I-Modbus phezu kwe-RS485: Umhlahlandlela Wokuhlaziya Nokusebenzisa Okujulile

Umkhakha we-automation yezimboni ushintsha njalo, futhi enhliziyweni yokuxhumana okusebenzayo ngaphakathi kwezinhlelo ze-automation kukhona i-protocol enamandla ye-Modbus kune-RS485. Le protocol yokuxhumana ihlale isikhathi eside, ibaluleke kakhulu ekuxhumaneni okuhambisanayo okungenamthungo phakathi kwamadivayisi ahlukahlukene.

Ekuqaleni yasungulwa ngasekupheleni kwawo-1970 yiModicon (manje eyiSchneider Electric), iModbus yaklanywa ukuze ivumele ukuxhumana kwedatha okuqhubekayo ngaphakathi kwezinhlelo zokwenza izinto ngokuzenzakalela. Ukuyihlanganisa nezinga le-RS485 eliqinile kunikeze izimboni indlela ethembekile nephumelelayo yokuxhumana phakathi kwemishini.

Lo mhlahlandlela uhlose ukunikeza ochwepheshe emkhakheni wokulawula izimboni ukuqonda okuyinkimbinkimbi kweModbus nge-RS485. Sizohlola izingxenye zayo, izindlela zayo zokusebenza, kanye nezinhlelo zokusebenza ezingokoqobo, sigcizelela ukubaluleka kwayo okuhlala njalo esimweni sanamuhla esisebenzisa ngokuzenzakalelayo.

Ukhiye wokuthatha

1.  Qonda izisekelo ze-RS485 kanye ne-Modbus protocols.
2. Funda izinzuzo zokusebenzisa i-Modbus kune-RS485 ekusebenzeni ngokuzenzakalela kwezimboni.
3.  Thola ukuqonda kokunqoba izinselele ezivamile zokusebenzisa.
4. Qhathanisa i-Modbus ne-RS485 nezinye izinqubo zokuxhumana.
5. Hlola izinhlelo zokusebenza ezisebenzayo kanye namathuba esikhathi esizayo eModbus nge-RS485.
6. 
   

Kuyini i-RS485?

7. Izinga le-RS485 liyiphrothokholi ehlonishwayo yokuxhumana okulandelanayo, eyenzelwe ukudlulisa idatha emabangeni amade ngempumelelo. Izimiso eziyisisekelo ze-RS485 zisekelwe ekusayineni okuhlukile, indlela ethuthukisa kakhulu ukuzivikela komsindo. Ngokusebenzisa ama-differential pairs ukudlulisa izimpawu, i-RS485 inganciphisa ukuphazamiseka okuvame ukuhlangana nakho ezindaweni zezimboni.
   
   
8. Isici esisodwa esihlukile sendinganiso ye-RS485 uhlobo lwayo lwe-half-duplex. Kuhlelo lwe-half-duplex, ukudluliswa kwedatha kungenzeka kuzo zombili izinhlangothi, kodwa hhayi ngasikhathi sinye. Lokhu kuhlanganiswa kuqinisekisa ukucaca futhi kuvimbela ukungqubuzana kwedatha, ikakhulukazi okubaluleke kakhulu ekusethweni okuyinkimbinkimbi.
   
   
9. I-RS485 ifana nokuxhumana okude. Ingagcina ukudluliswa kwedatha okuthembekile ebangeni elingafika kumamitha angu-4000, okwenza kube usizo kakhulu ezinhlelweni ezinkulu lapho ezinye izindinganiso zokuxhumana zingaphumeleli khona.
   
   

Isici	Incazelo
Izinga le-RS485	Iphrothokholi yebanga elide elithembekile ukuxhumana okulandelanayo.
Ukubonisana Okuhlukile	Ukuthuthukisa ukungavikeleki komsindo, okubalulekile ezindaweni zezimboni.
I-Half-Duplex	Ivumela ukudluliswa kwedatha okuqondiswa kabili kodwa hhayi ngesikhathi esifanayo.
Ukungavikeleki Komsindo	Kunciphisa ukuphazamiseka, kuqinisekisa ubuqotho bedatha.
Ukuxhumana Kwamabanga Amade	Kuyasebenza ukudluliswa kwedatha amabanga amade.

10. Empeleni, indinganiso ye-RS485 iyindlela eqinile yezidingo zokuxhumana ezikude, iphumelela kakhulu ekuvikeleni umsindo futhi ihlinzeka ngesevisi ethembekile ezindaweni zezimboni ezidinga kakhulu.
    
    

Iyini i-Modbus Protocol?

11. Iphrothokholi ye-modbus iyiphrothokholi yokuxhumana esetshenziswa kabanzi eyenzelwe amadivayisi ezimboni. Yasungulwa yi-Modicon ngo-1979, le phrothokholi ivumela amadivayisi ahlukahlukene kagesi ukuthi axhumane kahle kunethiwekhi, kungakhathaliseki ukuthi abakhiqizi bahluke kanjani.
    
    
12. Isici esibalulekile sephrothokholi ye-modbus ukwakheka kwayo kwe-master-slave. Kulokhu kusethwa, idivayisi eyinhloko ilawula inethiwekhi, ithumela imiyalo futhi yamukele idatha kusuka kudivayisi eyodwa noma ngaphezulu ye-slave. Inceku ngayinye ingaphendula kuphela emiyalweni evela ku-master, iqinisekisa ukushintshaniswa kwedatha okuhlelekile kanye nokuxhumana okunembile.
    
    
13. Iphrothokholi ye-modbus isekela izinhlobo ezimbili eziyinhloko: i-modbus RTU kanye ne-modbus ASCII. I-Modbus RTU ifaka idatha ngendlela ye-binary, okuthuthukisa izinga lokudluliswa kwedatha futhi kunciphisa ukubambezeleka. Ngokuphambene nalokho, i-modbus ASCII isebenzisa umbhalo ocacile wokufaka ikhodi yedatha, okwenza kube lula ukufunda nokulungisa amaphutha kodwa ngokuvamile kuhamba kancane kune-modbus RTU.
    
    
14. Le protocol yokuxhumana eguquguqukayo yamukelwa kabanzi kuzo zonke izinhlelo zokulawula zezimboni ezahlukahlukene. Ukulula kwayo maqondana nokusetha nokulungisa, kanye nekhono lokuhlanganisa namadivayisi amaningi, kwenze kwaba yindlela ejwayelekile yokuxhumana ezimbonini ezisukela ekukhiqizeni kuya ekuphathweni kwamandla.

15. 
    

Iyini i-Modbus RS-485?

Ukuhlanganisa iphrothokholi yeModbus nesendlalelo esingokoqobo se-RS485 kudala ukwakheka kokuxhumana okusebenzayo okwaziwa ngokuthi i-Modbus RS-485. Lokhu kuhlanganiswa kusetshenziswa kabanzi ezinhlelweni zokulawula zezimboni, kusebenzisa amandla wobubili ubuchwepheshe ukuthuthukisa ukudluliswa kwedatha kanye nokuthembeka kohlelo.

Ubuhle be-RS485 busekujuleni kwenethiwekhi yayo enamaconsi amaningi, okuvumela amadivayisi amaningi ukuthi axhumeke ebhasini elifanayo. Lokhu kusethwa kulungele iphrothokholi ye-Modbus, okuvumela ukuxhumana okuqondile phakathi kwamadivayisi amaningi ngaphandle kobunzima bokucushwa kwe-master-slave. Ngokusekela ama-node afinyelela ku-32 engxenyeni eyodwa yenethiwekhi, i-Modbus RS-485 yenza ngcono ukusebenza kahle kanye nokukhula kwezinhlelo zokulawula zezimboni.

Esinye sezici ezivelele zeModbus kune-RS485 izindlela zayo eziqinile zokuthola amaphutha. Le phrothokholi iqinisekisa ubuqotho bedatha ngamasu ahlukahlukene njengokuhlolwa kokulingana kanye nokuhlolwa kokuphindaphinda kwe-cyclic redundancy (CRC). Lawa masu okuthola amaphutha abalulekile ekugcineni ukuxhumana okuthembekile ezindaweni ezivame ukuba nomsindo kagesi kanye nokunye ukuphazamiseka.

Esinye isici esibalulekile se-Modbus RS-485 ukuqedwa kwebhasi. Ukuqedwa okufanele kuqinisekisa ubuqotho besignali ngokuvimbela ukubonakaliswa kwesignali okungaphazamisa ukudluliswa kwedatha. Ngokuvamile, ama-resistor okuqeda abekwa emaphethelweni ebhasi le-RS485 ukuze afane nokuphazamiseka kwekhebula, ngaleyo ndlela kuthuthukiswe ukusebenza kwenethiwekhi ye-Modbus.

Ngamafuphi, i-Modbus RS-485 ihlanganisa iphrothokholi eqinile ye-Modbus nesendlalelo esingokoqobo se-RS485 esiguquguqukayo, isungula ikhambi lokuxhumana elithembekile nelisebenzayo lezinhlelo zokusebenza zokulawula zezimboni. Ukusekelwa kwayo kokucushwa kwama-multi-drop, izindlela eziphelele zokuthola amaphutha, kanye nokuqedwa kwebhasi okudingekayo kugcizelela ukubaluleka kwayo ekuthuthukiseni ukusebenza kohlelo kanye nobuqotho.

Ubuchwepheshe beModbus nge-RS485

Ukuxhumana phakathi kwamadivayisi e-modbus master kanye ne-modbus slave kunethiwekhi ye-RS485 kuhilela inqubo eningiliziwe ukuqinisekisa ukushintshaniswa kwedatha okuphumelelayo. Inhliziyo yalokhu kuxhumana ilele ohlakeni lwedatha, oluthwala idatha ehlelekile kusukela ku-master kuya ku-slave kanye nokuphikisana nalokho.

Uhlaka lwedatha olujwayelekile ku-Modbus luqukethe izingxenye eziningana ezibalulekile: ikheli ledivayisi, ikhodi yomsebenzi, idatha, kanye nokuhlolwa kwe-crc. Ikheli ledivayisi likhomba umamukeli ohlosiwe, kuyilapho ikhodi yomsebenzi ichaza isinyathelo okufanele sithathwe. Idatha ihlanganisa ulwazi oludingekayo lwaleso senzo, kanti i-CRC (Cyclic Redundancy Check) iqinisekisa ubuqotho bedatha ngokuthola amaphutha ngesikhathi sokudluliselwa.

Ukuhlolwa kwe-crc kubalulekile ekutholakaleni kwamaphutha. Leli nani lamabhayithi amabili elifakwe ekugcineni kohlaka lwedatha livumela amadivayisi ukuqinisekisa ukunemba kwedatha etholiwe, okuthuthukisa ukuthembeka kokuxhumana.

Izidingo zehadiwe zokusebenzisa i-Modbus RS485 zifaka i-port eqondile yedivayisi ngayinye kanye nezintambo ezifanele ukuxhuma inethiwekhi. I-protocol stack kumadivayisi amabili e-master kanye ne-slave ilawula lokhu kuxhumana, iqinisekisa ukuthi amafreyimu edatha akhiwe kahle, athunyelwe, futhi amukelwe.

Nasi incazelo eningiliziwe yesakhiwo sohlaka lwedatha lwe-Modbus RS485:

Ukusebenzisa i-Modbus nge-RS485 ngempumelelo kudinga ukuqonda okucacile kwalezi zingxenye kanye nezindima zazo ngaphakathi kwe-protocol stack. Ukuvumelanisa phakathi kwehadiwe nesofthiwe kuqinisekisa ukuxhumana okungenamthungo, okwenza i-Modbus nge-RS485 ibe yisisombululo esiqinile sezinhlelo zokusebenza zezimboni.

Kungani Ukhethe iModbus kune-RS485?

Izitayela Ezivelayo kanye Nombono Wesikhathi Esizayo