetic field change generated currents, electromagnetic waves generated high speed. Usually different modes of electromagnetic interference by interference, into common mode and dif

19、ferential mode noise interference. </p><p>  Common mode interference is the signal-to-ground potential difference, mainly by the network in series, to potential difference and the space of electrom

20、agnetic radiation in the common signal line sensor state (in the same direction) voltage superimposed formed. Common-mode voltage circuit can be converted by asymmetric differential mode voltage, direct impact on measure

21、ment and control signals, resulting in component damage (this is the number of system I / O module, the main reason for the hig</p><p>  摘要:介紹可編程控制器在工業(yè)控制領(lǐng)域的應(yīng)用以及PLC在應(yīng)用過程中,要保證正常運(yùn)行應(yīng)該注意的一系列問題,并給出一些合理的建議。 &l

22、t;/p><p>  關(guān)鍵詞:PLC 工業(yè)控制 抗干擾 布線 接地 建議</p><p><b>  一、簡(jiǎn)述</b></p><p>  多年來,可編程控制器(以下簡(jiǎn)稱PLC)從其產(chǎn)生到現(xiàn)在,實(shí)現(xiàn)了接線邏輯到存儲(chǔ)邏輯的飛躍;其功能從弱到強(qiáng),實(shí)現(xiàn)了邏輯控制到數(shù)字控制的進(jìn)步;其應(yīng)用領(lǐng)域從小到大,實(shí)現(xiàn)了

23、單體設(shè)備簡(jiǎn)單控制到勝任運(yùn)動(dòng)控制、過程控制及集散控制等各種任務(wù)的跨越。今天的PLC在處理模擬量、數(shù)字運(yùn)算、人機(jī)接口和網(wǎng)絡(luò)的各方面能力都已大幅提高,成為工業(yè)控制領(lǐng)域的主流控制設(shè)備,在各行各業(yè)發(fā)揮著越來越大的作用。</p><p>  二、PLC的應(yīng)用領(lǐng)域</p><p>  目前,PLC在國(guó)內(nèi)外已廣泛應(yīng)用于鋼鐵、石油、化工、電力、建材、機(jī)械制造、汽車、輕紡、交通運(yùn)輸、環(huán)保及文化娛樂等各個(gè)行業(yè),

24、使用情況主要分為如下幾類:</p><p><b>  1.開關(guān)量邏輯控制</b></p><p>  取代傳統(tǒng)的繼電器電路,實(shí)現(xiàn)邏輯控制、順序控制,既可用于單臺(tái)設(shè)備的控制,也可用于多機(jī)群控及自動(dòng)化流水線。如注塑機(jī)、印刷機(jī)、訂書機(jī)械、組合機(jī)床、磨床、包裝生產(chǎn)線、電鍍流水線等。</p><p><b>  2.工業(yè)過程控制</b&

25、gt;</p><p>  在工業(yè)生產(chǎn)過程當(dāng)中,存在一些如溫度、壓力、流量、液位和速度等連續(xù)變化的量(即模擬量),PLC采用相應(yīng)的A/D和D/A轉(zhuǎn)換模塊及各種各樣的控制算法程序來處理模擬量,完成閉環(huán)控制。PID調(diào)節(jié)是一般閉環(huán)控制系統(tǒng)中用得較多的一種調(diào)節(jié)方法。過程控制在冶金、化工、熱處理、鍋爐控制等場(chǎng)合有非常廣泛的應(yīng)用。</p><p><b>  3.運(yùn)動(dòng)控制</b>

26、</p><p>  PLC可以用于圓周運(yùn)動(dòng)或直線運(yùn)動(dòng)的控制。一般使用專用的運(yùn)動(dòng)控制模塊,如可驅(qū)動(dòng)步進(jìn)電機(jī)或伺服電機(jī)的單軸或多軸位置控制模塊,廣泛用于各種機(jī)械、機(jī)床、機(jī)器人、電梯等場(chǎng)合。</p><p><b>  4.數(shù)據(jù)處理</b></p><p>  PLC具有數(shù)學(xué)運(yùn)算(含矩陣運(yùn)算、函數(shù)運(yùn)算、邏輯運(yùn)算)、數(shù)據(jù)傳送、數(shù)據(jù)轉(zhuǎn)換、排序、查表、位

27、操作等功能,可以完成數(shù)據(jù)的采集、分析及處理。數(shù)據(jù)處理一般用于如造紙、冶金、食品工業(yè)中的一些大型控制系統(tǒng)。   5.通信及聯(lián)網(wǎng)   PLC通信含PLC間的通信及PLC與其它智能設(shè)備間的通信。隨著工廠自動(dòng)化網(wǎng)絡(luò)的發(fā)展,現(xiàn)在的PLC都具有通信接口,通信非常方便。   三、PLC的應(yīng)用特點(diǎn)   1.可靠性高,抗干擾能力強(qiáng)   高可靠性是電氣控制設(shè)備的關(guān)鍵性能。PLC由于采用現(xiàn)代大規(guī)模集成電路技術(shù),采用嚴(yán)格的生產(chǎn)工藝制造,內(nèi)部電路采取了

28、先進(jìn)的抗干擾技術(shù),具有很高的可靠性。使用PLC構(gòu)成控制系統(tǒng),和同等規(guī)模的繼電接觸器系統(tǒng)相比,電氣接線及開關(guān)接點(diǎn)已減少到數(shù)百甚至數(shù)千分之一,故障也就大大降低。此外,PLC帶有硬件故障自我檢測(cè)功能,出現(xiàn)故障時(shí)可及時(shí)發(fā)出警報(bào)信息。在應(yīng)用軟件中,應(yīng)用者還可以編入外圍器件的故障自診斷程序,使系統(tǒng)中除PLC以外的電路及設(shè)備也獲得故障自診斷保護(hù)。這樣,整個(gè)系統(tǒng)將極高的可靠性。   2.配套齊全,功能完善,適用性強(qiáng)   PLC發(fā)展到今天,已經(jīng)形成了

29、各種規(guī)模的系列化產(chǎn)品,可以用于各</p><p> ?。?)溫度   PLC要求環(huán)境溫度在0~55oC,安裝時(shí)不能放在發(fā)熱量大的元件下面,四周通風(fēng)散熱的空間應(yīng)足夠大。  ?。?)濕度   為了保證PLC的絕緣性能,空氣的相對(duì)濕度應(yīng)小于85%(無凝露)。  ?。?)震動(dòng)   應(yīng)使PLC遠(yuǎn)離強(qiáng)烈的震動(dòng)源,防止振動(dòng)頻率為10~55Hz的頻繁或連續(xù)振動(dòng)。當(dāng)使用環(huán)境不可避免震動(dòng)時(shí),必須采取減震措施,如采用減震膠等

30、。 [NextPage] (4)空氣   避免有腐蝕和易燃的氣體,例如氯化氫、硫化氫等。對(duì)于空氣中有較多粉塵或腐蝕性氣體的環(huán)境,可將PLC安裝在封閉性較好的控制室或控制柜中。  ?。?)電源   PLC對(duì)于電源線帶來的干擾具有一定的抵制能力。在可靠性要求很高或電源干擾特別嚴(yán)重的環(huán)境中,可以安裝一臺(tái)帶屏蔽層的隔離變壓器,以減少設(shè)備與地之間的干擾。一般PLC都有直流24V輸出提供給輸入端,當(dāng)輸入端使用外接直流電源時(shí),應(yīng)選用直流穩(wěn)

31、壓電源。因?yàn)槠胀ǖ恼鳛V波電源,由于紋波的影響,容易使PLC接收到錯(cuò)誤信息。   2.控制系統(tǒng)中干擾及其來源   現(xiàn)場(chǎng)電磁干擾是PLC控制系統(tǒng)中最常見也是最易影響系統(tǒng)可靠性的因素之一,所謂治標(biāo)先</p><p> ?。?)干擾源及一般分類   影響PLC控制系統(tǒng)的干擾源,大都產(chǎn)生在電流或電壓劇烈變化的部位,其原因是電流改變產(chǎn)生磁場(chǎng),對(duì)設(shè)備產(chǎn)生電磁輻射;磁場(chǎng)改變產(chǎn)生電流,電磁高速產(chǎn)生電磁波。通常電磁干擾按干擾

32、模式不同,分為共模干擾和差模干擾。共模干擾是信號(hào)對(duì)地的電位差,主要由電網(wǎng)串入、地電位差及空間電磁輻射在信號(hào)線上感應(yīng)的共態(tài)(同方向)電壓疊加所形成。共模電壓通過不對(duì)稱電路可轉(zhuǎn)換成差模電壓,直接影響測(cè)控信號(hào),造成元器件損壞(這就是一些系統(tǒng)I/O模件損壞率較高的主要原因),這種共模干擾可為直流,亦可為交流。差模干擾是指作用于信號(hào)兩極間的干擾電壓,主要由空間電磁場(chǎng)在信號(hào)間耦合感應(yīng)及由不平衡電路轉(zhuǎn)換共模干擾所形成的電壓,這種干擾疊加在信號(hào)上,直接

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