Abwenzi ambiri afunsa mobwerezabwereza ngati magetsi a PoE ali okhazikika? Ndi chingwe chiti chomwe chili chabwino pamagetsi a PoE? Chifukwa chiyani kamera sikuwonekabe ikayendetsedwa ndi switch ya PoE? Ndi zina zotero, izi zimagwirizana kwenikweni ndi kutayika kwa mphamvu kwa magetsi a POE, omwe amanyalanyaza mosavuta ntchito.
1, Kodi magetsi a POE ndi chiyani
PoE imatanthawuza ukadaulo woperekera magetsi a DC pazigawo zina zozikidwa pa IP (monga mafoni a IP, ma AP, makamera a netiweki, ndi zina zotere) popanda kusintha kwa Ethernet Cat yomwe ilipo. 5 cabling zomangamanga.
Ukadaulo wa PoE utha kuwonetsetsa chitetezo cha ma cabling omwe alipo kale ndikuwonetsetsa kuti maukonde omwe alipo kale akugwira ntchito, kuchepetsa ndalama.
Dongosolo lathunthu la PoE limaphatikizapo magawo awiri: chida chomaliza chamagetsi ndi chida chomaliza cholandirira.
Zida Zopangira Mphamvu (PSE): Ma switch a Ethernet, ma routers, ma hub, kapena zida zina zosinthira maukonde zomwe zimathandizira magwiridwe antchito a POE.
Chipangizo cholandirira mphamvu (PD): Mu dongosolo loyang'anira, makamaka ndi kamera ya netiweki (IPC).
2, POE magetsi muyezo
Muyezo waposachedwa wapadziko lonse wa IEEE802.3bt uli ndi zofunikira ziwiri:
Mtundu woyamba: Mmodzi wa iwo amafunikira PSE kuti akwaniritse mphamvu yotulutsa 60W, ndi mphamvu yofikira pa chipangizo cha 51W (monga momwe tawonetsera pa tebulo pamwambapa, iyi ndi data yotsika kwambiri), ndi kutaya mphamvu kwa 9W.
Njira yachiwiri imafuna kuti PSE ikwaniritse mphamvu yotulutsa 90W, ndi mphamvu ya 71W kufika pa chipangizo cholandira ndi kutaya mphamvu kwa 19W.
Kuchokera pamiyezo yomwe ili pamwambayi, zikhoza kuwoneka kuti pamene mphamvu ikuwonjezeka, kutayika kwa mphamvu sikuli kofanana ndi magetsi, koma kumawonjezeka. Ndiye kodi kutayika kwa PSE kungawerengedwe bwanji muzogwiritsa ntchito?
3, POE mphamvu kotunga kutaya
Choncho tiyeni tione kaye mmene sayansi ya kusukulu ya pulayimale imawerengera kutayika kwa mphamvu ya waya.
Lamulo la Joule ndi lamulo lomwe limafotokoza mochulukira kutembenuka kwa mphamvu yamagetsi kukhala mphamvu yamafuta poyendetsa pakali pano.
Zomwe zili ndi izi: Kutentha komwe kumapangidwa ndi magetsi omwe akudutsa pa kondakitala kumagwirizana ndi mphamvu ya quadratic ya panopa, kukana kwa conductor, ndi nthawi yamagetsi. Ndiko kuti, kugwiritsidwa ntchito kwa ogwira ntchito komwe kumapangidwa panthawi yowerengera.
Lamulo la Joule la masamu: Q=I ² Rt (yogwiritsidwa ntchito kumadera onse), pomwe Q ndi kutaya mphamvu P, ine ndi panopa, R ndi kukana, ndipo t ndi nthawi.
Pogwiritsa ntchito, monga PSE ndi PD zimagwira ntchito nthawi imodzi, kutayika sikudalira nthawi. Chomaliza ndi chakuti mu dongosolo la POE, mphamvu yotayika ya chingwe cha intaneti imagwirizana mwachindunji ndi mphamvu ya quadratic yamakono komanso yofanana ndi kukula kwa kukana. Mwachidule, kuti tichepetse mphamvu yogwiritsira ntchito chingwe cha intaneti, tiyenera kuyesetsa kuchepetsa mphamvu yamakono ya waya ndi kukana kwa chingwe cha intaneti momwe tingathere. Kufunika kochepetsa mphamvu yapano ndikofunikira kwambiri.
Kotero tiyeni tiwone magawo enieni a miyezo yapadziko lonse lapansi:
Muyeso wa IEEE802.3af, kukana kwa chingwe cha netiweki ndi 20 Ω, voteji yofunikira ya PSE ndi 44V, yapano ndi 0.35A, ndi mphamvu yotayika P = 0.35 * 0.35 * 20 = 2.45W.
Momwemonso, mu IEEE802.3at muyezo, kukana kwa chingwe cha netiweki ndi 12.5 Ω, voliyumu yofunikira ndi 50V, pano ndi 0.6A, ndi mphamvu yotayika P = 0.6 * 0.6 * 12.5 = 4.5W.
Palibe vuto kugwiritsa ntchito njira yowerengera iyi pamiyezo yonse iwiri. Koma zikafika pamlingo wa IEEE802.3bt, sungathe kuwerengedwa motere. Ngati magetsi ndi 50V ndipo mphamvu yofikira 60W iyenera kukhala 1.2A panopa, ndiye kuti mphamvu yotayika ndi P = 1.2 * 1.2 * 12.5 = 18W. Kuchotsa kutayika, mphamvu yofikira chipangizo cha PD ndi 42W yokha.
4, Zifukwa za kutaya mphamvu mu POE
Ndiye chifukwa chake ndi chiyani kwenikweni?
Zofunikira zenizeni za 51W zimachepetsedwa ndi 9W yamagetsi amagetsi. Ndiye ndi chiyani chomwe chinayambitsa cholakwika chowerengera.
Zida Zopangira Mphamvu (PSE): Ma switch a Ethernet, ma routers, ma hub, kapena zida zina zosinthira maukonde zomwe zimathandizira magwiridwe antchito a POE.
Chipangizo cholandirira mphamvu (PD): Mu dongosolo loyang'anira, makamaka ndi kamera ya netiweki (IPC).
2, POE magetsi muyezo
Muyezo waposachedwa wapadziko lonse wa IEEE802.3bt uli ndi zofunikira ziwiri:
Mtundu woyamba: Mmodzi wa iwo amafunikira PSE kuti akwaniritse mphamvu yotulutsa 60W, ndi mphamvu yofikira pa chipangizo cha 51W (monga momwe tawonetsera pa tebulo pamwambapa, iyi ndi data yotsika kwambiri), ndi kutaya mphamvu kwa 9W.
Njira yachiwiri imafuna kuti PSE ikwaniritse mphamvu yotulutsa 90W, ndi mphamvu ya 71W kufika pa chipangizo cholandira ndi kutaya mphamvu kwa 19W.
Kuchokera pamiyezo yomwe ili pamwambayi, zikhoza kuwoneka kuti pamene mphamvu ikuwonjezeka, kutayika kwa mphamvu sikuli kofanana ndi magetsi, koma kumawonjezeka. Ndiye kodi kutayika kwa PSE kungawerengedwe bwanji muzogwiritsa ntchito?
3, POE mphamvu kotunga kutaya
Choncho tiyeni tione kaye mmene sayansi ya kusukulu ya pulayimale imawerengera kutayika kwa mphamvu ya waya.
Lamulo la Joule ndi lamulo lomwe limafotokoza mochulukira kutembenuka kwa mphamvu yamagetsi kukhala mphamvu yotentha poyendetsa pano.
Zomwe zili ndi izi: Kutentha komwe kumapangidwa ndi magetsi omwe akudutsa pa kondakitala kumagwirizana ndi mphamvu ya quadratic ya panopa, kukana kwa conductor, ndi nthawi yamagetsi. Ndiko kuti, kugwiritsidwa ntchito kwa ogwira ntchito komwe kumapangidwa panthawi yowerengera.
Lamulo la Joule la masamu: Q=I ² Rt (yogwiritsidwa ntchito kumadera onse), pomwe Q ndi kutaya mphamvu P, ine ndi panopa, R ndi kukana, ndipo t ndi nthawi.
Pogwiritsa ntchito, monga PSE ndi PD zimagwira ntchito nthawi imodzi, kutayika sikudalira nthawi. Chomaliza ndi chakuti mu dongosolo la POE, mphamvu yotayika ya chingwe cha intaneti imagwirizana mwachindunji ndi mphamvu ya quadratic yamakono komanso yofanana ndi kukula kwa kukana. Mwachidule, kuti tichepetse mphamvu yogwiritsira ntchito chingwe cha intaneti, tiyenera kuyesetsa kuchepetsa mphamvu yamakono ya waya ndi kukana kwa chingwe cha intaneti momwe tingathere. Kufunika kochepetsa mphamvu yapano ndikofunikira kwambiri.
Kotero tiyeni tiwone magawo enieni a miyezo yapadziko lonse lapansi:
Muyeso wa IEEE802.3af, kukana kwa chingwe cha netiweki ndi 20 Ω, voteji yofunikira ya PSE ndi 44V, yapano ndi 0.35A, ndi mphamvu yotayika P = 0.35 * 0.35 * 20 = 2.45W.
Momwemonso, mu IEEE802.3at muyezo, kukana kwa chingwe cha netiweki ndi 12.5 Ω, voliyumu yofunikira ndi 50V, pano ndi 0.6A, ndi mphamvu yotayika P = 0.6 * 0.6 * 12.5 = 4.5W.
Palibe vuto kugwiritsa ntchito njira yowerengera iyi pamiyezo yonse iwiri. Koma zikafika pamlingo wa IEEE802.3bt, sungathe kuwerengedwa motere. Ngati magetsi ndi 50V ndipo mphamvu yofikira 60W iyenera kukhala 1.2A panopa, ndiye kuti mphamvu yotayika ndi P = 1.2 * 1.2 * 12.5 = 18W. Kuchotsa kutayika, mphamvu yofikira chipangizo cha PD ndi 42W yokha.
4, Zifukwa za kutaya mphamvu mu POE
Ndiye chifukwa chake ndi chiyani kwenikweni?
Zofunikira zenizeni za 51W zimachepetsedwa ndi 9W yamagetsi amagetsi. Ndiye ndi chiyani chomwe chinayambitsa cholakwika chowerengera.
Zitha kuwoneka kuti chingwe chabwinoko, kukana kocheperako, molingana ndi chilinganizo cha Q = I ² Rt, zomwe zikutanthauza kuti kutayika kwa magetsi panthawi yamagetsi ndikocheperako, ndiye chifukwa chake ndikofunikira kugwiritsa ntchito zingwe. chabwino. Ndikofunikira kugwiritsa ntchito zingwe za Gulu 6 ngati njira yotetezeka.
Monga tafotokozera pamwambapa, njira yotaya mphamvu, Q=I ² Rt, kuti muchepetse kutayika pakati pa malo opangira magetsi a PSE ndi zida zolandirira PD, zocheperako komanso kukana zimafunika kuti zitheke kuchita bwino mu mphamvu zonse. njira yoperekera.
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Nthawi yotumiza: May-30-2023