Abokai da yawa sun yi ta tambaya ko wutar lantarki ta PoE ta tsaya tsayin daka? Wace kebul ɗin ke da kyau don samar da wutar lantarki na PoE? Me yasa har yanzu kamara ba ta nunawa lokacin da PoE ke kunna wutar lantarki? Da sauransu, waɗannan a zahiri suna da alaƙa da asarar wutar lantarki na POE mai samar da wutar lantarki, wanda ke sauƙin mantawa da ayyukan.
1. Menene POE wutar lantarki
PoE yana nufin fasaha na samar da wutar lantarki na DC don wasu tashoshi na tushen IP (kamar wayoyin IP, APs na cibiyar sadarwar gida mara waya, kyamarori na cibiyar sadarwa, da dai sauransu) ba tare da wani gyare-gyare ga Ethernet Cat na yanzu ba. 5 kayan aikin cabling.
Fasahar PoE na iya tabbatar da tsaro na kebul ɗin da aka tsara a yanzu yayin da yake tabbatar da aiki na yau da kullun na cibiyoyin sadarwa, rage farashin.
Cikakken tsarin PoE ya haɗa da sassa biyu: na'urar ƙarewar wutar lantarki da na'ura mai karɓa.
Kayan Kayan Wutar Lantarki (PSE): Maɓallai na Ethernet, masu amfani da hanyar sadarwa, cibiyoyi, ko wasu na'urori masu sauya hanyar sadarwa waɗanda ke goyan bayan ayyukan POE.
Na'urar karɓar wutar lantarki (PD): A cikin tsarin kulawa, galibi kyamarar cibiyar sadarwa ce (IPC).
2. POE samar da wutar lantarki misali
Sabon ma'aunin duniya na IEEE802.3bt yana da buƙatu guda biyu:
Nau'i na farko: Ɗaya daga cikinsu yana buƙatar PSE don cimma ƙarfin fitarwa na 60W, tare da wutar lantarki ya kai ga na'urar karɓa na 51W (kamar yadda aka nuna a cikin tebur a sama, wannan shine mafi ƙarancin bayanai), da asarar wutar lantarki na 9W.
Hanya ta biyu tana buƙatar PSE don cimma ƙarfin fitarwa na 90W, tare da ƙarfin 71W ya isa na'urar karɓa da asarar wutar lantarki na 19W.
Daga ka'idodin da ke sama, ana iya ganin cewa yayin da wutar lantarki ke ƙaruwa, asarar wutar ba ta dace da wutar lantarki ba, sai dai yana ƙaruwa. Don haka ta yaya za a iya ƙididdige asarar PSE a aikace-aikace masu amfani?
3. POE wutar lantarki hasara
Don haka bari mu fara duba yadda ilimin physics na tsakiya ke lissafin asarar wutar lantarki.
Dokokin Joule doka ce da ke bayyana yawan jujjuyawar makamashin lantarki zuwa makamashin thermal ta hanyar gudanar da halin yanzu.
Abin da ke ciki shine: Zafin da ake samu ta hanyar wucewa ta halin yanzu yana daidai da ƙarfin quadratic na halin yanzu, juriya na mai gudanarwa, da lokacin lantarki. Wato, yawan amfani da ma'aikata da aka samar yayin aikin lissafin.
Maganar lissafi na dokar Joule: Q=I ² Rt (wanda ya dace da duk da'irori), inda Q shine asarar wutar lantarki P, Ni ne halin yanzu, R shine juriya, kuma t shine lokacin.
A cikin amfani mai amfani, yayin da PSE da PD ke aiki a lokaci ɗaya, asarar ba ta da lokaci. Ƙarshe shi ne cewa a cikin tsarin POE, asarar wutar lantarki na kebul na cibiyar sadarwa yana daidai da ƙarfin quadratic na yanzu kuma kai tsaye daidai da girman juriya. A taƙaice, don rage yawan wutar lantarki na kebul na cibiyar sadarwa, ya kamata mu yi ƙoƙari mu rage halin yanzu na waya da kuma juriya na hanyar sadarwa kamar yadda zai yiwu. Muhimmancin rage halin yanzu yana da mahimmanci musamman.
Don haka bari mu kalli takamaiman ma'auni na ƙa'idodin ƙasashen duniya:
A cikin ma'auni na IEEE802.3af, juriya na kebul na cibiyar sadarwa shine 20 Ω, ƙarfin fitarwa na PSE da ake buƙata shine 44V, na yanzu shine 0.35A, da ƙarfin asarar P = 0.35 * 0.35 * 20=2.45W.
Hakazalika, a cikin ma'auni na IEEE802.3at, juriya na kebul na cibiyar sadarwa shine 12.5 Ω, ƙarfin da ake buƙata shine 50V, na yanzu shine 0.6A, da kuma asarar ikon P=0.6 * 0.6 * 12.5=4.5W.
Babu matsala ta yin amfani da wannan hanyar lissafi don ma'auni biyu. Amma idan yazo ga ma'aunin IEEE802.3bt, ba za a iya ƙididdige shi kamar haka ba. Idan ƙarfin lantarki shine 50V kuma ƙarfin da zai kai 60W yana buƙatar zama 1.2A na yanzu, to, ƙarfin asarar shine P=1.2 * 1.2 * 12.5=18W. Rage asarar, ikon isa ga na'urar PD shine kawai 42W.
4. Dalilan asarar wutar lantarki a POE
To menene ainihin dalili?
Ana rage ainihin abin da ake buƙata na 51W da 9W na makamashin lantarki. To menene ainihin ya haifar da kuskuren lissafin.
Kayan Kayan Wutar Lantarki (PSE): Maɓallai na Ethernet, masu amfani da hanyar sadarwa, cibiyoyi, ko wasu na'urori masu sauya hanyar sadarwa waɗanda ke goyan bayan ayyukan POE.
Na'urar karɓar wutar lantarki (PD): A cikin tsarin kulawa, galibi kyamarar cibiyar sadarwa ce (IPC).
2. POE samar da wutar lantarki misali
Sabon ma'aunin duniya na IEEE802.3bt yana da buƙatu guda biyu:
Nau'i na farko: Ɗaya daga cikinsu yana buƙatar PSE don cimma ƙarfin fitarwa na 60W, tare da wutar lantarki ya kai ga na'urar karɓa na 51W (kamar yadda aka nuna a cikin tebur a sama, wannan shine mafi ƙarancin bayanai), da asarar wutar lantarki na 9W.
Hanya ta biyu tana buƙatar PSE don cimma ƙarfin fitarwa na 90W, tare da ƙarfin 71W ya isa na'urar karɓa da asarar wutar lantarki na 19W.
Daga ka'idodin da ke sama, ana iya ganin cewa yayin da wutar lantarki ke ƙaruwa, asarar wutar ba ta dace da wutar lantarki ba, sai dai yana ƙaruwa. Don haka ta yaya za a iya ƙididdige asarar PSE a aikace-aikace masu amfani?
3. POE wutar lantarki hasara
Don haka bari mu fara duba yadda ilimin physics na tsakiya ke lissafin asarar wutar lantarki.
Dokokin Joule doka ce da ke bayyana yawan jujjuyawar makamashin lantarki zuwa makamashin thermal ta hanyar gudanar da halin yanzu.
Abin da ke ciki shine: Zafin da ake samu ta hanyar wucewa ta halin yanzu yana daidai da ƙarfin quadratic na halin yanzu, juriya na mai gudanarwa, da lokacin lantarki. Wato, yawan amfani da ma'aikata da aka samar yayin aikin lissafin.
Maganar lissafi na dokar Joule: Q=I ² Rt (wanda ya dace da duk da'irori), inda Q shine asarar wutar lantarki P, Ni ne halin yanzu, R shine juriya, kuma t shine lokacin.
A cikin amfani mai amfani, yayin da PSE da PD ke aiki a lokaci ɗaya, asarar ba ta da lokaci. Ƙarshe shi ne cewa a cikin tsarin POE, asarar wutar lantarki na kebul na cibiyar sadarwa yana daidai da ƙarfin quadratic na yanzu kuma kai tsaye daidai da girman juriya. A taƙaice, don rage yawan wutar lantarki na kebul na cibiyar sadarwa, ya kamata mu yi ƙoƙari mu rage halin yanzu na waya da kuma juriya na hanyar sadarwa kamar yadda zai yiwu. Muhimmancin rage halin yanzu yana da mahimmanci musamman.
Don haka bari mu kalli takamaiman ma'auni na ƙa'idodin ƙasashen duniya:
A cikin ma'auni na IEEE802.3af, juriya na kebul na cibiyar sadarwa shine 20 Ω, ƙarfin fitarwa na PSE da ake buƙata shine 44V, na yanzu shine 0.35A, da ƙarfin asarar P = 0.35 * 0.35 * 20=2.45W.
Hakazalika, a cikin ma'auni na IEEE802.3at, juriya na kebul na cibiyar sadarwa shine 12.5 Ω, ƙarfin da ake buƙata shine 50V, na yanzu shine 0.6A, da kuma asarar ikon P=0.6 * 0.6 * 12.5=4.5W.
Babu matsala ta yin amfani da wannan hanyar lissafi don ma'auni biyu. Amma idan yazo ga ma'aunin IEEE802.3bt, ba za a iya ƙididdige shi kamar haka ba. Idan ƙarfin lantarki shine 50V kuma ƙarfin da zai kai 60W yana buƙatar zama 1.2A na yanzu, to, ƙarfin asarar shine P=1.2 * 1.2 * 12.5=18W. Rage asarar, ikon isa ga na'urar PD shine kawai 42W.
4. Dalilan asarar wutar lantarki a POE
To menene ainihin dalili?
Ana rage ainihin abin da ake buƙata na 51W da 9W na makamashin lantarki. To menene ainihin ya haifar da kuskuren lissafin.
Ana iya ganin cewa mafi kyawun kebul, mafi ƙarancin juriya, bisa ga ma'auni Q = I ² Rt, wanda ke nufin cewa asarar wutar lantarki yayin aikin samar da wutar lantarki shine mafi ƙarancin, don haka wannan shine dalilin da ya sa ya zama dole don amfani da igiyoyi. da kyau. Ana ba da shawarar yin amfani da igiyoyi na Category 6 azaman zaɓi mafi aminci.
Kamar yadda muka ambata a sama, da dabarar wutar lantarki, Q = I ² Rt, don rage girman hasara tsakanin tashar wutar lantarki ta PSE da kayan aiki na PD, ana buƙatar mafi ƙarancin halin yanzu da juriya don cimma mafi kyawun aiki a cikin dukan ikon. tsarin samar da kayayyaki.
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Lokacin aikawa: Mayu-30-2023