Thaum siv rau kev saib xyuas kev lag luam, cov sensors tuaj yeem sau cov xwm txheej ntawm ib puag ncig. Cov teeb liab sensor siv hauv cov txheej txheem los taug qab cov kev hloov pauv ntawm thaj chaw uas raug saib xyuas. Ob qho tib si digital thiab analogue teeb liab tuaj yeem tshwm sim.
Feem ntau muaj hluav taws xob voltage lossis tam sim no tus nqi tsim tawm uas sib raug zoo rau cov hloov pauv lub cev uas tau saib xyuas.
Kev ua cov teeb liab analogue yog qhov yuav tsum tau ua thaum cov txheej txheem automation yuav tsum tswj hwm lossis ncav cuag cov xwm txheej uas tau teev tseg. Qhov no yog qhov tseem ceeb rau cov ntawv thov automation. Cov teeb liab hluav taws xob txheem feem ntau yog siv rau kev tsim kho txheej txheem. Cov hluav taws xob txheem analogue / voltage 0(4)...20 mA/ 0...10 V tau tsim lawv tus kheej ua kev ntsuas lub cev thiab kev tswj hwm.