工控自動化技術文摘：接近開關有哪些種類？

這zhe種zhong開kai關guan有you時shi也ye叫jiao電dian感gan式shi接jie近jin開kai關guan。它ta是shi利li用yong導dao電dian物wu體ti在zai接jie近jin這zhe個ge能neng產chan生sheng電dian磁ci場chang接jie近jin開kai關guan時shi，使shi物wu體ti內nei部bu產chan生sheng渦wo流liu。這zhe個ge渦wo流liu反fan作zuo用yong到dao接jie近jin開kai關guan，使shi開kai關guan內nei部bu電dian路lu參can數shu發fa生sheng變bian化hua，由you此ci識shi別bie出chu有you無wu導dao電dian物wu體ti移yi近jin，進jin而er控kong製zhi開kai關guan的de通tong或huo斷duan。這zhe種zhong接jie近jin開kai關guan所suo能neng檢jian測ce的de物wu體ti必bi須xu是shi導dao電dian體ti。

這(zhe)種(zhong)開(kai)關(guan)的(de)測(ce)量(liang)通(tong)常(chang)是(shi)構(gou)成(cheng)電(dian)容(rong)器(qi)的(de)一(yi)個(ge)極(ji)板(ban)，而(er)另(ling)一(yi)個(ge)極(ji)板(ban)是(shi)開(kai)關(guan)的(de)外(wai)殼(ke)。這(zhe)個(ge)外(wai)殼(ke)在(zai)測(ce)量(liang)過(guo)程(cheng)中(zhong)通(tong)常(chang)是(shi)接(jie)地(di)或(huo)與(yu)設(she)備(bei)的(de)機(ji)殼(ke)相(xiang)連(lian)接(jie)。當(dang)有(you)物(wu)體(ti)移(yi)向(xiang)接(jie)近(jin)開(kai)關(guan)時(shi)，不(bu)論(lun)它(ta)是(shi)否(fou)為(wei)導(dao)體(ti)，由(you)於(yu)它(ta)的(de)接(jie)近(jin)，總(zong)要(yao)使(shi)電(dian)容(rong)的(de)介(jie)電(dian)常(chang)數(shu)發(fa)生(sheng)變(bian)化(hua)，從(cong)而(er)使(shi)電(dian)容(rong)量(liang)發(fa)生(sheng)變(bian)化(hua)，使(shi)得(de)和(he)測(ce)量(liang)頭(tou)相(xiang)連(lian)的(de)電(dian)路(lu)狀(zhuang)態(tai)也(ye)隨(sui)之(zhi)發(fa)生(sheng)變(bian)化(hua)，由(you)此(ci)便(bian)可(ke)控(kong)製(zhi)開(kai)關(guan)的(de)接(jie)通(tong)或(huo)斷(duan)開(kai)。這(zhe)種(zhong)接(jie)近(jin)開(kai)關(guan)檢(jian)測(ce)的(de)對(dui)象(xiang)，不(bu)限(xian)於(yu)導(dao)體(ti)，可(ke)以(yi)絕(jue)緣(yuan)的(de)液(ye)體(ti)或(huo)粉(fen)狀(zhuang)物(wu)等(deng)。

霍huo爾er元yuan件jian是shi一yi種zhong磁ci敏min元yuan件jian。利li用yong霍huo爾er元yuan件jian做zuo成cheng的de開kai關guan，叫jiao做zuo霍huo爾er開kai關guan。當dang磁ci性xing物wu件jian移yi近jin霍huo爾er開kai關guan時shi，開kai關guan檢jian測ce麵mian上shang的de霍huo爾er元yuan件jian因yin產chan生sheng霍huo爾er效xiao應ying而er使shi開kai關guan內nei部bu電dian路lu狀zhuang態tai發fa生sheng變bian化hua，由you此ci識shi別bie附fu近jin有you磁ci性xing物wu體ti存cun在zai，進jin而er控kong製zhi開kai關guan的de通tong或huo斷duan。這zhe種zhong接jie近jin開kai關guan的de檢jian測ce對dui象xiang必bi須xu是shi磁ci性xing物wu體ti。

yongnengganzhiwendubianhuadeyuanjianzuochengdekaiguanjiaoreshidianshijiejinkaiguan。zhezhongkaiguanshijiangreshidianqijiananzhuangzaikaiguandejiancemianshang，dangyouyuhuanjingwendubutongdewutijiejinshi，reshidianqijiandeshuchubianbianhua，youcibiankejiancechuyouwutijiejin。

dangguanchazhehuoxitongduiboyuandejulifashenggaibianshi，jiejindaodebodepinlvhuifashengpianyi，zhezhongxianxiangchengweiduopulexiaoying。shengnaheleidajiushiliyongzhegexiaoyingdeyuanlizhichengde。liyongduopulexiaoyingkezhichengchaoshengbojiejinkaiguan、微波接近開關等。當有物體移近時，接近開關接收到的反射信號會產生多普勒頻移，由此可以識別出有無物體接近。