• about19

Qhia koj kom paub ntau ntxiv txog POE fais fab mov!

Ntau tus phooj ywg tau nug ntau zaus seb puas yog lub zog poe ruaj khov?Dab tsi yog qhov zoo tshaj plaws cable rau poe fais fab mov?Vim li cas siv lub poe hloov mus rau lub hwj chim lub koob yees duab tseem tsis muaj zaub?thiab lwm yam, qhov tseeb, cov no muaj feem xyuam rau lub zog poob ntawm POE fais fab mov, uas yooj yim rau tsis quav ntsej hauv qhov project.
1. POE fais fab mov yog dab tsi
PoE hais txog kev xa cov ntaub ntawv rau qee qhov IP-raws li cov khoom siv (xws li IP xov tooj, wireless LAN nkag point APs, network koob yees duab, thiab lwm yam) yam tsis tau hloov pauv rau Ethernet Cat.5 cabling infrastructure uas twb muaj lawm.Tib lub sijhawm, nws tseem tuaj yeem muab DC fais fab mov tshuab rau cov khoom siv zoo li no.
PoE thev naus laus zis tuaj yeem ua kom muaj kev ua haujlwm ib txwm muaj ntawm lub network uas twb muaj lawm thaum ua kom muaj kev ruaj ntseg ntawm cov txheej txheem cabling uas twb muaj lawm, thiab txo tus nqi tsawg.
Ib qho kev ua tiav PoE suav nrog ob ntu: cov khoom siv hluav taws xob thiab cov khoom siv hluav taws xob txais.

Cov Khoom Siv Hluav Taws Xob (PSE): Ethernet keyboards, routers, hubs lossis lwm lub network hloov khoom siv uas txhawb nqa POE ua haujlwm.
Powered ntaus ntawv (PD): Hauv kev saib xyuas, nws yog lub koob yees duab network (IPC).
2. POE fais fab mov txheem
Qhov tseeb thoob ntiaj teb tus qauv IEEE802.3bt muaj ob qhov yuav tsum tau ua:
 Thawj hom: Ib qho ntawm lawv yog qhov tso zis hluav taws xob ntawm PSE yuav tsum ncav cuag 60W, lub zog ncav cuag lub zog txais khoom siv yog 51W (nws tuaj yeem pom los ntawm cov lus saum toj no tias qhov no yog cov ntaub ntawv qis tshaj), thiab lub zog poob yog 9W.
Hom thib ob: PSE yuav tsum ua kom tiav lub zog tso zis ntawm 90W, lub zog ncav cuag lub zog txais khoom siv yog 71W, thiab lub zog poob yog 19W.
Los ntawm cov txheej txheem saum toj no, nws tuaj yeem paub tias nrog kev nce ntawm cov khoom siv hluav taws xob, qhov poob ntawm lub zog tsis sib npaug ntawm cov khoom siv hluav taws xob, tab sis qhov poob tau loj dua thiab loj dua, yog li yuav ua li cas poob ntawm PSE hauv kev siv tswv yim suav nrog?
3. POE fais fab tuag
Yog li cia wb mus saib yuav ua li cas qhov poob ntawm tus neeg xyuas pib lub zog hauv tsev kawm ntawv qib siab physics suav nrog.
Joule Txoj Cai yog ib qho lus piav qhia txog kev hloov pauv ntawm hluav taws xob hluav taws xob mus rau hauv tshav kub los ntawm kev siv tam sim no.
Cov ntsiab lus yog: lub tshav kub generated los ntawm qhov tam sim no dhau los ntawm tus neeg xyuas pib yog proportional rau lub square ntawm tam sim no, proportional rau qhov tsis kam ntawm tus neeg xyuas pib, thiab proportional rau lub sij hawm nws yog energized.Ntawd yog, cov neeg ua haujlwm noj cov khoom tsim tawm hauv cov txheej txheem suav.
Kev qhia lej ntawm Joule txoj cai: Q = I²Rt (muaj feem xyuam rau txhua lub voj voog) qhov twg Q yog lub zog poob, P, Kuv yog qhov tam sim no, R yog qhov tsis kam, thiab t yog lub sijhawm.
Hauv kev siv tiag tiag, txij li PSE thiab PD ua haujlwm tib lub sijhawm, qhov poob tsis muaj dab tsi cuam tshuam nrog lub sijhawm.Qhov xaus yog tias lub zog poob ntawm lub network cable hauv POE system yog proportional rau lub square ntawm tam sim no thiab proportional rau qhov loj ntawm qhov tsis kam.Cias muab, thiaj li yuav txo tau lub hwj chim noj ntawm lub network cable, peb yuav tsum sim ua kom tam sim no ntawm cov hlau me me thiab cov kuj ntawm lub network cable me dua.Ntawm lawv, qhov tseem ceeb ntawm kev txo qis tam sim no yog qhov tseem ceeb tshwj xeeb.
Tom qab ntawd cia peb saib cov kev txwv tshwj xeeb ntawm tus qauv thoob ntiaj teb:
Nyob rau hauv tus qauv IEEE802.3af, qhov tsis kam ntawm lub network cable yog 20Ω, qhov yuav tsum tau PSE tso zis voltage yog 44V, tam sim no yog 0.35A, thiab lub zog poob yog P = 0.35 * 0.35 * 20 = 2.45W.
Ib yam li ntawd, nyob rau hauv tus qauv IEEE802.3at, qhov kev tiv thaiv ntawm lub network cable yog 12.5Ω, qhov yuav tsum tau voltage yog 50V, tam sim no yog 0.6A, thiab lub zog poob yog P = 0.6 * 0.6 * 12.5 = 4.5W.
Ob tus qauv tsis muaj teeb meem siv txoj kev suav no.Txawm li cas los xij, thaum tus qauv IEEE802.3bt mus txog, nws tsis tuaj yeem suav nrog txoj kev no.Yog tias qhov hluav taws xob yog 50V, lub zog ntawm 60W yuav tsum xav tau tam sim no ntawm 1.2A.Lub sijhawm no, lub zog poob yog P = 1.2 * 1.2 * 12.5 = 18W, rho tawm qhov poob mus txog PD Lub zog ntawm lub cuab yeej tsuas yog 42W.
4. Yog vim li cas POE fais fab tuag
Yog li ntawd yog vim li cas?
Piv nrog rau qhov xav tau tiag tiag ntawm 51W, muaj 9W tsawg zog.Yog li dab tsi raws nraim yog ua rau xam yuam kev.

Cia peb saib ntawm kab kawg ntawm cov ntaub ntawv no dua, thiab ua tib zoo saib xyuas tias tam sim no nyob rau hauv thawj IEEE802.3bt tus qauv tseem yog 0.6A, thiab tom qab ntawd saib cov twisted khub fais fab mov, peb tuaj yeem pom tias plaub khub twisted khub fais fab. cov khoom siv yog siv (IEEE802.3af, IEEE802. 3at yog powered los ntawm ob khub ntawm twisted khub) Nyob rau hauv txoj kev no, txoj kev no yuav suav hais tias yog ib tug parallel Circuit Court, tam sim no ntawm tag nrho cov Circuit Court yog 1.2A, tab sis tag nrho cov poob yog ob zaug. uas yog ob khub ntawm twisted khub fais fab mov,
Yog li, qhov poob P = 0.6 * 0.6 * 12.5 * 2 = 9W.Piv nrog rau 2 khub ntawm twisted-pair cables, txoj kev siv hluav taws xob no txuag 9W ntawm lub zog, kom PSE tuaj yeem ua rau PD ntaus ntawv tau txais lub zog thaum lub zog tso zis tsuas yog 60W.Lub zog tuaj yeem ncav cuag 51W.
Yog li ntawd, thaum peb xaiv cov khoom siv PSE, peb yuav tsum tau them sai sai rau txo qhov tam sim no thiab nce qhov hluav taws xob ntau li ntau tau, txwv tsis pub nws yuav yooj yim ua rau lub zog poob ntau dhau.Lub zog ntawm cov khoom siv PSE ib leeg tuaj yeem siv tau, tab sis nws tsis muaj nyob rau hauv kev xyaum.

Lub PD ntaus ntawv (xws li lub koob yees duab) xav tau 12V 12.95W siv.Yog tias siv 12V2A PSE, cov zis hluav taws xob yog 24W.
Hauv kev siv tiag tiag, thaum tam sim no yog 1A, qhov poob P = 1 * 1 * 20 = 20W.
Thaum qhov tam sim no yog 2A, qhov poob P = 2 * 2 * 20 = 80W,
Lub sijhawm no, qhov tam sim no ntau dua, qhov poob ntau dua, thiab feem ntau ntawm lub zog tau siv.Pom tseeb, PD ntaus ntawv tsis tuaj yeem tau txais lub zog xa los ntawm PSE, thiab lub koob yees duab yuav muaj lub zog tsis txaus thiab tsis tuaj yeem ua haujlwm ib txwm.
Qhov teeb meem no kuj tshwm sim hauv kev xyaum.Feem ntau, nws zoo nkaus li tias cov khoom siv hluav taws xob loj txaus los siv, tab sis qhov poob tsis suav.Raws li qhov tshwm sim, lub koob yees duab tsis tuaj yeem ua haujlwm ib txwm vim yog lub zog tsis txaus, thiab qhov laj thawj tsis tuaj yeem nrhiav pom.
5. POE fais fab mov tsis kam
Tau kawg, qhov tau hais los saum toj no yog qhov kev tiv thaiv ntawm lub network cable thaum lub zog xa hluav taws xob yog 100 meters, uas yog lub zog muaj nyob ntawm qhov siab tshaj plaws ntawm lub zog hluav taws xob, tab sis yog tias qhov tseeb fais fab mov nrug me me, xws li tsuas yog 10. meters, tom qab ntawd qhov kev tiv thaiv tsuas yog 2Ω, sib npaug Qhov poob ntawm 100 meters tsuas yog 10% ntawm qhov poob ntawm 100 meters, yog li nws tseem ceeb heev kom xav txog qhov siv tiag tiag thaum xaiv cov khoom siv PSE.
Kev tiv thaiv ntawm 100 meters ntawm network cables ntawm ntau yam ntaub ntawv ntawm super tsib hom twisted khub:
1. Copper-clad steel hlau: 75-100Ω 2. Copper-clad txhuas hlau: 24-28Ω 3. Copper-clad nyiaj hlau: 15Ω
4. Copper-clad tooj liab network cable: 42Ω 5. Oxygen-free copper network cable: 9.5Ω
Nws tuaj yeem pom tau tias qhov zoo dua ntawm cov cable, qhov tsawg tshaj plaws kuj.Raws li cov qauv Q = I²Rt, uas yog, lub zog poob thaum lub sij hawm muab hluav taws xob yog qhov tsawg tshaj plaws, yog li qhov no yog vim li cas cov cable yuav tsum tau siv zoo.Muaj kev nyab xeeb.
Raws li peb tau hais los saum toj no, cov qauv kev poob hluav taws xob, Q = I²Rt, txhawm rau txhawm rau poe fais fab mov kom muaj qhov poob qis tshaj plaws los ntawm PSE fais fab mov kawg mus rau PD lub zog txais khoom, qhov tsawg kawg nkaus tam sim no thiab qhov tsawg kawg nkaus kuj yuav tsum tau ua kom tiav. cov txiaj ntsig zoo tshaj plaws nyob rau hauv tag nrho cov txheej txheem kev siv hluav taws xob.


Post lub sij hawm: Mar-17-2022