Abahlobo abaninzi baye babuza ngokuphindaphindiweyo ukuba umbane we-PoE uzinzile? Yeyiphi intambo elungileyo kubonelelo lwamandla lwe-PoE? Kutheni le nto ikhamera ingabonisi xa inikwe amandla yiPoE switch? Kwaye njalo-njalo, ezi zihambelana nokulahlekelwa kwamandla ombane we-POE, ongenakuhoywa ngokulula kwiiprojekthi.
1, Yintoni unikezelo lwamandla lwePOE
I-PoE ibhekisela kubuchwepheshe bokubonelela ngombane we-DC kwezinye iitheminali ezisekelwe kwi-IP (ezifana neefowuni ze-IP, i-wireless area network access point APs, iikhamera zenethiwekhi, njl. Iziseko ezi-5 zeekhebhile.
Itekhnoloji ye-PoE inokuqinisekisa ukhuseleko lwe-cabling ekhoyo ecwangcisiweyo ngelixa iqinisekisa ukusebenza okuqhelekileyo kothungelwano olukhoyo, ukunciphisa iindleko.
Inkqubo ye-PoE epheleleyo ibandakanya iinxalenye ezimbini: isixhobo sokuphela konikezelo lwamandla kunye nesixhobo sokugqibela sokufumana.
Izixhobo zokubonelela ngombane (PSE): Ukutshintsha kwe-Ethernet, iirotha, ii-hubs, okanye ezinye izixhobo zokutshintsha inethiwekhi ezixhasa ukusebenza kwe-POE.
Isixhobo sokufumana amandla (PD): Kwinkqubo yokubeka iliso, ikakhulu ikhamera yenethiwekhi (IPC).
2, POE umgangatho wonikezelo lwamandla
Umgangatho wamva nje wehlabathi IEEE802.3bt uneemfuno ezimbini:
Uhlobo lokuqala: Omnye wabo ufuna i-PSE ukufezekisa amandla okuvelisa i-60W, kunye namandla afikelela kwisixhobo sokufumana i-51W (njengoko kuboniswe kwitheyibhile engentla, le yidatha ephantsi kakhulu), kunye nokulahlekelwa kwamandla e-9W.
Indlela yesibini idinga i-PSE ukufezekisa amandla okuphuma kwe-90W, kunye namandla e-71W ukufikelela kwisixhobo esifumanayo kunye nokulahlekelwa kwamandla kwe-19W.
Ukususela kule migangatho ingentla, kunokubonwa ukuba njengoko ukunikezelwa kwamandla kwanda, ukulahlekelwa kwamandla akuhambelani nokunikezelwa kwamandla, kodwa kunoko kuyanda. Ke ingaba ilahleko ye-PSE ingabalwa njani kwizicelo ezibonakalayo?
3, POE ilahleko unikezelo lwamandla
Ke masiqale sijonge indlela ifiziksi yesikolo esiphakathi ibala ngayo ilahleko yamandla ocingo.
Umthetho kaJoule ngumthetho ochaza ngokobungakanani ukuguqulwa kwamandla ombane kumandla obushushu ngokuqhuba okwangoku.
Umxholo ngulo: Ubushushu obuveliswa ngumbane odlulayo kwi-conductor buhambelana namandla e-quadratic yangoku, ukuchasana komqhubi, kunye nexesha lokufakelwa kombane. Oko kukuthi, ukusetyenziswa kwabasebenzi okwenziwe ngexesha lenkqubo yokubala.
Umthetho weJoule's law mathematical expression: Q=I ² Rt (isebenza kuzo zonke iisekethe), apho u-Q yilahleko yamandla engu-P, mna ndingowangoku, R luxhathiso, kunye no-t lixesha.
Ukusetyenziswa okusebenzayo, njengoko i-PSE kunye nePD zisebenza ngaxeshanye, ilahleko izimele ngexesha. Isiphetho kukuba kwinkqubo ye-POE, amandla okulahlekelwa kwentambo yenethiwekhi ahambelana ngokuthe ngqo kumandla we-quadratic yangoku kwaye ngokuthe ngqo ngokulingana nobukhulu bokumelana. Ukubeka nje, ukuze kuncitshiswe ukusetyenziswa kwamandla kwentambo yenethiwekhi, kufuneka sizame ukunciphisa i-current ye-wire kunye nokuchasana kwentambo yenethiwekhi kangangoko kunokwenzeka. Ukubaluleka kokunciphisa umsinga kubaluleke kakhulu.
Ngoko ke makhe sijonge iiparameters ezithile zemigangatho yamazwe ngamazwe:
Kwinqanaba le-IEEE802.3af, ukuchasana kwentambo yenethiwekhi yi-20 Ω, i-voltage efunekayo ye-PSE ye-voltage yi-44V, okwangoku yi-0.35A, kunye nokulahlekelwa kwamandla P = 0.35 * 0.35 * 20 = 2.45W.
Ngokufanayo, kwinqanaba le-IEEE802.3, ukuchasana kwentambo yenethiwekhi yi-12.5 Ω, i-voltage efunekayo yi-50V, okwangoku ngu-0.6A, kunye nokulahlekelwa kwamandla P = 0.6 * 0.6 * 12.5 = 4.5W.
Akukho ngxaki ngokusebenzisa le ndlela yokubala kuyo yomibini imigangatho. Kodwa xa kuziwa kumgangatho we-IEEE802.3bt, ayinakubalwa ngolu hlobo. Ukuba i-voltage i-50V kwaye amandla okufikelela kwi-60W kufuneka abe yi-1.2A yangoku, ngoko amandla okulahlekelwa yi-P = 1.2 * 1.2 * 12.5 = 18W. Ukususa ilahleko, amandla okufikelela kwisixhobo sePD yi-42W kuphela.
I-4, Izizathu zokulahlekelwa kwamandla kwi-POE
Ngoko yintoni kanye kanye isizathu?
Eyona mfuno ye-51W icuthwe yi-9W yamandla ombane. Ke yintoni kanye kanye ebangele impazamo yokubala.
Izixhobo zokubonelela ngombane (PSE): Ukutshintsha kwe-Ethernet, iirotha, ii-hubs, okanye ezinye izixhobo zokutshintsha inethiwekhi ezixhasa ukusebenza kwe-POE.
Isixhobo sokufumana amandla (PD): Kwinkqubo yokubeka iliso, ikakhulu ikhamera yenethiwekhi (IPC).
2, POE umgangatho wonikezelo lwamandla
Umgangatho wamva nje wehlabathi IEEE802.3bt uneemfuno ezimbini:
Uhlobo lokuqala: Omnye wabo ufuna i-PSE ukufezekisa amandla okuvelisa i-60W, kunye namandla afikelela kwisixhobo sokufumana i-51W (njengoko kuboniswe kwitheyibhile engentla, le yidatha ephantsi kakhulu), kunye nokulahlekelwa kwamandla e-9W.
Indlela yesibini idinga i-PSE ukufezekisa amandla okuphuma kwe-90W, kunye namandla e-71W ukufikelela kwisixhobo esifumanayo kunye nokulahlekelwa kwamandla kwe-19W.
Ukususela kule migangatho ingentla, kunokubonwa ukuba njengoko ukunikezelwa kwamandla kwanda, ukulahlekelwa kwamandla akuhambelani nokunikezelwa kwamandla, kodwa kunoko kuyanda. Ke ingaba ilahleko ye-PSE ingabalwa njani kwizicelo ezibonakalayo?
3, POE ilahleko unikezelo lwamandla
Ke masiqale sijonge indlela ifiziksi yesikolo esiphakathi ibala ngayo ilahleko yamandla ocingo.
Umthetho kaJoule ngumthetho ochaza ngokobungakanani ukuguqulwa kwamandla ombane kumandla obushushu ngokuqhuba okwangoku.
Umxholo ngulo: Ubushushu obuveliswa ngumbane odlulayo kwi-conductor buhambelana namandla e-quadratic yangoku, ukuchasana komqhubi, kunye nexesha lokufakelwa kombane. Oko kukuthi, ukusetyenziswa kwabasebenzi okwenziwe ngexesha lenkqubo yokubala.
Umthetho weJoule's law mathematical expression: Q=I ² Rt (isebenza kuzo zonke iisekethe), apho u-Q yilahleko yamandla engu-P, mna ndingowangoku, R luxhathiso, kunye no-t lixesha.
Ukusetyenziswa okusebenzayo, njengoko i-PSE kunye nePD zisebenza ngaxeshanye, ilahleko izimele ngexesha. Isiphetho kukuba kwinkqubo ye-POE, amandla okulahlekelwa kwentambo yenethiwekhi ahambelana ngokuthe ngqo kumandla we-quadratic yangoku kwaye ngokuthe ngqo ngokulingana nobukhulu bokumelana. Ukubeka nje, ukuze kuncitshiswe ukusetyenziswa kwamandla kwentambo yenethiwekhi, kufuneka sizame ukunciphisa i-current ye-wire kunye nokuchasana kwentambo yenethiwekhi kangangoko kunokwenzeka. Ukubaluleka kokunciphisa umsinga kubaluleke kakhulu.
Ngoko ke makhe sijonge iiparameters ezithile zemigangatho yamazwe ngamazwe:
Kwinqanaba le-IEEE802.3af, ukuchasana kwentambo yenethiwekhi yi-20 Ω, i-voltage efunekayo ye-PSE ye-voltage yi-44V, okwangoku yi-0.35A, kunye nokulahlekelwa kwamandla P = 0.35 * 0.35 * 20 = 2.45W.
Ngokufanayo, kwinqanaba le-IEEE802.3, ukuchasana kwentambo yenethiwekhi yi-12.5 Ω, i-voltage efunekayo yi-50V, okwangoku ngu-0.6A, kunye nokulahlekelwa kwamandla P = 0.6 * 0.6 * 12.5 = 4.5W.
Akukho ngxaki ngokusebenzisa le ndlela yokubala kuyo yomibini imigangatho. Kodwa xa kuziwa kumgangatho we-IEEE802.3bt, ayinakubalwa ngolu hlobo. Ukuba i-voltage i-50V kwaye amandla okufikelela kwi-60W kufuneka abe yi-1.2A yangoku, ngoko amandla okulahlekelwa yi-P = 1.2 * 1.2 * 12.5 = 18W. Ukususa ilahleko, amandla okufikelela kwisixhobo sePD yi-42W kuphela.
I-4, Izizathu zokulahlekelwa kwamandla kwi-POE
Ngoko yintoni kanye kanye isizathu?
Eyona mfuno ye-51W icuthwe yi-9W yamandla ombane. Ke yintoni kanye kanye ebangele impazamo yokubala.
Inokubonwa ukuba ngcono intambo, incinci ukuchasana, ngokwefomula Q=I ² Rt, okuthetha ukuba ilahleko yamandla ngexesha lenkqubo yonikezelo lombane incinci, kungoko kuyimfuneko ukusebenzisa iintambo. kakuhle. Kucetyiswa ukuba usebenzise iintambo zodidi 6 njengendlela ekhuselekileyo.
Njengoko sikhankanyile ngasentla, ilahleko yefomula yamandla, Q=I ² Rt, ukuze kuncitshiswe ilahleko phakathi kwetheminali yobonelelo lwamandla ePSE kunye nePD efumana izixhobo, ubuncinci bangoku kunye noxhathiso luyafuneka ukuze kuphunyezwe ukusebenza kakuhle kuwo wonke amandla. inkqubo yokubonelela.
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Ixesha lokuposa: May-30-2023