Thermocouple vs. RTD vs. Thermistor: Qhov kawg Sensor Sib piv Guide

Thermocouple vs. RTD vs. Thermistor: Qhov kawg Sensor Sib piv Guide

Xaiv qhov ntsuas kub zoo tuaj yeem xav tias nyuaj. Txawm hais tias nws yog rau lub qhov cub ua haujlwm, cov txheej txheem tseem ceeb, lossis kev saib xyuas ib puag ncig, cov lus nug tseem nyob: lub tshuab twg muab qhov kev ua tau zoo tshaj plaws rau kev xav tau tshwj xeeb? Cov lus teb feem ntau yog nyob rau hauv kev nkag siab txog lub zog tseem ceeb thiab kev lag luam - tawm ntawm peb qhov sib tw tshaj plaws: qhovthermocouple, RTD, thiab thermistor.

Nkag siab cov neeg ua si: Ib qho nrawm nrawm

Ntawm nws lub siab, txhua lub sensor ua haujlwm ntawm lub cev sib txawv. Athermocoupleyog remarkably yooj yim thiab robust. Nws muaj ob qhov sib txawv ntawm cov hlau hlau sib txuas ntawm ib qho kawg (kev ntsuas kev sib tshuam). Qhov kev sib tshuam no tsim ib qho hluav taws xob me me, hu ua Seebeck voltage, uas hloov pauv qhov ntsuas kub. Tsis xav tau lub zog sab nraud los tsim cov teeb liab no, txawm tias nws yuav tsum tau ntsuas qhov tseeb. Qhov tseem ceeb takeaway?Thermocouplesmuaj ntau yam, npog qhov kub thiab txias ntau yam (los ntawm -200℃mus rau ntau tshaj 1700 degree, nyob ntawm seb hom), thiab feem ntau raug nqi thiab siv tau ntev txaus rau qhov chaw hnyav.

Resistance Temperature Detectors (RTDs), feem ntau yog ua los ntawm siab -purity platinum, ua hauj lwm ntawm lub hauv paus ntsiab lus sib txawv: cov hluav taws xob tsis kam ntawm cov hlau hloov nyob rau hauv ib tug heev linear thiab rov ua dua nrog kub. Lawv muab qhov tseeb thiab kev ruaj ntseg zoo tshaj qhov nruab nrab (kwv yees -200℃txog 600℃). Thermistors yog semiconductor-raws li cov khoom siv uas nws tsis kam hloov pauv nrog qhov kub thiab txias. Qhov no ua rau lawv rhiab heev rau qhov ntsuas kub me me nyob rau hauv ib qho kev txwv (feem ntau -80℃txog 150 degree), tab sis lawv cov lus teb tsis yog linear.

Kev sib piv cov tswv yim: Ua qhov kev xaiv zoo

Yog li, qhov twg yog "zoo tshaj"? Hauv kev xyaum, kev xaiv tsis tshua muaj txog ib tus yeej zoo tshaj plaws, tab sis yog hais txog cov cuab yeej tsim nyog tshaj plaws rau txoj haujlwm.

Rau qhov kub thiab txias, mechanical ruggedness, thiab teb ceev ceev, lubthermocouplefeem ntau yog qhov kev xaiv ua ntej. Nws tus kheej- lub zog muaj zog thiab kev tsim kho yooj yim ua rau nws zoo tagnrho rau cov cua sov, lub tshuab nqus tsev, lossis cov txheej txheem loj. Txawm li cas los xij, lawv yuav tsum muaj kev siv nyiaj ruaj khov rau kev sib txuas lus (cov nyiaj sib txuas txias) rau kev nyeem kom raug, thiab cov teeb liab xov hlau yuav tsum siv cov khoom sib txuas txuas txuas ntxiv kom tsis txhob muaj kev qhia tshiab, yuam kev - ua rau kev sib tshuam.

Thaum precision, ruaj khov, thiab rov ua dua ntawm qhov nruab nrab yog qhov tseem ceeb, RTD feem ntau nyiam. Hauv cov chaw kuaj mob, cov txheej txheem huv, lossis cov ntawv thov uas qhov yuam kev me me raug nqi, qhov raug zoo dua ntawm qhov siab - zoo platinum RTD pom tseeb nws cov nqi siab dua thiab lub sij hawm teb qeeb me ntsis piv rau ibthermocouple.

Thermistors ua tau zoo nyob rau hauv daim ntawv thov uas yuav tsum tau siab rhiab heev nyob rau hauv ib tug nqaim band. Lawv feem ntau pom muaj nyob rau hauv cov khoom siv, cov khoom siv kho mob, lossis kev tswj hwm ib puag ncig uas kuaj xyuas qhov ntsuas kub ntawm feeb yog qhov tseem ceeb. Lawv cov kev txwv tseem ceeb yog qhov ua haujlwm nqaim thiab qhov xav tau ntawm cov teeb liab linearization.

Kev txiav txim siab tseem ceeb thiab teeb meem kom zam

Kev paub dhau los qhia tau hais tias kev tsom mus rau tus nqi pib lossis ib qho kev qhia tshwj xeeb tuaj yeem ua rau - teeb meem ntev. Ob peb cov lus qhia siv tau tuaj yeem pab:

Qhov tseeb vs. Stability:Ib lub sensor tuaj yeem ua tau "tshwj xeeb" thaum lub sijhawm ntsuas ntsuas tab sis tuaj yeem "drift" dhau sijhawm.Thermocouplestuaj yeem txav tau vim muaj tshuaj hloov pauv hauv cov hlau hlau ntawm qhov kub thiab txias, thaum siab -RTDs zoo tau txais txiaj ntsig rau lawv lub sijhawm ntev - ruaj khov.

System complexity:Qhov yooj yim tso zis ntawm RTD (tsis kam) lossis thermistor feem ntau yooj yim dua rau cov qauv ntsuas ntsuas nrog cov kev daws teeb meem siab. Tsawg-millivolt teeb liab los ntawm athermocoupleNws muaj kev cuam tshuam ntau dua rau cov suab nrov ntawm cov xov hlau ntev ntev thiab yuav tsum muaj lub tshuab xa hluav taws xob ntau dua lossis ntsuas ntsuas.

Cov ntsiab lus Durability:Thaum athermocouplesheath tuaj yeem tiv taus kev tsim txom lub cev thiab kub kub, cov xov hlau sab hauv tuaj yeem degraded los ntawm qee qhov cua (txo lossis oxidizing). Ib qho RTD's platinum element yog cov tshuaj inert ntau dua tab sis tuaj yeem raug puas los ntawm kev co lossis lub cev poob siab yog tias tsis nyob hauv tsev zoo.

Cov Lus Qhia Tseem Ceeb

Yog tsis muaj universal tov. Qhov zoo tshaj plaws sensor tshwm sim los ntawm kev tshuaj xyuas meej ntawm daim ntawv thov cov kev xav tau tshwj xeeb: qhov xav tau qhov kub thiab txias, qhov tsim nyog raug thiab kev ruaj ntseg kam rau ua, lub sij hawm teb, ib puag ncig (kev vibration, tshuaj lom neeg raug), thiab tag nrho cov peev txheej.

Qhov kev txiav txim siab tsis zoo no- ua yog qhov tseeb qhov kev pom kev ua haujlwm tsis muaj nuj nqis. Ib yam li cov qauv tsim vaj tsev sib txawv thov kom haum rau HVAC cov kev daws teeb meem, cov ntawv thov kev lag luam nyuaj lossis kev lag luam tau txais txiaj ntsig zoo heev los ntawm kev cai - tsim cov tswv yim pom zoo. Xaiv qhov zoo sensor-yog nws yog ruggedthermocouple, ib qho RTD meej, lossis tus thermistor rhiab heev - thiab kev sib koom ua ke kom raug nyob rau hauv qhov kev tswj hwm loj dua yog qhov tseem ceeb rau kev ua tiav kev tswj xyuas cov txheej txheem thermal, txhim khu kev qha, thiab kev nyab xeeb. Kev ua tiav kev ua tiav hinges ntawm kev sib piv cov sensor lub zog muaj zog ncaj qha rau cov kev sib tw tshwj xeeb ntawm txoj haujlwm ntawm tes.