Nkhani - Kulumikizana kwa RS485

Ndiukadaulo wokhwima komanso wotukuka wa SCM koyambirira kwazaka za 80, msika wa zida zapadziko lonse lapansi umayendetsedwa ndi ma metres anzeru, zomwe zimatengera zofuna zamabizinesi.Chimodzi mwazinthu zofunika kuti mabizinesi asankhe mita ndikukhala ndi mawonekedwe olumikizirana pa intaneti.Dongosolo loyamba la chizindikiro cha analogi ndi njira yosavuta, ndiye mawonekedwe a chida ndi mawonekedwe a RS232, omwe angathe kukwaniritsa kulankhulana molunjika, koma njira iyi siingathe kukwaniritsa ntchito yochezera, ndiye kutuluka kwa RS485 kumathetsa vutoli.

RS485 ndi muyezo womwe umatanthawuza mawonekedwe amagetsi a madalaivala ndi olandila pamakina ofananirako a digito.Muyezowu umatanthauzidwa ndi Telecommunications Industry Association ndi Electronics Industry Union.Maukonde olumikizirana pakompyuta omwe amagwiritsa ntchito mulingo uwu amatha kufalitsa ma siginecha bwino pamtunda wautali komanso m'malo aphokoso lamphamvu lamagetsi.RS-485 imapangitsa kusinthika kolumikiza maukonde akomweko komanso maulalo angapo olumikizirana anthambi.

Mtengo wa RS485ali ndi mitundu iwiri ya mawaya a mawaya awiri ndi mawaya anayi.Mawaya anayi amatha kukwaniritsa njira yolankhulirana yolunjika, yosagwiritsidwa ntchito kawirikawiri.Mawaya awiri opangira ma waya amagwiritsidwa ntchito kwambiri ndi mawonekedwe a mabasi ndipo amatha kulumikizidwa ndi ma node 32 nthawi zambiri mu basi yomweyo.

Mu netiweki yolumikizirana ya RS485, kulumikizana kwakukulu kumagwiritsidwa ntchito, ndiko kuti, mita yayikulu imalumikizidwa ndi mamita angapo.Nthawi zambiri, kulumikizana kwa ulalo wa RS-485 kumangolumikizidwa ndi mapeyala opotoka a "A" ndi "B" kumapeto kwa mawonekedwe aliwonse, ndikunyalanyaza kulumikizana kwapansi pazizindikiro.Njira yolumikizira iyi nthawi zambiri imatha kugwira ntchito bwino, koma yakwirira ngozi yobisika.Chimodzi mwa zifukwa ndi kusokoneza wamba mode: RS - 485 mawonekedwe utenga osiyana mode kufala njira ndipo safuna kudziwa chizindikiro ndi mawu aliwonse, koma zindikirani kusiyana voteji pakati pa mawaya awiri, zomwe zingachititse kusadziwa wamba mode voteji. osiyanasiyana.The RS485 transceiver common-mode voltage ranges pakati pa - 7V ndi + 12V ndi netiweki yonse imatha kugwira ntchito moyenera, pokhapokha ikakumana ndi zomwe zili pamwambapa,;Pamene wamba mode voteji ya mzere maukonde kuposa osiyanasiyana, kukhazikika ndi kudalirika kwa kulankhulana adzakhudzidwa, ndipo ngakhale mawonekedwe adzawonongeka.Chifukwa chachiwiri ndi vuto la EMI: gawo lodziwika bwino lachidziwitso cha dalaivala wotumiza likufunika njira yobwerera.Ngati palibe njira yochepetsera yobwerera (malo owonetsera), imabwerera kugwero ngati mawonekedwe a radiation, ndipo basi yonse idzatulutsa mafunde amagetsi kunja ngati mlongoti waukulu.

Miyezo yodziwika bwino yolumikizirana ndi RS232 ndi RS485, yomwe imatanthawuza ma voltage, impedance, ndi zina zambiri, koma osatanthauzira pulogalamu ya pulogalamuyo.Zosiyana ndi RS232, mawonekedwe a RS485 akuphatikizapo:

1. Makhalidwe amagetsi a RS-485: logic "1" imayimiridwa ndi kusiyana kwa magetsi pakati pa mizere iwiri monga + (2 — 6) V;Zomveka "0" imayimiridwa ndi kusiyana kwa magetsi pakati pa mizere iwiriyi monga - (2 - 6) V. Pamene mawonekedwe a chizindikiro cha mawonekedwe ndi otsika kuposa RS-232-C, sikophweka kuwononga chip cha dera la mawonekedwe, ndipo mulingowo umagwirizana ndi mulingo wa TTL, kotero ndikosavuta kulumikizana ndi dera la TTL.

2. Kuchuluka kwa data kufalikira kwa RS-485 ndi 10Mbps.

3. Mawonekedwe a RS-485 ndi amphamvu, ndiko kuti, kusokoneza kwabwino kwa phokoso.

4. The pazipita kufala mtunda wa RS-485 mawonekedwe ndi 4000 mapazi muyezo mtengo, Ndipotu akhoza kufika mamita 3000 (deta zongopeka, mu ntchito zothandiza, malire mtunda ndi pafupifupi 1200 mamita), kuwonjezera, RS-232 -C mawonekedwe amangolola kulumikiza 1 transceiver pa basi, ndiko kuti, mphamvu ya station imodzi.Mawonekedwe a RS-485 pabasi amaloledwa kulumikiza mpaka ma transceivers 128.Ndiko kuti, pokhala ndi masiteshoni ambiri, ogwiritsa ntchito amatha kugwiritsa ntchito mawonekedwe amodzi a RS-485 kuti akhazikitse makina ochezera mosavuta.

Chifukwa mawonekedwe a RS-485 ali ndi kusokoneza kwabwino kwa phokoso, zabwino zomwe zili pamwambapa za mtunda wautali wotumizira komanso kuthekera kokhala ndi masiteshoni ambiri kumapangitsa kuti ikhale mawonekedwe omwe amakonda.Chifukwa netiweki ya theka-duplex yopangidwa ndi mawonekedwe a RS485 nthawi zambiri imangofunika mawaya awiri, mawonekedwe a RS485 amatengera kufalikira kwa awiri opotoka.Cholumikizira cholumikizira cha RS485 chimagwiritsa ntchito chipika cha 9-core plug ya DB-9, ndipo mawonekedwe anzeru a terminal RS485 amagwiritsa ntchito DB-9 (bowo), ndipo mawonekedwe a kiyibodi RS485 olumikizidwa ndi kiyibodi amagwiritsa ntchito DB-9 (singano).