PT100熱電阻的接線方式？

目前熱電阻的引線主要有三種方式  
○1二線制：在熱電阻的兩端各連接一根導線來引出電阻信號的方式叫二線制：這種引線方法很簡單，但由于連接導線必然存在引線電阻r，r大小與導線的材質和長度的因素有關，因此這種引線方式只適用于測量精度較低的場合   

○2三線制：在熱電阻的根部的一端連接一根引線，另一端連接兩根引線的方式稱為三線制，這種方式通常與電橋配套使用，可以較好的消除引線電阻的影響，是工業過程控制中的***常用的。   

○3四線制：在熱電阻的根部兩端各連接兩根導線的方式稱為四線制，其中兩根引線為熱電阻提供恒定電流I，把R轉換成電壓信號U，再通過另兩根引線把U引至二次儀表。可見這種引線方式可******消除引線的電阻影響，主要用于高精度的溫度檢測。   

熱電(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)(zu)(zu)采用(yong)三線(xian)(xian)(xian)制(zhi)(zhi)接法。采用(yong)三線(xian)(xian)(xian)制(zhi)(zhi)是為(wei)了(le)消除連接導線(xian)(xian)(xian)電(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)(zu)(zu)引起(qi)的(de)(de)測(ce)(ce)量誤(wu)差(cha)。這(zhe)是因為(wei)測(ce)(ce)量熱電(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)(zu)(zu)的(de)(de)電(dian)(dian)(dian)(dian)(dian)路一般是不平衡電(dian)(dian)(dian)(dian)(dian)橋。熱電(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)(zu)(zu)作為(wei)電(dian)(dian)(dian)(dian)(dian)橋的(de)(de)一個橋臂電(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)(zu)(zu)，其連接導線(xian)(xian)(xian)（從熱電(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)(zu)(zu)到(dao)中控室）也成為(wei)橋臂電(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)(zu)(zu)的(de)(de)一部分(fen)，這(zhe)一部分(fen)電(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)(zu)(zu)是未知的(de)(de)且隨環境溫度(du)變(bian)化，造成測(ce)(ce)量誤(wu)差(cha)。采用(yong)三線(xian)(xian)(xian)制(zhi)(zhi)，將(jiang)導線(xian)(xian)(xian)一根接到(dao)電(dian)(dian)(dian)(dian)(dian)橋的(de)(de)電(dian)(dian)(dian)(dian)(dian)源(yuan)端，其余兩根分(fen)別接到(dao)熱電(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)(zu)(zu)所(suo)在的(de)(de)橋臂及與(yu)其相鄰的(de)(de)橋臂上，這(zhe)樣消除了(le)導線(xian)(xian)(xian)線(xian)(xian)(xian)路電(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)(zu)(zu)帶來的(de)(de)測(ce)(ce)量誤(wu)差(cha)。