Tare da balagagge da haɓaka fasahar SCM a farkon shekarun 80s, kasuwar kayan aikin duniya ta kasance ta asali ta hanyar mitoci masu wayo, wanda aka danganta ga buƙatun bayanan kasuwanci.Ɗaya daga cikin mahimman sharuɗɗan don kamfanoni don zaɓar mita shine samun hanyar sadarwa ta hanyar sadarwa.Fitowar siginar analog na farko shine tsari mai sauƙi, sannan kayan aikin kayan aikin shine RS232 interface, wanda zai iya cimma sadarwa ta aya-zuwa-aya, amma ta wannan hanyar ba za ta iya cimma aikin sadarwar ba, sannan fitowar RS485 ta warware wannan matsala.
RS485 wani ma'auni ne wanda ke bayyana halayen lantarki na direbobi da masu karɓa a cikin daidaitattun tsarin multipoint na dijital.Ƙungiyoyin Masana'antu na Sadarwa da Ƙungiyar Masana'antu ta Lantarki sun ayyana ma'auni.Cibiyoyin sadarwar dijital ta amfani da wannan ma'auni na iya isar da sigina yadda ya kamata a kan nesa mai nisa da kuma cikin yanayin hayaniyar lantarki.RS-485 yana ba da damar daidaita hanyoyin sadarwar gida da kuma hanyoyin sadarwar reshe da yawa.
Saukewa: RS485yana da nau'ikan wayoyi guda biyu na tsarin waya biyu da tsarin waya hudu.Tsarin waya huɗu kawai zai iya cimma yanayin sadarwa aya-zuwa-aya, ba kasafai ake amfani da shi ba.Yanayin tsarin wayoyi guda biyu galibi ana amfani da su tare da tsarin topology na bas kuma ana iya haɗa su da nodes 32 a galibi a cikin bas ɗaya.
A cikin hanyar sadarwar sadarwa ta RS485, ana amfani da babbar hanyar sadarwa ta hanyar sadarwa gabaɗaya, wato, ana haɗa babban mita tare da ƙananan mita masu yawa.A yawancin lokuta, haɗin haɗin sadarwar RS-485 yana haɗawa kawai tare da nau'i-nau'i biyu na murdadden ƙarshen "A" da "B" na kowane mahaɗin, yayin da yin watsi da haɗin ƙasa.Wannan hanyar haɗin kai a lokuta da yawa na iya aiki bisa ga al'ada, amma ta binne babban haɗari na ɓoye.Ɗaya daga cikin dalilan shine kutsewar yanayin gama gari: RS – 485 interface yana ɗaukar hanyar watsa yanayin banbanta kuma baya buƙatar gano siginar akan kowane tunani, amma gano bambancin wutar lantarki tsakanin wayoyi guda biyu, wanda zai iya haifar da jahiltar wutar lantarki ta gama gari. iyaka.RS485 transceiver gama gari irin ƙarfin lantarki tsakanin - 7V da + 12V kuma duk hanyar sadarwa na iya aiki akai-akai, kawai lokacin da ta cika sharuddan da ke sama,;Lokacin da yanayin gama gari na layin hanyar sadarwa ya wuce wannan kewayon, kwanciyar hankali da amincin sadarwa za su yi tasiri, har ma na'urar za ta lalace.Dalili na biyu shine matsalar EMI: yanayin gama gari na siginar fitarwa na direban mai aikawa yana buƙatar hanyar dawowa.Idan babu ƙaramin juriya ta dawowa (sigina ƙasa), za ta koma tushen a cikin nau'i na radiation, kuma dukan bas zai haskaka electromagnetic taguwar ruwa waje kamar wata babbar eriya.
Matsakaicin tsarin sadarwa na yau da kullun shine RS232 da RS485, waɗanda ke ayyana ƙarfin lantarki, impedance, da sauransu, amma ba sa ayyana ka'idar software.Ya bambanta da RS232, RS485 fasali sun haɗa da:
1. Lantarki halaye na RS-485: dabaru "1" ana wakilta da irin ƙarfin lantarki bambanci tsakanin biyu Lines kamar + (2 - 6) V;Ma'ana "0" yana wakilta ta bambancin ƙarfin lantarki tsakanin layukan biyu kamar - (2 - 6) V. Lokacin da matakin siginar keɓancewa ya kasance ƙasa da RS-232-C, ba shi da sauƙi don lalata guntu na kewayawa, kuma matakin ya dace da matakin TTL, don haka ya dace don haɗawa da kewayen TTL.
2. Matsakaicin adadin watsa bayanai na RS-485 shine 10Mbps.
3. RS-485 dubawa yana da ƙarfi, wato, tsangwama mai kyau na hana amo.
4. Matsakaicin nisa watsawa na RS-485 dubawa shine ƙimar daidaitattun ƙafar ƙafa 4000, a zahiri yana iya kaiwa mita 3000 (bayanan ka'idar, a cikin aiki mai amfani, iyakar iyaka shine kawai har zuwa mita 1200), ƙari, RS-232 -C interface kawai yana ba da damar haɗa transceiver 1 akan bas, wato ƙarfin tashar guda ɗaya.An ba da izinin haɗin RS-485 akan bas ɗin don haɗawa har zuwa 128 transceivers.Wato, tare da iyawar tashoshin tashoshi da yawa, masu amfani za su iya amfani da ƙirar RS-485 guda ɗaya don saita hanyar sadarwa na na'urori cikin sauƙi.
Saboda ƙirar RS-485 yana da tsangwama mai kyau na hana surutu, fa'idodin da ke sama na nesa mai nisa da iyawar tashoshi da yawa sun sa ya zama mafi fifikon keɓancewar siriyal.Saboda cibiyar sadarwar rabin-duplex da ta ƙunshi RS485 ke dubawa gabaɗaya tana buƙatar wayoyi biyu kawai, ƙirar RS485 tana ɗaukar watsa nau'ikan murɗaɗɗen garkuwa.Mai haɗin haɗin haɗin RS485 yana amfani da toshe toshe 9-core na DB-9, kuma tashar RS485 mai hankali tana amfani da DB-9 (rami), kuma RS485 mai haɗin maballin madannai yana amfani da DB-9 (alura).
Lokacin aikawa: Maris 15-2021