RS-485 uqhagamshelwano kunye nolawulo

RS-485 yi umgangatho eyaye yamkelwa kuqala kwi Industries Electronic Association. Ukuza kuthi ga ngoku, le ujongene esezantsi nge iimpawu zombane zonke iintlobo balwamkele kunye zidlulisele esetyenziswa ezahlukeneyo kweenkqubo digital elungeleleneyo.

Yintoni na?

Phakathi iingcali RS-485 ligama olude ithandwayo interface, nto leyo ngokubanzi kusetyenziswa kwiinkqubo ezahlukeneyo inkqubo yolawulo mveliso loqhakamshelwano izilawuli ezininzi kwakunye iintlobo nezinye izixhobo phakathi kwabo. Umahluko omkhulu phakathi ujongano abancinane eqhelekileyo RS-232 kukuba ubonelela manyano ngexesha elifanayo iintlobo ezininzi izixhobo.

Ukusebenzisa RS-485 inikwa ngumntu-high speed nokutshintshiselana ngengcaciso phakathi izixhobo ezininzi ngokusebenzisa enye-wire unxibelelwano ikhonkco phakathi-kabini indlela. Isetyenziswa ngokubanzi kushishino mihla kule nkqubo PCS.

Ibanga nesantya

Kusetyenziswa lo mgangatho iyazalisekiswa losasazo iinkcukacha ngesantya ukuya ku-10 Mbit / s, lo gama uluhlu liphezulu liya kuxhomekeka ngqo kwi isantya apho data kudluliselwa. Ngoko ke, ukuqinisekisa ukuba idatha santya siphezulu enokusasazwa ayikho ngaphezulu kwe-120 m, lo gama ngesantya ka 100 kbit / s ulwazi lwencwadi lisasazwa eemitha ngaphezulu kwama-1200.

Inombolo isixhobo yokudibanisa

Inani kwezinto oludibanisa RS-485 ophezulu iya kuxhomekeka ngqo kwi transceiver yintoni isixhobo iyasetyenziswa. samaza ngasinye yenzelwe ukulungiselela ulawulo ngaxeshanye 32 ngu balwamkele umgamgatho, kodwa kufuneka kuqondwe ukuba kukho balwamkele, le ukuvimba igalelo yi-50%, 25% okanye inxalenye kakhulu asemgangathweni, yaye kwimeko lokusebenzisa izixhobo inani elipheleleyo wamacebo kwandisa ngokufanelekileyo.

Izihlanganisi neminqophiso

RS-485 cable akasayi mgangathweni naziphi izakhelo Ifomathi yeengcombolo ezithile okanye protocol. Kwiimeko ezininzi ngcono i data ezisetyenziswayo ngqo lezakhelo efanayo, esebenzisa RS-232, ngamanye badinga data, ukuqala kwaye uyeke amasuntswana, kunye amasuntswana zixatyiswe, xa kukho imfuneko.

Izivumelwano zonxibelelwano basebenza ezininzi iinkqubo zale mihla yenziwa kwi "inkosi-khoboka", oko kukuthi, ezinye uhlobo device kwi-network ehamba phambili kwaye inikwe isicelo sisananelo ngokuthumela inyathelo phakathi zonke izixhobo ikhoboka bahluka iidilesi ubhalo. Le protocol ithandwa kakhulu kuba namhlanje Modbus RT.

Kubalulekile ukuphawula ukuba RS-485 USB naye uhlobo ethile elithile izihlanganisi okanye soldered, oko kukuthi, kunokuthi kwenzeke izihlanganisi kwesibambi, le DB9 kunye nabanye.

uqhagamshelo

Amaninzi, usebenzisa le ujongano idibana kumnatha womsebenzi wobulali, okuhlanganisa transceiver ezininzi.

Ekwenzeni RS-485 uxhulumaniso, kufuneka ukudibanisa ngobuchule kunye namanye iisekethe umqondiso, lidla ngokubizwa ngokuba A no-B Kulo mzekelo, ukuguqulwa akunjalo eyoyikekayo, izixhobo ezinxulumene ngeke isebenze.

amacebo aluncedo

Usebenzisa RS-485 interface, kufuneka uthathe ingqalelo iinkalo eziliqela yomsebenzi wakhe;

• Imeko kakhulu kangangoko ukugqithisa uphawu - yinto Intambo kwisibini, ephothiweyo.
• Intambo ziphile ngokuyimfuneko kufuneka singaliva ngoncedo resistors olulodwa terminal.
• Network, esebenzisa umgangatho okanye USB RS-485, kufuneka wenze ngaphandle amasebe ibhasi yethopholoji efanayo.
• Ezi zixhobo kufuneka adityaniswe kwi ngcingo cable mfutshane kangangoko.

Kulo mzekelo, simse ukuze ngolo RS-485 yekhompyutha, - i sibini ecikizekileyo, ephothiweyo, njengoko iyahluka radiation uphawu kancinane olwaye lwamfimfitha, kwaye ukhuselo elungileyo kakhulu ukuphazamiseka. Ukuba izixhobo iya kusebenza phantsi ingxolo ephezulu kakhulu lwangaphandle, kubhetele ukusebenzisa intambo, wasikhusela sibini, ephothiweyo, idityaniswe emhlabeni olukhuselayo kunye ikhaka intambo.

isivumelwano

Ngokusebenzisa terminal resistors standard okanye USB RS-485 ibonelela ulungelelwaniso olupheleleyo ekupheleni open lomgca cable le ilandelwa ngokususa ngokupheleleyo ithuba umqondiso vangama.

resistors ukumelana mgangatho ukuvimba olufanelekileyo uphawu intambo kunye nabo iintambo edityanisiweyo esusela kwi ecikizekileyo, ephothiweyo-isibini USB, kwiimeko ezininzi, ukuba kusilungele, nama-100-120 ohms. Umzekelo, ngeranti ezithandwayo namhlanje UTP-5 USB, lisetyenziswa kwinkqubo ngokubekwa Ethernet na ukuba ukuvimba uphawu ohms 100. Kuba kwezinye iindlela intambo zingasetyenziswa kunye naliphi na ihlelo.

Resistors, ukuba kuyimfuneko, kunokwenziwa natywinwa kwi izikhonkwane USB sele isixhobo lokugqibela. Ayifane resistors zifakwa kwifowni, ukuze ukuba udibaniso lwe resistor kuyimfuneko ukufaka ame. Kulo mzekelo, ukuba kwenziwe ngaphandle isixhobo ngokupheleleyo umgca rassoglasovyvaetsya. Kwaye ukuze kuqinisekiswe ukusebenza eqhelekileyo yonke le nkqubo, kufuneka ukudibanisa ikepusi elifanayo.

amazinga uphawu

RS-485 isebenzisa losasazo data wesiphaluka elungeleleneyo, oko kukuthi, amazinga ombane kule migca umqondiso A no-B iya ziyahluka inkcaso.

Esebenzisa woluvo kufuneka zinikwe kwinqanaba umqondiso 1.5 wokuwalayisha ngokupheleleyo, yaye kungekho ngaphezulu kwama-6 kwimeko xa ifowuni esigangeni. Inqanaba ombane ulinganiswa differentially xa kuthelekiswa kwabanye umgca imiqondiso nganye.

Apho umdlali esezantsi wafumana kwinqanaba uphawu kuyo nayiphi na imeko kufuneka ibe kumgangatho hayi ngaphantsi kwe 200 MV.

ukufuduka

Kwimeko apho kungekho uphawu kule migca umqondiso, kancane ukulinganisa kwenzeka, apho ufumana ukhuseleko receiver nxamnye positives bobuxoki.

Iingcali Siyaleza ukwenza ukulinganisa lilikhulu kancinci nje 200 MV, ekubeni eli xabiso nto elihambelana unreliability zone uphawu igalelo eqhelekileyo. Kulo mzekelo, kwikhonkco A enziwe isilo kwipali ezintle umthombo, lo gama i-chain B enziwe isilo eqhelekileyo.

umzekelo

Ukungqinelana ukubana ezifunwayo kunye ukubalwa ombane umbane lwenziwa amahlelo resistors. Umzekelo, ukuba oko kuyimfuneko ukuze ufumane lisisiqalo kwi 250 MV usebenzisa resistors yesiphelo R _T = 120 ohms ukuba umthombo unalo amandla ombane ayi-12 V. Ukususela kule meko resistors ezimbini anxulumene ngokunxuseneyo omnye komnye yaye ngokupheleleyo alisayi kuwathathela ngqalelo umthwalo kwicala receiver ke, ucalucalulo ngoku 0,0042 a, ngelixa uxhathiso lilonke beesekethe icala yi 2857 ohms. R _ukubona kule meko iza kuba malunga 1400 ohms, ngoko kufuneka ukhethe kwimvaba ethile elikufutshane.

Umzekelo bekuya kuba 1.5 kohm resistor iyasetyenziswa, eyenzelwe ukubana, kwakunye resistor lwangaphandle ukuya volts-12. Ukongeza, xa kwimveliso yethu yangoku inkqubo isilawuli decoupled unikezelo lwamandla, olilungu awayeqhuba imixokelelwane ingxenye.

Kakade ke, zikho nezinye embodiments ezininzi icala ezisebenzisa RS-485 Converter kanye nezinye izinto kodwa nayiphi na imeko, ezi ukuphunyezwa iziphaluka lungiselelo imbaxa, oko kuyimfuneko ukuze bakuthathele ingqalelo into yokuba isiza, nto leyo eza kunika oko, iya kuba njalo zivaliwe phantsi okanye bade bagqibele it ngokupheleleyo asuswe kwi network.

Ukuba kukho ukulinganisa, ngoko ke wesekethe amandla A on idle ngokupheleleyo ngu dibanisa ngokumalunga beesekethe B, nto leyo incopho yothelekiso xa isixhobo esitsha liqhagamshelwe kwiingcingo USB ngaphandle zokuphawula.

kweentambo angachananga ukungathembeki

Ukwenza izindululo ngasentla luvumela yokudluliswa okuqhelekileyo amaza zombane amanqaku ezahlukeneyo womnatha, ukuba kusetyenziswa isiseko RS-485 protocol. Ukuba akukho uzaliseka ubuncinane ezinye iimfuno ziya kuvela Bill. Kwezithintelo kakhulu ephawuleka kuqala ukuvela kwi mzekelo, ukuba isantya datha ngaphezulu kwe-1 Mbit / s, kodwa eneneni, nkqu kwimeko ngesantya osezantsi ayikhuthazwa tu into yokuba ngoyaba ezi zincomo, kwanokuba xa olu thungelwano 'imisebenzi nje emihle. "

Indlela kwiprogram?

Ngexesha lwenkqubo, iindidi izicelo ezisebenza izixhobo usebenzisa yokuchaka RS-485 okanye ezinye izixhobo nale interface, kufuneka ucinge iingongoma ezibalulekileyo. Nazi ke:

• Phambi kokuba uqale uthumela umba, kufuneka ukusebenzisa ngokuyimfuneko sixhobo. Nangona into yokuba, ngokutsho kwimithombo ethile, abuyiselwe ukuze kwenzeka ngokukhawuleza emva ukuvula, ezinye iingcali bacebisa nqumama okokuqala, nto leyo ngexesha iya kulingana izinga isakhelo esinye. Kulo mzekelo, ulwamkelo oluchanekileyo ngexesha yenkqubo ukuchonga ngokupheleleyo iimpazamo ezidlulayo, undikhuphele ngaphandle inkqubo ukuzinza ukulungiselela ulwamkelo data olulandelayo.
• Emva kokuba byte yokugqibela data sikhutshiwe, kucetyiswa ukuba umvumele phambi zokuqhawula isixhobo RS-485. Ngokukodwa, oku kungenxa yokuba iirejista eli uthotho lezibuko rhoqo ngaxeshanye langoku ezimbini, owokuqala apho ome oku owongozelelweyo senzelwe ufumana idata, ngoxa shift imveliso yesibini isetyenziselwa kwaye yesiphumo serial. Nawuphi na umlawuli transmission sophazamiso abunjwe kwimeko kwerejista igalelo imbuqo ingcaciso sele inikwe kwirejista shift, kodwa okwangoku zikhutshiwe. Kungenxa yesi sizathu ukuba emva zosasazo uphazamiseka, kuyimfuneko ukuba asekele unqumamo ethile phambi kokuba zokuqhawula samaza, leyo kufuneka ibe lixesha ngaphezu amasuntswana malunga 0.5 ngaphezu kwisakhelo. Ukwenza izibalo ngqo ngakumbi kucetyiswa ukuba bahlole ngokweenkcukacha amaxwebhu zobuchwepheshe ezisetyenziswa yi uthotho lezibuko le esisebenza.
• Ukususela samaza, receiver, mhlawumbi, RS-485 converter oludityaniswe umgca enye, abakhe umamkeli ndiyabona njengoko transfer olwenziwe samaza yayo. Kudla ngokuthi kwiinkqubo ephawuleka yofikelelo oluzenzekelayo kumgca, lo msebenzi osemqoka lisetyenziswa kwinkqubo sokuhlola phakathi kwezigaba zidlulisele ezimbini. Kwiinkqubo eziqhelekileyo esebenza ngokungqinelana "inkosi-khoboka", kule nkqubo transfer Kucetyiswa ukuba ukuvala ngokupheleleyo angaluphazamisa ephuma kwisamkeli.

Oqwalaselo "ibhasi" ifomathi

Le ujongano inika ithuba yokudibanisa izixhobo kwi ubungakanani "ibhasi" xa zonke izixhobo kunye usebenzisa iperi enye macingo. Kulo mzekelo, umgca wonxibelelwano nto compulsorily kuvunyelwene resistors EOL kwiincam zombini.

Ukuqinisekisa ukuvumelana esekwe kulo mzekelo resistors luphawulwa ukuxhathisa 620 ohms. Bona basoloko efakwe kwisixhobo zokuqala nezokugqibela ezifakelwe emgceni. izixhobo Advantageously kakhulu mihla langoku ngaphakathi ukuxhathisa ofanayo, leyo ngokhetho kufakwa ngokubeka Jumpers kwibhodi isixhobo ekhethekileyo emgceni.

Ekubeni urhulumente wokuziswa kweencwadi Oxhumayo ekuqaleni efakwe, kuyimfuneko ekuqaleni ukususa kuzo zonke izixhobo, ngokulandelelana, ngaphandle kuqala nezokugqibela ezifakelwe emgceni. Umfuziselo zabaphindayo converters S2000-PI yemveliso efana ukuvimba ngamnye ivulwa yi uneswitshi, ngoxa izixhobo S2000-COP lubonakala C2000-K oluHlangeneyo asisule ukuvimba, apho ibhulorho, kuyimfuneko ukuba libe ayikho.

Ukuze kuqinisekiswe umgca elide zonxibelelwano, kucetyiswa ukuba usebenzise baphinda ezizodwa, transponder, afakelwe ulwalathiso ukutshintshwa oluzenzekelayo ngokupheleleyo.

Uqwalaselo wefomathi "inkwenkwezi"

Naliphi na isebe le migca RS-485 abantu akunqwenelekile, ngenxa yokuba kule meko kukho ubugqwetha womelele ngokwaneleyo umqondiso, kodwa ukusuka kwindawo ezenziwayo, banako ukuthintela kwimeko apho kukho ubude encinane amasebe. Kule meko ingakufuni ufakelo resistors kumasebe ahlukeneyo.

Le RS-485 isixokelelwano sabasasazi, nto leyo ilawulwa kwiqela lenjongo, kwaye ukuba icebo lokugqibela eqhagamshelwe kumgca efanayo, kodwa abondliwayo evela kwimithombo eyahlukeneyo, kuya kufuneka ukuba kudibanisa umxokelelwane 0 zonke izixhobo kunye kude ukuze kuqinisekiswe ulungelelwaniso nekhono zabo. Ukuba le mfuneko ayanelanga, ngoko ke ulawulo okude babe uxhulumaniso iyahlozinga kuzo izixhobo. Ukuba le ntambo ukuba ezakusetyenziswa eziliqela ngezibini ngocingo, ephothiweyo, kule meko ngenxa yesekethe ngokulinganisa enokwenzeka zingasetyenziswa isibini free ngokupheleleyo xa kuyimfuneko. Phakathi kwezinye izinto, kwakhona inika ithuba usebenzisa isikali wayivalela ephothiweyo kwimeko akukho moya emhlabeni.

Zintoni ekufuneka ndiziqondile?

Advantageously oluninzi lwangoku bekuza uhamba ngocingo equipotential, ukuba incinane ngokwaneleyo, kodwa kwimeko 0 V izixhobo okanye ngokwabo imithombo amandla uqhagamshele iibhasi zasekuhlaleni eziliqela oyicinezelayo umahluko enokubakho phakathi kwiziphaluka ezahlukeneyo 0V abe units eziliqela, kwaye kwezinye iimeko, nkqu amashumi volts, ngoxa ngoku ayahamba na wesekethe ukulinganiswa enokwenzeka kunokuba kakhulu ezibalulekileyo. Oku ngoyena nobangela oqhelekileyo yokuba kukho unxibelelwano ezingazinzanga phakathi kwe remote nengcinga, ukuze nokuba asilele.

Kungenxa yesi sizathu ukuba ufuna ukuvala amathuba yesekethe komhlaba 0 okanye, maxa amaninzi, ukuyincula lo mxokelelwane kwezinye kwindawo ethile. Kufuneka kwakhona ukuqwalasela amathuba unxulumano phakathi 0 kunye chain nomhlaba olukhuselayo ezikhoyo nezixhobo ezisetyenziswa kwinkqubo operatives.

Kwiziza, obubonakala ngokuba yincwadi evuliweyo bume kakhulu enzima umoya, inikeza ikhono qhagamshela intambo inethiwekhi ngokusebenzisa i "wasikhusela isibini ezijijekileyo". Kulo mzekelo, ukuze sibekho asezantsi umda lomqolo, ukususela capacitance ye intambo iphezulu.