RS-485, tseem hu ua EIA-485, yog tus qauv kev sib txuas lus raws tu qauv siv rau kev sib kis cov ntaub ntawv hauv kev lag luam thiab kev lag luam. Nws qhia txog cov yam ntxwv hluav taws xob ntawm cov cables thiab cov khoom sib txuas siv hauv RS -485 network.
Thaum teeb tsa RS-485 network, ntau hom cables feem ntau siv. Cov cables no yog tsim los muab kev sib txuas lus zoo thiab suab nrov-tiv thaiv kev sib txuas lus ntev. Ntawm no yog cov hom tseem ceeb ntawm cov cables siv rau RS -485:
Twisted Pair Cable: Twisted khub cables yog hom siv ntau tshaj plaws rau RS-485 tes hauj lwm. Lawv muaj ob lub insulated tooj liab conductors twisted ua ke kom txo tau electromagnetic cuam tshuam (EMI) thiab crosstalk. Qhov nrov tshaj plaws twisted khub cables rau RS-485 yog Qeb 5e (CAT5e) thiab Qeb 6 (CAT6) cables. Cov cables no muaj ntau dua bandwidth thiab muaj peev xwm txhawb nqa cov ntaub ntawv ntau dua nyob rau qhov ntev.
Shielded Twisted Pair (STP) Cable: STP cables zoo ib yam li twisted khub cables tab sis nrog ib txheej hlau thaiv ntxiv. Lub shielding muab kev tiv thaiv zoo dua tiv thaiv sab nraud electromagnetic cuam tshuam, ua STP cables haum rau ib puag ncig uas muaj suab nrov hluav taws xob. STP cables feem ntau yog siv nyob rau hauv kev lag luam chaw uas muaj lub cev muaj zog, cov khoom siv hluav taws xob, lossis lwm qhov chaw ntawm hluav taws xob cuam tshuam.
Unshielded Twisted Pair (UTP) Cable: UTP cables zoo ib yam li STP cables tab sis tsis muaj hlau thaiv. Lawv pheej yig dua thiab yooj yim rau nruab dua STP cables, tab sis lawv muaj kev tiv thaiv tsawg dua EMI. UTP cables yog tsim rau RS-485 networks nyob rau hauv ib puag ncig uas tsis muaj suab nrov los yog thaum lub cable khiav luv luv thiab deb ntawm qhov chaw ntawm kev cuam tshuam.
Multi-Conductor Cable: Qee zaum, ntau tus neeg xyuas pib cables nrog ib tus zuj zus shielded khub lossis quad siv rau RS-485 kev teeb tsa. Cov cables no muaj ntau yam twisted khub los yog quad configurations nyob rau hauv ib tug cable sheath. Lawv muab kev yooj yim thaum txuas ntau yam RS-485 cov khoom siv hauv ib lub cable khiav, txo cov xov tooj ntawm cov cables xav tau thiab ua kom yooj yim rau kev teeb tsa.
Thaum xaiv ib lub cable rau RS-485 network, nws yog ib qho tseem ceeb uas yuav tau xav txog yam xws li qhov kev ncua deb ntawm cov khoom siv, cov ntaub ntawv tus nqi, ib puag ncig, thiab muaj hluav taws xob nrov. Nws tseem ceeb heev uas yuav tau ua raws li cov chaw tsim khoom cov lus pom zoo thiab ua raws li RS-485 tus qauv kom ntseeg tau tias kev sib txuas lus zoo.
Ntxiv nrog rau cov cables, kev txiav tawm kom raug yog qhov tseem ceeb hauv RS-485 tes hauj lwm. Termination resistors tau muab tso rau ntawm ob qho kawg ntawm cable kom txo cov teeb liab kev cuam tshuam thiab ua kom lub teeb pom kev ncaj ncees. Tus nqi ntawm qhov kev txiav tawm cov resistors feem ntau sib xws rau cov yam ntxwv impedance ntawm cable, uas feem ntau yog 120 ohms rau RS -485.
Zuag qhia tag nrho, kev xaiv cov cables rau RS-485 tes hauj lwm yog nyob ntawm cov kev cai tshwj xeeb ntawm kev teeb tsa, thiab cov yam ntxwv xws li kev ncua deb, suab nrov, thiab pob nyiaj siv ua lub luag haujlwm tseem ceeb hauv kev txiav txim siab hom kab hluav taws xob zoo tshaj plaws.
