Ndeipi pfungwa yeRS485 interface kutanga?
Muchidimbu, chiyero chemaitiro emagetsi, ayo anotsanangurwa neTelecommunications Industry Association uye Electronic Industries Alliance. Iyo dhijitari yekutaurirana network ichishandisa chiyero ichi inogona kunyatso kufambisa masaini pamusoro pemadaro marefu uye munzvimbo dzine ruzha rwemagetsi. RS-485 inoita kuti zvikwanisike kugadzirisa zvinodhura zvemunharaunda network uye akawanda mapazi ekutaurirana zvinongedzo.
RS485 ine marudzi maviri ewaya: maviri waya system uye mana waya system. Iwo mana waya sisitimu anogona chete kuwana point-to-point kutaurirana uye haiwanzo kushandiswa ikozvino. Parizvino, iwo maviri waya system wiring nzira inonyanya kushandiswa.
Muuinjiniya husina kusimba hwazvino, kutaurirana kweRS485 kunowanzo tora nzira yekukurukurirana yetenzi-muranda, kureva, muenzi mumwe ane nhapwa dzakawanda.
Kana iwe uine nzwisiso yakadzama yeRS485, iwe uchaona kuti zvechokwadi mune yakawanda ruzivo mukati. Nokudaro, tichasarudza dzimwe nyaya dzatinowanzo funga mumagetsi asina simba kuti munhu wose adzidze uye anzwisise.
RS-485 Electrical Regulations
Nekuda kwekuvandudzwa kweRS-485 kubva kuRS-422, mitemo yakawanda yemagetsi yeRS-485 yakafanana neRS-422. Kana kutapurirana kwakaringana kwakagamuchirwa, zvinodzivirira zvekumisa zvinoda kubatanidzwa kune tambo yekutapurirana. RS-485 inogona kutora waya mbiri uye nzira ina dzewaya, uye iwo maviri waya sisitimu inokwanisa kuwana yechokwadi yakawanda-point bidirectional kutaurirana, sezvakaratidzwa mumufananidzo 6.
Paunenge uchishandisa ina waya yekubatanidza, seRS-422, inogona chete kuzadzisa-point-to-point kutaurirana, ndiko kuti, panogona kuve nechinhu chimwe chete chehunyanzvi uye zvimwe zvese zvishandiso zvevaranda. Zvisinei, ine kuvandudzwa kana ichienzaniswa neRS-422, uye inogona kubatanidza 32 mamwe madivayiri mubhazi zvisinei newaya ina kana maviri nzira yekubatanidza waya.
Iyo RS-485 yakajairika mode voltage kubuda iri pakati -7V uye + 12V, uye iyo shoma yekupinza impedance yeRS-485 inogamuchira i12k;, Mutyairi weRS-485 anogona kuiswa muRS-422 network. RS-485, senge RS-422, ine kureba kwekutapurirana kure kunosvika 1219 metres uye yakanyanya kutapurirana mwero we10Mb/s. Kureba kweiyo yakaenzana yakamonyoroka peya inopesana nechiyero chekutapurirana, uye iyo yakatsanangurwa yakanyanya kureba yetambo inogona kushandiswa chete kana kumhanya kuri pasi pe100kb/s. Mwero wepamusoro wekutapurirana unogona kuwanikwa chete pachinhambwe chipfupi. Kazhinji, huwandu hwekutakura hwemamita 100 kureba kwakamonyoroka peya ingori 1Mb/s. RS-485 inoda maviri ekumisa maresitorendi ane kukosha kwekupokana kwakaenzana neiyo hunhu impedance yetambo yekutumira. Kana uchitumira pachinhambwe chine rectangular, hapana chikonzero chekumisa resistor, icho chisingawanzo kudiwa pazasi 300 metres. Iyo yekumisa resistor yakabatana kumativi ese maviri ekufambisa bhazi.
Mapoinzi akakosha ekuisa network yeRS-422 uye RS-485
RS-422 inogona kutsigira 10 node, nepo RS-485 inotsigira 32 node, saka akawanda nodes anoumba network. Iyo network topology inowanzo tora terminal inofananidzwa bhazi chimiro uye haitsigire mhete kana nyeredzi network. Paunenge uchigadzira network, zvinotevera zvinofanirwa kucherechedzwa:
1. Shandisa tambo yakamonyoroka sebhazi uye batanidza node imwe neimwe munhevedzano. Hurefu hwemutsara unobuda kubva kubhazi kuenda kune imwe neimwe node hunofanirwa kuve hupfupi sezvinobvira kuderedza kukanganiswa kwechiratidzo chinoratidzwa mumutsara unobuda pachiratidzo chebhazi.
2. Kuchenjerera kuchabhadharwa kune kuenderera kwebhazi maitiro impedance, uye chiratidzo chechiratidzo chichaitika paKurongwa kwe discontinuities ye impedance. Mamiriro ezvinhu anotevera anogona kutungamirira nyore kune iyi discontinuity: zvikamu zvakasiyana-siyana zvebhazi zvinoshandisa tambo dzakasiyana, kana kune akawanda matransceivers akaiswa pedyo pamwe chete pane chimwe chikamu chebhazi, kana kuti mitsara yakareba yebazi inotungamirirwa kunze kwebhazi.
Muchidimbu, imwe, inoenderera chiratidzo chiteshi inofanira kupihwa sebhazi.
Maitiro ekutarisa kureba kwetambo yekutumira kana uchishandisa iyo RS485 interface?
Mhinduro: Paunenge uchishandisa iyo RS485 interface, iyo yakareba tambo yakareba inobvumirwa kutumira chiratidzo che data kubva kune jenareta kusvika kumutoro pane imwe nzira yekufambisa mutsara ibasa rezinga rechiratidzo che data, iro rinonyanya kuderedzwa nekukanganiswa kwechiratidzo uye ruzha. Hukama hwehukama pakati pehupamhi hwetambo kureba uye chiyero chechiratidzo chinoratidzwa mumufananidzo unotevera unowanikwa uchishandisa 24AWG copper core twisted pair tambo yerunhare (ine dhayamita yewaya ye0.51mm), ine mutsara wekupinda mutsetse wekupfuura capacitance ye52.5PF/M, uye kuguma kwekutakura mutoro we 100 ohms.
Kana chiyero chechiratidzo chedhata chadzikira kusvika pazasi 90Kbit/S, uchifungidzira kurasikirwa kwechiratidzo chinotenderwa kwe6dBV, kureba kwetambo kunogumira ku1200M. Muchokwadi, iyo curve mumufananidzo inochengetedza zvakanyanya, uye mukushandisa zvinoshanda, zvinokwanisika kuwana tambo yakareba kupfuura iyo.
Paunenge uchishandisa tambo dzine dhayamita dzakasiyana dzewaya. Iyo yakareba cable urefu yakawanikwa yakasiyana. Semuenzaniso, kana chiyero chechiratidzo che data chiri 600Kbit/S uye tambo ye 24AWG ikashandiswa, inogona kuonekwa kubva pamufananidzo kuti kureba kwetambo ndeye 200m. Kana tambo ye19AWG (ine dhayamita yewaya ye0.91mm) yakashandiswa, kureba kwetambo kunogona kuva kukuru kudarika 200m; Kana tambo ye28AWG (ine dhayamita yewaya ye0.32mm) ikashandiswa, kureba kwetambo kunogona kungove kushoma 200m.
Nzira yekuwana sei multi-point kutaurirana kweRS-485?
Mhinduro: Mutakuri mumwe chete anogona kutumira paRS-485 bhazi chero nguva. Hafu duplex modhi, ine chete tenzi muranda. Yakazara duplex modhi, iyo tenzi chiteshi inogona kugara ichitumira, uye chiteshi chevaranda chinogona chete kutumira kamwe chete. (Inodzorwa na uye DE)
Mumamiriro ezvinhu api panoda kushandiswa kweiyo RS-485 interface? Nzira yekuziva sei kukosha kwekupikisa? Maitiro ekugadzirisa terminal inoenderana resistors?
Mhinduro: Mukufambisa kwemasaini kureba, zvinowanzodikanwa kuti ubatanidze chigadziro chinofananidzira chinopikisa pamagumo ekugamuchira kudzivirira chiratidzo chekuratidzira uye echo. Iyo terminal inoenderana nekushomeka kukosha kunoenderana neiyo impedance maitiro etambo uye yakazvimirira pakureba kwetambo.
RS-485 inowanzo shandisa mapeji akamonyoroka (akadzivirirwa kana asina kuvharika) akabatana, ane magumo ekuramba kazhinji ari pakati pe100 ne140 Ω, ine kukosha kwakajairika kwe120 Ω. Mukugadzirisa chaiko, imwe terminal resistor yakabatana kune imwe neimwe yeaviri terminal node yetambo, iri padyo uye iri kure kure, nepo node iri pakati haigone kubatana kune terminal resistor, zvikasadaro zvikanganiso zvekutaurirana zvichaitika.
Sei iyo RS-485 interface ichine data yakabuda kubva kune inogamuchira kana kutaurirana kwamiswa?
Mhinduro: Sezvo RS-485 inoda kuti kutumirwa kwese kugonesa masaini ekudzora kuvharwa uye kugamuchira kunogonesa kuve kwakakodzera mushure mekutumira data, mutyairi webhazi anopinda munzvimbo yakakwira yekupikisa uye mugamuchiri anogona kutarisa kana paine data nyowani yekutaurirana mubhazi.
Panguva ino, bhazi riri mupassive drive state (kana bhazi riine chinomira chinoenderana nekupikisa, iyo yekusiyanisa nhanho yemitsara A uye B ndeye 0, iyo inogamuchira inobuda haina chokwadi, uye ine hanya nekushandurwa kwechiratidzo chekusiyanisa pa. mutsara AB; kana pasina chigadziriso chinofananidzwa, bhazi riri muHigh impedance state, uye kuburitsa kweanogamuchira hakuna chokwadi), saka iri panjodzi yekukanganiswa kweruzha rwekunze. Kana ruzha rweruzha ruchipfuura chikumbaridzo chechiratidzo chekupinza (yakajairika kukosha ± 200mV), mugamuchiri anoburitsa data, zvichiita kuti UART ienderane igamuchire data risingaite, zvichikonzera zvikanganiso zvekutaurirana zvinozotevera; Imwe mamiriro ezvinhu anogona kuitika panguva iyo kufambisa kunogonesa kutonga kunovhurwa / kuvharwa, zvichiita kuti mugamuchiri abudise chiratidzo, izvo zvinogona zvakare kukonzera UART kugamuchira zvisirizvo. Solution:
1) Mubhazi rekutaurirana, nzira yekukwevera kumusoro (A mutsara) pachikamu chimwe chete chekuisa uye kudhonzera pasi (B mutsara) kune yakatarisana chikamu chekuisa magumo inoshandiswa kusungirira bhazi, kuve nechokwadi chekuti mugamuchiri ari pa yakatarwa "1" level; 2) Tsiva iyo interface yedunhu neMAX308x akateedzana interface zvigadzirwa zvine yakavakirwa-mukati yekudzivirira nzira yekudzivirira; 3) Kubvisa kuburikidza nesoftware zvinoreva, ndiko kuti, kuwedzera 2-5 yekutanga kuwiriranisa mabheti mukati meiyo yekutaurirana data packet, chete mushure mekunge musoro wekuwiriranisa wasangana unogona kutaurirana chaiko data kutanga.
Signal attenuation yeRS-485 mumatambo ekutaurirana
Chinhu chechipiri chinokanganisa kutapurirana kwechiratidzo ndiko kudzikisira kwechiratidzo panguva yekufambiswa kwetambo. Tambo yekutumira inogona kuoneka sedunhu rakaenzana rinoumbwa nemubatanidzwa wekugovera capacitance, kugoverwa inductance, uye kuramba.
Iyo yakagoverwa capacitance C yetambo inogadzirwa zvakanyanya newaya mbiri dzakafanana dzepeya yakamonyoroka. Kupokana kwewaya kune zvishoma pachiratidzo pano uye kunogona kuregererwa.
Kupesvedzera Kwekugoverwa Kwesimba paKufambiswa Kwekuita kweRS-485 Bhazi.
Iyo capacitance yakagoverwa yetambo inonyanya kugadzirwa newaya mbiri dzakafanana dzepeya yakamonyoroka. Mukuwedzera, kunewo capacitance yakagoverwa pakati petambo uye pasi, iyo, kunyange zvazvo iri duku, haigoni kuregererwa pakuongorora. Iko kukanganiswa kwekugovera capacitance pakufambisa kwebhazi kunonyanya kukonzerwa nekufambiswa kwezviratidzo zvakakosha mubhazi, izvo zvinogona kuratidzwa chete mu "1" uye "0" nzira. Mune yakakosha byte, senge 0x01, iyo chiratidzo "0" inobvumira yakakwana yekuchaja nguva yeiyo yakagoverwa capacitor. Zvisinei, kana chiratidzo che "1" chasvika, nekuda kwekubhadhara mu capacitor yakagoverwa, hapana nguva yekubuda, uye (Vin +) - (Vin -) - ichiri yakakura kudarika 200mV. Izvi zvinoita kuti anogashira atende zvisirizvo kuti "0", zvinozotungamira kune CRC verification zvikanganiso uye iyo yese data furemu yekutapurirana kukanganisa.
Nekuda kwesimba rekugovera mubhazi, kukanganisa kwekufambisa data kunoitika, zvichikonzera kuderera kwekuita kwese network. Pane nzira mbiri dzekugadzirisa dambudziko iri:
(1) Deredza Baud yekufambisa data;
(2) Shandisa tambo dzine madiki akagoverwa capacitors kuti uvandudze kunaka kwemitsara yekutumira.
Tevera CF FIBERLINK kuti udzidze zvakawanda nezve hunyanzvi hwekuchengetedza !!!
Chirevo: Kugovana zvemhando yepamusoro nemunhu wese kwakakosha. Zvimwe zvinyorwa zvakatorwa kubva painternet. Kana pane kukanganisa, tapota tizivisei uye tichazvigadzirisa nekukurumidza sezvinobvira.
Nguva yekutumira: Jul-06-2023