Capacitive sensor: apparatus thiab ntsiab cai ntawm lub lag luam. Capacitive sensors: daim ntawv thov

Niaj hnub nimno kev lag luam, thiab txhua hnub tib neeg tib neeg kev ua ub no, dhau lawm, nws yog tsis yooj yim sua xav txog tej yam tsis muaj tag nrho cov xaiv ntawm hluav taws xob. Lawv pab tau peb nyob rau hauv txhua txoj kev, thiab ib co raug ua hauj lwm rau ua tsis tau zoo tsis tau lawv. Rau cov neeg "pab" yuav tsum muaj xws li ib tug capacitive sensor.

Yog li ntawd hu ua converters ua los ntawm parametric hom. Ntsuas ntawm ib tug ntim xws li yog ua los ntawm variations ntawm capacitance thaum hloov ntawm ib co tseem ceeb tsis. Cias muab, kwv yees li hloov nyob rau hauv capacitance nyob rau hauv tus ntawm ib co lwm yam.

Cov kev khiav hauj lwm hauv paus ntsiab lus ntawm cov capacitive sensor

Hais tias yog dab tsi tus capacitive sensors. Lub hauv paus ntsiab lus ntawm cov lag luam lawv yog tsis yog li ntawd nyuaj, tab sis kom to taub tias koj yuav tsum tau paub ib yam dab tsi. Yuav pib nrog peb rov qab lub hauv paus ntsiab lus ntawm kev txiav txim capacitance ntawm lub capacitor. Daim ntawv no yog qhia los ntawm cov nram qab no mis:

C = εεₒS / δ.

Qhov no qhia yog lub npe hu rau ntau los ntawm lub tsev kawm ntawv physics cov hoob kawm, tab sis nws yuav tsis ua mob ua tshiab koj nco thiab rov qab, uas txhais tau tias txhua tus lub zog:

• S - thaj tsam ntawm lub capacitor daim hlau.
• E - txheeb ze permittivity ntawm lub dielectric khoom siv nyob rau hauv capacitor tsim.
• εₒ - raws li nyob rau hauv physics rau denote permittivity ntawm qhov chaw dawb.
• δ - ces nws yuav tsum xaiv los yog lub thickness ntawm cov dielectric phaj, los yog qhov kev ncua deb ntawm lub ob peb khaubncaws sab nraud povtseg ntawm cov ntaub ntawv uas.

Yog li, los ntawm cov saum toj no mis uas tus capacitance hloov tau yooj yim. Suffice nws sov ua licas ua rau lub cheeb tsam ntawm lub phaj ntawm dielectric khoom, ib tug deb ntawm cov phiaj los yog ncaj nraim nrog cov permeability siv nyob rau hauv qhov siv thiab ua cov khoom. Raws li, qhov kev xaiv ntawm kev nqis nyob nyuaj rau daim ntawv teev cov kev pab raws qib uas tus ntaus ntawv designers tau teem cia.

Yog li, peb txawm yuav ua ib tug capacitive sensor nrog koj ob txhais tes, raws li ib tug constructive taw tes ntawm view nws yog - ib txwm ca los cylindrical capacitor, ib phaj uas yog lossi muaj ib tug tswj lub zog nyob rau hauv qhov chaw, uas ua rau yus mus rau ib tug kev hloov nyob rau hauv capacitance. Nws yuav tsum tau nco ntsoov tias saum toj no mis yog siv tau yog hais tias koj yog kiag li tsis ntug los. Peb mam li tham ntxiv txog qhov no nyob rau hauv lub kawg ntawm ntu no tsab xov xwm.

Nws yuav tsum tau paub hais tias xws li hluav taws xob khoom siv yog siv feem rau ntsuas lub angular thiab linear displacements ntawm cov khoom, xam qhov luaj li cas, tus ua ntawv thov ua hauj lwm, humidity, concentration ntawm active tshuaj thiab lwm yam ntxwv. Nrog kev xav txog cov yam ntxwv ntawm tej yam muaj cov nqe lus nug, ces hais tias bales no yog ua los dav hlau-thaum uas tig mus, nyob rau hauv cylindrical housings nrog pin electrodes, nrog ib tug hauv ob sab phlu ntawm ib tug dielectric cov khoom, thiab txawm tsis tau nws.

Ntawm no yog yuav ua li cas khiav lag luam capacitive sensors. Lub hauv paus ntsiab lus ntawm cov lag luam ntawm ib co ntawm lawv yuav tsum paub nyob rau hauv zoo meej. Nyob rau hauv no tsab xov xwm peb muab ib co qauv uas yuav pab tau rau koj.

Formula rau piav qhia txog lub hauv paus ntsiab lus ntawm cov lag luam ntawm tej hom sensors

Theem sensor nrog tau variation ntawm lub square dielectric daim hlau yuav tsis haum yooj yim piav siv cov nram qab no kab zauv:

C = εεₒaH / δ.

Los ntawm "X" nyob rau hauv cov ntaub ntawv no yog hais txog rau qhov ntev ntawm lub overlap ntawm electrodes siv. Raws li, "ib tug" qhia lub dav ntawm cov phiaj ntawm lub capacitor. Nws yuav tsum tau muab sau tseg hais tias xws li pab kiag li lawm tau thov nyob rau hauv ntau yam teb kev lag luam, qhov uas lawv yuav siv kom meej ntsuas ntawm angular qhov tseem ceeb. peev xwm ntawm lub transducer nyob rau hauv xws li ib tug cov ntaub ntawv no muaj nyob ntawm cov nram qab no qhia:

C = εεₒ (r₂- r₁) / 2δ * (φₒ-φ).

Nyob rau hauv kev txiav txim los yog ntsuas lub rhiab heev, koj yuav tsum tau siv ib tug me ntsis txawv mis:

K = εεₒ (r₂- r₁) / 2δ.

Cia peb saib dab tsi yog meant los ntawm cov neeg variables uas yog ib feem ntawm cov equations:

• r₁ - puab vojvoog ntawm lub condenser phiaj no;
• r₂ - txheej vojvoog ntawm tib phaj;
• φ - ntsuas ntawm lub caij (tiag tiag) tus nqi ntawm cov tshooj kaum sab xis;
• φₒ - thawj zaug nqi ntawm cov tshooj kaum sab xis.

Thaum kawg, peb piav qhia txog cov zauv qhia uas piav txog cov kev khiav hauj lwm hauv paus ntsiab lus ntawm cov capacitive gauge nrog adjustable cua kis:

C = εεₒS / (δₒ-X).

Twv, ib tug thawj clearance δₒ to taub, tsab ntawv X yog tus nqi qub xaav ntawm lub phaj. Xyuam xim! Txij li thaum zoo li qub yam ntxwv yog tsis nruj me ntsis linear, feem ntau cov theem sensor ntawm lub hom siv los ntsuas me me displacements, uas yuav tsis ntau tshaj qhov muaj nuj nqis 0,1δₒ. Lawm, cov pab kiag li lawm no mas demanded nyob rau hauv precision engineering, qhov twg txawm me uas tsis muaj peev xwm ua rau heev loj teeb meem.

Qhov twg yuav lawv yuav siv li cas?

Cov cheeb tsam ntawm tau daim ntawv thov yog tsis tshua muaj neeg. Yog li, nyob rau hauv txhua industries tau raws li qhov hauj lwm, uas yog tswj los ntawm cov pab kiag li lawm. Lawv yuav siv los tswj lub txhaws ntawm lub ntau yam tso tsheb hlau luam, thiab lawv txheem yuav ua tau kua, gaseous los yog particulate (gas sensor).

Lub loj heev uas muaj thiab ib txwm tib neeg muaj kev ua si yog ntau dua, ntau txhim khu kev qha thiab yooj yim rau tsim xws kiag li lawm. Los ntawm cov ua ke ntawm cov tsos mob no, lawv yog zoo li ntawd, hais tias lawv yuav siv tau txawm nyob rau hauv tsis tshua muaj neeg txhoj puab heev tej yam kev mob tuas roj tankers.

Tsis tas li ntawd, lub capacitive sensor tej zaum yuav siv tau raws li ib tug txwv hloov rau lub conveyor kab los yog tshuab raug khw. Nws yog tsim nyog thiab rau feem ntau muaj tseeb tso ntawm ntau yam mechanisms.

sib thooj sensors

Tab sis tam sim no nyob rau hauv zoo kawg thov sib thooj sensors, uas yog ua los ntawm raws nraim tib yam ntsiab cai. Cov kab kev los ntawm lawv cov kev siv yog txawm wider. Qhov no yog vim lub penny nqi pab kiag li lawm uas yuav ua hauj lwm nyob rau hauv txhua hom kev lag luam. Txawm li cas los, muaj raug kev lag luam nyob qhov twg no hom ntawm cov khoom yog cov feem ntau nrov:

• Control ntawm cov kua puv pob tshab ntim ua los ntawm yas los yog iav.
• Ib tug zoo xws li cov nuj nqi yog ua los ntawm lawv nyob rau hauv qhov siv thiab ua cov khoom noj khoom (xws li cov me nyuam), qhov chaw uas cov khoom tiav yog fej nyob rau hauv ntim ua los ntawm pob tshab ntawv. Nyob rau tib lub hauv paus ntsiab lus raws li thiab cov ua hauj lwm ntawm lub bale raws li ib tug capacitive roj sensor.
• Rau saib xyuas tej thaj chaw, nyob qhov twg tau tawg winding hlau.
• Tswj zoo xws li cov chaw nyob qhov twg cov cab kuj conveyor siv yuav yuav puas ntsoog.
• Ib tus zuj zus tswj lub hom ntawm cov khoom ua (hloov dua siab tshiab ntawm cov kaus poom, lam hwj, ntim).

Tsis ceeb, cov hluav taws xob yog cov feem ntau nyob rau hauv lub precision engineering, lub hwj chim tiam thiab ntau ntau lwm yam lag luam ntau yam ntawm sensors.

inclinometers

Devices uas tau ua tus nais khu xwb nyob rau hauv kuj tsis ntev los no xyoo yog me me-sized capacitive inclinometer muab kis tau tus mob hluav taws xob tso zis lub teeb liab uas nws magnitude yog ncaj qha proportional rau lub kaum sab xis sensor siv.

Cov feem ntau loj teb ntawm kev siv ntawm cov pab kiag li lawm: platform kawm tuab si lug system, kev txiav txim ntawm lub deflection thiab deformation ntawm ntau hom ntawm kev them nyiaj yug beams, raws li zoo raws li leej tswj ntawm txoj kev, railway khiav txawv nyob rau theem ntawm lawv siv.

Ntxiv mus, siv xws li txiav txim seb tus yob ntawm hnyav tsheb thauj khoom thiab lwm yam tsheb, elevators thiab muaj excavators thiab ascertain cov neeg kawm ntawv ntawm angular xaav rau ua liaj ua teb thiab muaj cov cav tov tshwj xeeb loj.

Heev tseem ceeb capacitive sensors roj theem nyob rau hauv cov roj kev lag luam. Lawv yog siv txawm nyob rau hauv lub supertankers uas muaj nyob rau hauv ib lub dawm kaum thiab pua pua txhiab tus tons ntawm ua kom zoo roj khoom. Cov pab kiag li lawm yog cov tsis tshua zoo txawm nyob rau hauv heev tshaj tsim ntawm condensate thiab ib tug high degree ntawm hmoov av ntau lawm cheeb tsam (tib yam roj sensor).

Lawv nrhiav tau lawv cov kev siv nyob rau hauv cov kev ntsuas qhov tseem ceeb ntawm lub meej thiab txheeb ze siab ntau li zoo raws li lub thickness ntawm cov dielectric khoom, uas yog tsis tshua muaj ib qho tseem ceeb nyob rau hauv yuav luag tag nrho cov lag luam uas tiag tiag haib capacitors yog siv.

Lub ntsiab zoo ntawm capacitive sensors

Nws yuav tsum tau muab sau tseg tias capacitive sensor muaj ntau yam zoo thaum muab piv nrog yam khoom zoo li uas yog tsim nyob rau sib txawv dog dig tej ntsiab cai. Wb sau lub ntsiab zoo ntawm cov Kip:

• Nyob rau hauv manufacturing, lawv yog cov tsis tshua yooj yim. Nyob rau hauv tas li ntawd, lub feem ntau yooj yim thiab pheej yig ntaub ntawv yuav siv tau nyob rau hauv lawv cov khoom. Txawm capacitive roj theem sensors siv nyob rau hauv lub roj av lag luam tseem ceeb khoom muaj tsis tshua muaj neeg coj loj muaj tus nqi qis tshaj tau theem ntawm kev noj ntawm hluav taws xob. Nrog rau tag nrho cov yam ntxwv, lawv txawv zoo heev txog qib uas rhiab heev, uas yog feem ntau unattainable rau qhov ntau kim kiag li lawm.
• Nyob rau hauv hauv paus ntsiab lus, nws yuav ua tau ib tug capacitive sensor nrog koj ob txhais tes, siv raws li nws puag tej yam ntau los yog tsawg dua txhim khu kev qha thiab zoo muaj capacitor.
• Rau cov neeg uas lawv muaj (heev tsis tshua muaj siv ib tug tam sim no collector), uas yog tsis tshua muaj heev rau lub chaw ua hauj lwm nyob rau hauv tej yam kev mob ntawm high hmoov av thiab cov av noo.
• ntev heev kev pab cuam lub neej, lub tsev pheej tswj "recapture" lawv tsis muaj nqi. Raws li, qhov capacitive sensor (tus nqi uas yog nyob rau hauv ntau 1200-1700 rubles) yog tsis tshua muaj txiaj ntsim tshaaj.
• Kev tsiv lub rooj noj feem ntawm tus ntaus ntawv yuav tsum tau ua kuj ceeb tias me ntsis kev rau siab.
• Tus ntaus ntawv yog heev yooj yim mus ua ke nrog luag tag nrho cov pawg ntawm cov khoom uas yog siv nyob rau hauv industrial ua ub no.

kev tsis zoo

Tu siab, txhua capacitive sensor muaj tej yam drawbacks, uas mus rau ib tug tej yam raws li cov nyom lub thoob plaws siv ntawm no hom ntawm cov khoom. Peb sau lawv nyob rau hauv ntau yam:

• hloov dua siab tshiab zoo tshaj (i.e., kis tau tus mob) yog tus tsis muaj.
• Me loj thiab simplicity ntawm tsim pab rau lub fact tias lub nominated heev xav tau nyob rau hauv qhov zoo tshaj ntawm kev kuaj pab kiag li lawm.
• Zoo capacitive theem sensor (thiab lwm yam zoo xws xab seev) yuav khiav lag luam zoo tsuas yog nyob rau ib zaus ntau ntau dua li cov txheej txheem nqi ntawm 50 Hz.

ib qho tseem ceeb Cov ntawv ceeb toom

Txawm li cas los, tag nrho yog tsis yog li ntawd phem. Muaj ntau manufacturers nrhiav zoo heev shielding yam ntxwv ntawm cov sensors los ntawm kev ua me kev hloov nyob rau hauv lawv cov qauv. Raws li rau lub zaus ntawm kev siv, nyob rau hauv xyaum lawv qhia tau zoo heev nyob rau hauv ntau muaj tus nqi ntawm 400 Hz.

Peb twb tham txog loyalty rau qhov yooj yim mis yog hais tias uas raug nqi ntau cov ntug nyhuv. Tab sis nws yog pab tau paub hais tias nws muaj peev xwm tiag tiag muaj ib tug tsis ntxim xwb nyob rau hauv cov kev tshwm sim hais tias qhov kev ncua deb ntawm lub dielectric daim hlau yog piv rau lawv tus kheej me me. Ntxiv mus, yam tsis zoo zoo yuav lom zem ntau neutralize tsuas siv lub khwb lub nplhaib. Nyob rau hauv cov ntaub ntawv no, tej yam uas ciam teb los yuav tsis hloov zoo tshaj siv daim hlau.

Ib zaug ntxiv, peb nco ntsoov hais tias tus tib siab sensors yog yus muaj los ntawm ib tug zoo kawg li simplicity, uas tso cai rau koj los ua ib tug marvellously ruaj khov, ruaj thiab tsis muaj nqi qauv. Yog hais tias koj xaiv lub geometric ntev siv dielectric yog siv nyob rau hauv qhuav ntawm xws li ib tug capacitor ntaub ntawv tsis tau tshwj xeeb kev txhawj xeeb.

Yog li, kom tos tus hlau stamp rau qhov siv thiab ua cov sensor vaj tse, nws yog suab negligible txawm muaj zog kub hloov mus hloov los uas yuav ua raug nyob rau hauv ib tug kev hloov nyob rau hauv capacitance ntawm cov ntaus ntawv thiab nws cov tsis txaus readings. Ntawm cov hoob kawm, qhov no tsis obviate qhov yuav tsum tau ua txhij txhua raug rho tawm siab sensors thiab lwm yam xws li kev ntsuas ntawm kev txhoj puab heev tej yam. Txawm lawv simplicity, cov pwm thiab kom theem ntawm hluav taws xob yuav cuam tshuam rau lub ntseeg ntawm lub ntaus ntawv.

kev faib ntawm sensors

Siv nyob rau hauv muaj dab rau lawv lawm cia koj mus muab tag nrho cov hom ntawm sensors ua rau ob pawg loj: odnoemkostnye thiab dvuhemkostnye. Cov yav tas zoo yog muab faib ua differential thiab poludifferentsialnye. Cia peb xav txog lawv nyob rau hauv ntau yam.

Odnoemkostny ntaus ntawv. Nyob rau hauv rooj plaub no tus capacitive sensor Circuit Court tsis tshua muaj neeg yooj yim, vim lawv lub ntsiab yog lub feem ntau capacitor nrog nce mus nce los capacitance. Tu siab, txawm tias ib tug me ntsis ntau zog cov av noo thiab kub muaj nyob rau hauv cov neeg ntawm indications heev tangible tej yam. Vim li no, muaj ntau ntau yam sensors feem ntau malfunction. Yuav kom neutralize lub qhov ntau ntawm cov teeb meem, nws yog tsim nyog los siv differentiated qauv.

Dvuhemkostny sensor. Ua tau, nws yog xws li ib tug differentiated qauv. Nws yog feem ntau tau kom tau raws li lub capacitive theem sensor yog manufactured los ntawm xws li ib tug tswvyim. Cov pab kiag li lawm yog tauj los ntawm lub ntsiab drawbacks ntawm yav tas los qauv, tiam sis yuav tau lawv tus kheej kev qaug zog. Qhov loj tshaj disadvantage yog cov yuav tsum tau siv ob los yog peb shielded nyob ntawm tej ntawm lub ntaus ntawv nws tus kheej thiab qhov chaw, vim hais tias tsuas nyob rau hauv no yav tas yuav suppress lub thiaj li hu ua cab capacitance.

Txawm li cas los, ib tug ncaj sophisticated tswvyim ntawm capacitive sensors nyob rau hauv cov ntaub ntawv no nws yog ib qho yooj yim mus tsis quav ntsej, vim hais tias nyob rau hauv rov qab koj tau txais ib tug tsis tshua muaj tseeb thiab rhiab ntaus ntawv.

constructing sensors tseem

Nyob rau hauv feem ntau (los ntawm tus tsim taw tes ntawm view) lub creation ntawm xws li yog problematic. Qhov no yog tshwj xeeb tshaj yog muaj tseeb thaum twg koj xav los ua ib tug sensor nrog nce mus nce los theem ntawm muaj peev xwm. Txawm li cas los, kev qhia tau hais tias hais tias muaj ntau ntawm cov teeb meem no daws yuav luag tseeb calibration thiab kev kawm ntaub ntawv siv nyob rau hauv ntau lawm. Feem ntau cov feem ntau cov teeb meem kev nyuaj siab los ntawm producers dvuhemkostnyh sensors.

Nyob rau hauv dav dav, lub tseem ntawm no hom ntawm xab pab kiag li lawm yog hais tias lawv muaj peev xwm yuav sawv cev raws li ib tug dimensionless piv ntawm ob lub cev ntau (ntim) uas muaj ib tug leej lub cev qhia thiab ntsiab lus. Yog li ntawd hais tias lawv muaj peev xwm yuav xyuam xim hu ua "probes lub kev sib raug zoo." Qhov kom zoo dua ntawm cov pab kiag li lawm (lawv loj loj ntxiv rau!) Yog hais tias lawv feem ntau yuav tsis muaj nyob rau hauv nws tsim ib co txheej txheem kev ntsuas uas txias tej kev ntseeg nyob rau hauv yeej huab lub sijhawm thiab tej yam kev mob.

Characterization ntawm linear encoders

Tag nrho cov uas tsis yog hluav taws xob qhov tseem ceeb, uas yog feem ntau yuav tsum tau mus tswj nyob rau hauv ib tug muaj ib puag ncig, nws yog tsis tshua muaj ntau haiv neeg thiab multifaceted. Ib tug tseem ceeb ib feem ntawm cov kev ntsuas uas yog yuav muaj kev nruj ntawm lwm yam uas, ua angular thiab linear taw txawm ntau yam ntawm tej chaw uas nyob rau hauv qhov chaw. Yog hais tias koj siv ib tug capacitor uas muaj kiag li niaj hnub hluav taws xob field nyob rau hauv cov kis, nws tsis yog li ntawd tsis yooj yim rau ua hluav taws xob sensors ob ntawm lub nram qab no:

• Nyob rau hauv uas thaj tsam ntawm lub electrodes yog nce mus nce los.
• Cov neeg uas muaj ib tug kuj tsis paub meej kis ntawm tus electrodes.

Nws yog ib qho yooj yim to taub tias thawj hom yog tsim rau kev kho cov kev tawm tsam loj tiag tiag, thaum nrog kev pab ntawm ob hom ib qho peev xwm txawm pom xws li taw ntawm lub cev nyob rau hauv qhov chaw, qhov siab ntawm uas tsuas yog ob peb lub microns!

Lub qhov nqus tawm sab nrauv

Feem ntau, los ntawm kev tsim thiab lub hom phiaj, lawv yuav luag txhua yam zoo tib yam rau hom uas yog xam xwb. Qhov zoo sib xws yog qhov tseeb uas cov sensors nrog thaj tsam ntawm cov electrodes kuj yuav tsum raug siv rau kev ntsuam loj, thiab nrog ib qhov deb ntawm cov electrodes lawv tus kheej rau cov me me. Raws li txoj cai, xws li cov cuab yeej ua los ntawm kev sib txuam, nrog rau qhov hloov ntawm cheeb tsam ntawm daim ntawv tu cov plhaub.

Kom ua tau zoo li no, tus thawj electrode yog txuas rau cov ncej txav, raws li txoj kev hloov uas nws hloov nws txoj hauj lwm ntsig txog qhov thib ob, uas kom muaj kev hloov hauv cheeb tsam overlapping ntawm dielectric daim hlau nyob rau hauv lub capacitor. Lawm, tib lub sij hawm qhov kev hloov pauv ploj lawm.

Cov lus xaus

Yog li ntawd, peb tau soj ntsuam cov cwj pwm ntawm cov cuab yeej ntawm cov qib no, kawm txog cov cheeb tsam ntawm lawv daim ntawv thov, cov yam ntxwv ntawm tus tsim, txoj cai ntawm kev lag luam thiab kev nrhiav kev pab tau. Raws li koj nkag siab tau los ntawm tsab xov xwm, lub zog ntawm qhov muaj zog capacitive thiab lawv cov chaw siab heev yog raws li tus nqi txaus nyiam ntawm cov khoom siv thiab lub neej ntev kev ua haujlwm txawm nyob hauv tej qhov chaw nyuaj.

Tag nrho qhov no yog ua tau vim yog qhov tseeb, los ntawm qhov kev xam pom, tag nrho cov meters no tsuas yog tus qauv uas siv tus qauv, uas yog ib yam uas txawv ntawm kev siv lawv. Txawm li cas los xij, koj tus kheej tuaj yeem nrhiav tau qhov no los ntawm kev rov los xyuas dua ntawm cov qauv kev ua lej uas feem ntau pom cov qauv ntawm kev ua haujlwm ntawm instrumentation.