壓(ya)力(li)(li)(li)變(bian)送器(qi)是(shi)工(gong)業(ye)(ye)(ye)實踐中為常用(yong)的(de)一(yi)種傳感器(qi)，其(qi)廣泛應用(yong)于各種工(gong)業(ye)(ye)(ye)自控環境(jing)，涉及水(shui)利水(shui)電、鐵路交通(tong)、智(zhi)能建筑、生產自控、軍工(gong)、石化、油(you)井、電力(li)(li)(li)、船舶(bo)、機床、管道(dao)等眾多(duo)行業(ye)(ye)(ye)。下面就(jiu)簡單(dan)介紹一(yi)些常用(yong)壓(ya)力(li)(li)(li)變(bian)送器(qi)的(de)原理及其(qi)應用(yong)、壓(ya)力(li)(li)(li)變(bian)送器(qi)是(shi)用(yong)于測量液體、氣體或蒸汽的(de)液位、密(mi)度和壓(ya)力(li)(li)(li)，然后將壓(ya)力(li)(li)(li)信(xin)號轉變(bian)成4～20mA DC信(xin)號輸出。
壓(ya)力(li)(li)(li)變(bian)(bian)送(song)器(qi)(qi)(qi)主要(yao)有(you)電容式壓(ya)力(li)(li)(li)變(bian)(bian)送(song)器(qi)(qi)(qi)和擴(kuo)散硅壓(ya)力(li)(li)(li)變(bian)(bian)送(song)器(qi)(qi)(qi)，陶瓷壓(ya)力(li)(li)(li)變(bian)(bian)送(song)器(qi)(qi)(qi)，應變(bian)(bian)式壓(ya)力(li)(li)(li)變(bian)(bian)送(song)器(qi)(qi)(qi)等。壓(ya)力(li)(li)(li)變(bian)(bian)送(song)器(qi)(qi)(qi)根據測(ce)壓(ya)范(fan)圍可(ke)分成一(yi)般壓(ya)力(li)(li)(li)變(bian)(bian)送(song)器(qi)(qi)(qi)（0.001MPa～35MPa）和微(wei)差(cha)壓(ya)變(bian)(bian)送(song)器(qi)(qi)(qi)（0～1.5kPa），負壓(ya)變(bian)(bian)送(song)器(qi)(qi)(qi)三(san)種。
壓(ya)(ya)(ya)力(li)(li)(li)變(bian)(bian)送器(qi)的(de)(de)主要作用(yong)把壓(ya)(ya)(ya)力(li)(li)(li)信號傳到電(dian)子設備，進而在計算機(ji)顯示壓(ya)(ya)(ya)力(li)(li)(li)其原理大(da)致是：將水壓(ya)(ya)(ya)這(zhe)種(zhong)壓(ya)(ya)(ya)力(li)(li)(li)的(de)(de)力(li)(li)(li)學(xue)信號轉變(bian)(bian)成電(dian)流(liu)（4-20mA）這(zhe)樣(yang)的(de)(de)電(dian)子信號壓(ya)(ya)(ya)力(li)(li)(li)和電(dian)壓(ya)(ya)(ya)或(huo)電(dian)流(liu)大(da)小成線性關(guan)系(xi)，一般是正(zheng)比關(guan)系(xi)。所以，變(bian)(bian)送器(qi)輸出的(de)(de)電(dian)壓(ya)(ya)(ya)或(huo)電(dian)流(liu)隨壓(ya)(ya)(ya)力(li)(li)(li)增(zeng) 大(da)而增(zeng) 大(da)由此得出一個壓(ya)(ya)(ya)力(li)(li)(li)和電(dian)壓(ya)(ya)(ya)或(huo)電(dian)流(liu)的(de)(de)關(guan)系(xi)式壓(ya)(ya)(ya)力(li)(li)(li)變(bian)(bian)送器(qi)的(de)(de)被測介質的(de)(de)兩(liang)(liang)種(zhong)壓(ya)(ya)(ya)力(li)(li)(li)通入高、低兩(liang)(liang)壓(ya)(ya)(ya)力(li)(li)(li)室，低壓(ya)(ya)(ya)室壓(ya)(ya)(ya)力(li)(li)(li)采用(yong)大(da)氣壓(ya)(ya)(ya)或(huo)真空，作用(yong)在δ元（即敏感元件）的(de)(de)兩(liang)(liang)側隔(ge)離膜片(pian)上，通過隔(ge)離片(pian)和元件內的(de)(de)填充液傳送到測量膜片(pian)兩(liang)(liang)側。
壓力(li)變送器是由測量膜片(pian)(pian)(pian)與兩側(ce)絕緣片(pian)(pian)(pian)上的(de)電(dian)極各(ge)組成一個電(dian)容器。當兩側(ce)壓力(li)不(bu)一致(zhi)時，致(zhi)使測量膜片(pian)(pian)(pian)產生位(wei)移，其(qi)位(wei)移量和壓力(li)差成正比，故(gu)兩側(ce)電(dian)容量就(jiu)不(bu)等，通過振(zhen)蕩和解調(diao)環節。
1、壓力變送器具有工作(zuo)可靠、性能穩定等特點；
2、專用V/I集(ji)成電路，外(wai)圍(wei)器(qi)件(jian)少，可靠(kao)性高，維護簡(jian)單、輕(qing)松，體積小、重(zhong)量輕(qing)，安(an)裝(zhuang)調(diao)試極為方便；
3、鋁合金壓鑄外殼，三端隔(ge)離，靜電噴塑保(bao)護層(ceng)，堅(jian)固耐用；
4、4-20mA DC二線制信號(hao)傳(chuan)(chuan)送，抗干擾能(neng)力(li)強，傳(chuan)(chuan)輸距離(li)遠；
5、LED、LCD、指針三(san)種指示表頭，現(xian)場(chang)讀數十分方便。可用(yong)于測量粘稠、結晶和腐(fu)蝕性(xing)介質(zhi)；
6、高準(zhun)確度(du)，高穩定性(xing)(xing)。除進口原裝傳感器已用激光修正外，對整(zheng)機(ji)在使(shi)用溫度(du)范圍內的綜合性(xing)(xing)溫度(du)漂移(yi)、非線性(xing)(xing)進行精細補償。
