一、光電傳感器工作原理
光(guang)(guang)(guang)(guang)電(dian)傳感器是(shi)通過把光(guang)(guang)(guang)(guang)強度的(de)(de)變化轉(zhuan)換成(cheng)(cheng)電(dian)信號(hao)的(de)(de)變化來(lai)(lai)實現控制的(de)(de)。一般情況下,它是(shi)由(you)發(fa)送器、接收(shou)器和檢測電(dian)路三部(bu)分構成(cheng)(cheng)。發(fa)送器對準目標發(fa)射(she)光(guang)(guang)(guang)(guang)束(shu)(shu),發(fa)射(she)的(de)(de)光(guang)(guang)(guang)(guang)束(shu)(shu)一般來(lai)(lai)源于(yu)半導體光(guang)(guang)(guang)(guang)源,發(fa)光(guang)(guang)(guang)(guang)二極管、激光(guang)(guang)(guang)(guang)二極管及紅(hong)外發(fa)射(she)二極管。光(guang)(guang)(guang)(guang)束(shu)(shu)不間斷地發(fa)射(she),或(huo)者改變脈沖(chong)寬度。接收(shou)器有(you)光(guang)(guang)(guang)(guang)電(dian)二極管、光(guang)(guang)(guang)(guang)電(dian)三極管、光(guang)(guang)(guang)(guang)電(dian)池組(zu)成(cheng)(cheng)。在接收(shou)器的(de)(de)前面(mian),裝有(you)光(guang)(guang)(guang)(guang)學(xue)元(yuan)件如透鏡和光(guang)(guang)(guang)(guang)圈(quan)等。在其(qi)后面(mian)是(shi)檢測電(dian)路,它能濾(lv)出有(you)效(xiao)信號(hao)和應(ying)用(yong)該信號(hao)。
二、光電傳感器有哪幾種
1、光電傳感器按外殼型狀分類:圓柱型,方型。
光電傳(chuan)感器的外殼(ke)現在是根據客戶的安裝環境(jing)而選擇圓型(xing)或方型(xing),這個沒有規定的。
2、光電傳感器按檢測方式分類:對射式、鏡反射式、漫反射式。
對射(she)式光電傳感器是光電傳感器里檢測(ce)距(ju)離最遠的,距(ju)離可達(da)幾(ji)米甚至十幾(ji)米。安裝(zhuang)必須要一個(ge)發光器和(he)接收器對著安裝(zhuang)。
鏡反射式光電傳感器的檢測距離比對射傳感器的檢(jian)測(ce)距離(li)稍(shao)微短一些,但是安(an)(an)裝(zhuang)(zhuang)卻比(bi)對射光傳感器方便很(hen)多,可(ke)以(yi)在窄小的空間安(an)(an)裝(zhuang)(zhuang),只要配合安(an)(an)裝(zhuang)(zhuang)反光鏡即可(ke),特點就是專業(ye)檢(jian)測(ce)透明物體的有無。
漫反(fan)射光(guang)電傳感器(qi)的檢測距離就不如上(shang)面兩個了,但是(shi)漫反(fan)射光(guang)電傳感器(qi)的安(an)裝方式、安(an)裝位置都比前(qian)兩個更方便。
3、光電傳感器按光源分類:可見紅光、不可見紅外光、激光。
光(guang)(guang)(guang)電傳感(gan)器的(de)光(guang)(guang)(guang)源(yuan)是(shi)根據客(ke)戶(hu)的(de)要(yao)求(qiu)和(he)檢(jian)測物(wu)體、檢(jian)測環境(jing)而(er)選擇,可見(jian)光(guang)(guang)(guang)紅光(guang)(guang)(guang)和(he)不可見(jian)紅光(guang)(guang)(guang)會(hui)隨著(zhu)距(ju)離的(de)遠近而(er)改變(bian)光(guang)(guang)(guang)斑的(de)大(da)小(xiao),但是(shi)激光(guang)(guang)(guang)卻不會(hui),激光(guang)(guang)(guang)不會(hui)因為(wei)距(ju)離而(er)改變(bian)光(guang)(guang)(guang)斑的(de)大(da)小(xiao),激光(guang)(guang)(guang)適合(he)檢(jian)測小(xiao)物(wu)體或(huo)微(wei)型物(wu)體的(de)有無,計(ji)數,定位等應用(yong)。
三、光電傳感器的實際應用
光電傳感器(qi)可以用于檢測直(zhi)接引起光量(liang)變化的(de)非(fei)電量(liang),如光強、光照度、輻射測溫、氣體(ti)成分分析(xi)等;也可用來(lai)檢測能轉換(huan)成光量(liang)變化的(de)其(qi)他非(fei)電量(liang),如零(ling)件(jian)直(zhi)徑、表面粗糙度、應變、位移、振動、速度、加速度,以及物體(ti)的(de)形狀(zhuang)、工作狀(zhuang)態的(de)識別等。
1、條形碼掃描筆
當(dang)(dang)掃描筆頭(tou)在條形碼(ma)(ma)上(shang)移(yi)動時,若遇(yu)到(dao)黑色線(xian)條,發光(guang)(guang)(guang)二極(ji)管(guan)的(de)光(guang)(guang)(guang)線(xian)將被(bei)黑線(xian)吸(xi)收,光(guang)(guang)(guang)敏(min)(min)三(san)(san)極(ji)管(guan)接收不到(dao)反射光(guang)(guang)(guang),呈高(gao)阻抗,處于截止(zhi)狀態。當(dang)(dang)遇(yu)到(dao)白色間隔時,發光(guang)(guang)(guang)二極(ji)管(guan)所發出的(de)光(guang)(guang)(guang)線(xian),被(bei)反射到(dao)光(guang)(guang)(guang)敏(min)(min)三(san)(san)極(ji)管(guan)的(de)基極(ji),光(guang)(guang)(guang)敏(min)(min)三(san)(san)極(ji)管(guan)產(chan)生光(guang)(guang)(guang)電(dian)流而導通。整(zheng)個(ge)條形碼(ma)(ma)被(bei)掃描過之(zhi)后(hou),光(guang)(guang)(guang)敏(min)(min)三(san)(san)極(ji)管(guan)將條形碼(ma)(ma)變形一個(ge)個(ge)電(dian)脈沖(chong)信號,該信號經(jing)放大、整(zheng)形后(hou)便形成(cheng)脈沖(chong)列,再經(jing)計算機處理(li),完成(cheng)對條形碼(ma)(ma)信息的(de)識別(bie)。
2、簡易感光報警器
當無光照(zhao)時(shi),硅光電(dian)(dian)(dian)(dian)(dian)(dian)池無電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)產生,此時(shi)硅光電(dian)(dian)(dian)(dian)(dian)(dian)池相當于一個電(dian)(dian)(dian)(dian)(dian)(dian)阻串接(jie)在放大(da)器的基(ji)極電(dian)(dian)(dian)(dian)(dian)(dian)路上(shang)。當有光照(zhao)時(shi),硅光電(dian)(dian)(dian)(dian)(dian)(dian)池產生電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya),該電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)與R2上(shang)的電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)一起加(jia)在VT1管的基(ji)極,于是VT1導通,VT2、VT3也隨之導通,繼電(dian)(dian)(dian)(dian)(dian)(dian)器K工作(zuo),其觸點被吸合,蜂鳴器發出報警(jing)聲響。
3、產品計數
產品(pin)在(zai)傳送帶上運行時,不(bu)斷(duan)地遮擋(dang)光(guang)(guang)(guang)源(yuan)到光(guang)(guang)(guang)敏(min)器件(jian)間的(de)光(guang)(guang)(guang)路(lu),使光(guang)(guang)(guang)電(dian)脈(mo)沖(chong)電(dian)路(lu)隨產品(pin)的(de)有(you)無產生(sheng)一個(ge)個(ge)電(dian)脈(mo)沖(chong)信號。產品(pin)每遮光(guang)(guang)(guang)一次,光(guang)(guang)(guang)電(dian)脈(mo)沖(chong)電(dian)路(lu)便(bian)產生(sheng)一個(ge)脈(mo)沖(chong)信號,因(yin)此,輸出的(de)脈(mo)沖(chong)數即代(dai)表產品(pin)的(de)數目。該脈(mo)沖(chong)經計數電(dian)路(lu)計數并由顯示電(dian)路(lu)顯示出來。
4、光電式煙霧報警器
沒(mei)有(you)煙(yan)霧(wu)時(shi),發(fa)光(guang)二(er)極(ji)管發(fa)出(chu)的光(guang)線直線傳播,光(guang)電三(san)(san)極(ji)管沒(mei)有(you)接收(shou)信號,沒(mei)有(you)輸出(chu);有(you)煙(yan)霧(wu)時(shi),發(fa)光(guang)二(er)極(ji)管發(fa)出(chu)的光(guang)線被煙(yan)霧(wu)顆粒(li)折射,使(shi)三(san)(san)極(ji)管接受到(dao)光(guang)線,有(you)信號輸出(chu),發(fa)出(chu)報警。
5、防盜報警電路
將光電斷路器安裝于抽屜(ti)的(de)(de)背(bei)后,并(bing)設一電(dian)源開關置于隱蔽的(de)(de)地方(fang),當需要(yao)防盜(dao)時,將(jiang)開關合(he)上。平時由于擋(dang)板(ban)插入槽(cao)口,光電(dian)三極僅有暗電(dian)流,BG不導(dao)通(tong),繼電(dian)器(qi)J不吸合(he)。當小偷撬開抽屜(ti)時,一拉開抽屜(ti)則擋(dang)板(ban)離(li)開槽(cao)口,光電(dian)三極管的(de)(de)光電(dian)流使R2上產(chan)生接近電(dian)源的(de)(de)電(dian)壓,BG導(dao)通(tong),繼電(dian)器(qi)吸合(he),發出(chu)報警信號。
6、公共汽車關門安全指示器
當(dang)(dang)車(che)門(men)(men)關好(hao)時(shi)(shi),擋板(ban)插入光電(dian)(dian)斷路器槽口,光電(dian)(dian)三(san)極管無工(gong)作電(dian)(dian)流,其(qi)輸出為高電(dian)(dian)平(ping)(ping);當(dang)(dang)三(san)個(ge)車(che)門(men)(men)全關好(hao)時(shi)(shi),則相應地輸出三(san)個(ge)高電(dian)(dian)平(ping)(ping)信號。則與門(men)(men)的輸出為高電(dian)(dian)平(ping)(ping),綠(lv)燈(deng)亮。若其(qi)中有一(yi)個(ge)車(che)門(men)(men)沒(mei)關好(hao)(或(huo)沒(mei)關嚴(yan)),則與門(men)(men)輸出為低電(dian)(dian)平(ping)(ping),使紅燈(deng)亮。