He aha te kawa RS485/ModBus-RTU?

Ko te atanga whakawhitiwhiti RS485 he paerewa e whakamahia whānuitia ana i roto i te mara oahumahime ngā hikohiko arumoni mō te whakawhitiwhiti raupapa. I whakawhanakehia hei whakatika i ngā herenga o ngā paerewa whakawhitiwhiti raupapa o mua, ā, hei whakahohe i te tuku raraunga pono i ngā tawhiti roa me ngā taiao uaua ake.

• Tohu Hiko
  • Ka whakamahia e te RS485 te tohu rerekētanga. Engari ko te waea kotahi hei tuku raraunga pērā i ētahi atu atanga raupapa (pērā i te RS232), e rua ngā waea, ko te tikanga he A me te B te tohu. Ko te rerekētanga ngaohiko i waenga i ēnei waea e rua e tohu ana i ngā raraunga. Ko te rerekētanga ngaohiko pai i waenga i te waea A me te waea B (hei tauira, A – B > 0.2 V) e tautuhia ana he arorau 1, ko te rerekētanga ngaohiko kino (A – B < – 0.2 V) e tohu ana i te arorau 0. He tino pai te ārai haruru o tēnei tikanga tohu rerekētanga. I roto i ngā taiao ahumahi haruru, he mea noa te pokanoa hiko, he iti ake te tūponotanga o te rerekētanga ngaohiko i waenga i ngā waea e rua kia pāngia e te haruru o waho ki te whakataurite ki tētahi pūnaha tohu kotahi-mutunga.
• Te Āheinga Maha-Maka
  • Ko tētahi o ngā āhuatanga tino nui o te RS485 ko tana mahi maha-taka. Ka taea e te pahi RS485 kotahi te tautoko i te 32 ngā pūnga (pūrere). Ka taea e ētahi transceiver RS485 matatau te whakahaere i ngā pūnga maha atu, tae atu ki te 256 i ētahi wā. Mā tēnei ka taea te hono i ngā taputapu maha, pērā i ngā pūoko, ngā actuators, me ngā kaiwhakahaere, ki te pahi whakawhitiwhiti kōrero kotahi. Hei tauira, i roto i te pūnaha aunoatanga whare, ka taea te hono i ngā pūoko pāmahana maha, ngā pūoko haumākū, me ngā kaiwhakahaere rama ki te pahi RS485 kotahi, ka whakaiti i te uaua o te taura me te hoahoa pūnaha.
• Tawhiti Tuku
  • RS485ka taea te whakatutuki i ngā tawhiti tuku roa. I roto i ngā āhuatanga tino pai, me te tere raraunga tae atu ki te 9600 bps, ka taea e ia te tuku raraunga i ngā tawhiti tae atu ki te 1200 mita. I te pikinga o te tere raraunga, ka heke te tawhiti tuku mōrahi. Hei tauira, i te tere raraunga o te 1 Mbps, ko te tawhiti mōrahi he tata ki te 100 mita. Nā tēnei āheinga tawhiti-roa e pai ai mō ngā tono kei reira ngā taputapu e horahia ana i runga i te rohe nui, pērā i roto i ngā tipu ahumahi, ngā whatunga atamai, me ngā pūnaha haumarutanga.

• Mahi Haurua-Taurua
  • Ko te RS485 he atanga whakawhitiwhiti kōrero haurua-rua. Ko te tikanga tēnei ka taea te tuku raraunga i ngā taha e rua, engari kāore i te wā kotahi. Kotahi anake te taputapu i runga i te pahi ka taea te tuku raraunga i te wā kotahi, ko ētahi atu taputapu kei roto i te aratau whiwhi. Hei whakahaere i tēnei, me whai tikanga hei whakahaere ko tēhea taputapu kei a ia te mana ki te tuku. He maha ngā wā ka tutukihia tēnei mā te kawa e tohaina ai ngā wāhitau ki ngā taputapu. Hei tauira, i roto i te kawa Modbus RTU (Remote Terminal Unit), e whakamahia whānuitia ana me te RS485, ka uiui te taputapu matua i ngā taputapu pononga mā te tuku tono me te wāhitau motuhake o te pononga ūnga. Kātahi ka whakautu te pononga kua wāhitauhia, ā, i tēnei wā, ka noho tonu ētahi atu taputapu ki te aratau whiwhi.
• Hototahitanga o te Kawa
  • RS485Ehara i te kawa i a ia anō engari e whakarato ana i te paparanga ā-tinana mō ngā kawa whakawhitiwhiti kōrero. Haunga a Modbus RTU, ko ētahi atu kawa pēnei i a Profibus – DP (Process Field Bus – Decentralized Periphery) e whakamahi ana hoki i te RS485 hei atanga ā-tinana. Ka tautuhia e ēnei kawa te āhua o te anga raraunga, te aro turuki, me te tirotiro hapa. Hei tauira, ka whakamahia e Modbus RTU he hōputu anga roa pumau me ngā moka tīmatanga me te mutu, ā, kei roto ko te waehere tirotiro tauutuutu porowhita (CRC) i te mutunga o ia anga hei kite i ngā hapa tuku. Nā tēnei hototahi ki ngā kawa maha ka tino whai hua te RS485, ā, ka taea te whakamahi i roto i ngā pūnaha ahumahi me ngā pūnaha arumoni rerekē.

• Aunoatanga Ahumahi
  • I roto i ngā taiao ahumahi, ka whakamahia te RS485 hei hono i ngā pūmana arorau ka taea te whakarite (PLC), ngā atanga tangata-mīhini (HMI), ngā pūoko, me ngā kaiwhakaoho. Hei tauira, i roto i tētahi wheketere hanga, ka taea e ngā PLC te kōrero ki ngā pūoko maha (pērā i ngā pūoko tata, ngā pūoko pēhanga) me ngā kaiwhakaoho (pērā i ngā motuka, ngā takirere) mā te whatunga RS485. Mā tēnei ka taea te whakahaere me te aroturuki pokapū i te tukanga whakaputa, kia pai ai te mahi me te urupare tere ki ngā huringa, ki ngā hapa rānei.
• Ngā Pūnaha Whakahaere Whare
  • He mahi nui tā te RS485 i roto i ngā pūnaha whakahaere whare. E whakamahia ana hei hono i ngā taputapu aunoa whare rerekē, pērā i ngā pūnaha whakamahana, whakapūhau, me te hauhautanga (HVAC), ngā pūnaha whakahaere rama, me ngā pūnaha haumarutanga. Hei tauira, ka taea e te kaiwhakahaere whakahaere whare matua te kōrero ki ngā waeine HVAC maha mā te RS485 hei whakarite i te pāmahana, te haumākū, me ngā tautuhinga rere hau kia rite ki te nohoanga o te whare me ngā āhuatanga taiao.
• Whakahaere Pūngao me te Whatunga Atamai
  • I roto i te horopaki o ngā whatunga atamai, ka whakamahia te RS485 hei hono i ngā mita atamai, ngā taputapu aroturuki pūngao, me ngā taputapu tohatoha hiko. Ka taea e ngā mita atamai te tuku raraunga whakapaunga hiko ki tētahi pūwāhi kohikohi raraunga matua mā te RS485. Kātahi ka whakamahia ēnei raraunga mō te utu, te whakahaere kawenga, me te arotau whatunga. Hei tāpiri, ka taea te whakamahi i te RS485 hei whakahaere me te aroturuki i ngā taputapu whakatika ira-mana me ētahi atu taputapu i roto i te whatunga tohatoha hiko.