Ukuvala uMsantsa: Ulwazi oluBalulekileyo loNxibelelwano lwe-PLC kwiiNgcali zoMbane
Ukuvala uMsantsa: Ulwazi oluBalulekileyo loNxibelelwano lwe-PLC kwiiNgcali zoMbane
Uthotho loNxibelelwano Basics
Unxibelelwano lothotho yiprotocol eqhelekileyo yesixhobo - ukuya kwisixhobo sokutshintshiselana ngedatha. Ngokungafaniyo ne-USB, uninzi lweekhompyuter zinee-RS232-ezisekwe kwi-serial port. Izibuko uthotho nazo ngokubanzi kusetyenziswa isixhobo kunye nedatha ekude - izixhobo zokufumana.
IiParameters eziphambili zoNxibelelwano lweSerial
Kunxibelelwano olusebenzayo lothotho, ezi parameters zilandelayo kufuneka zihambelane kumazibuko onke:
Inqanaba le-Baud: Imilinganiselo yedatha - isantya sothumelo kwiibits ngomzuzwana. Umzekelo, 300 baud ilingana 300 bits ngomzuzwana. Ireyithi ye-Baud ichaphazela ngokuthe ngqo ukuphindaphinda kwesampulu kumgca wedatha. Amazinga aphezulu e-baud, aququzelela umgama omfutshane - umgama omfutshane, unxibelelwano olukhawulezayo, alulungelelaniso lomgama wothumelo.
Amasuntswana eDatha:Bonisa eyona datha kuthumelo. Amaxabiso asemgangathweni yi-5, 7, okanye i-8 bits. Ngokomzekelo, i-ASCII eqhelekileyo isebenzisa iibhithi ezi-7, ngelixa i-ASCII eyandisiweyo isebenzisa 8. Ukhetho luxhomekeke kwidatha ethile - iimfuno zothumelo.
Misa amasuntswana:Phawula isiphelo sepakethe yedatha, ngokwesiqhelo ngexabiso lika-1, 1.5, okanye 2 bits. Banceda izixhobo zilungelelanise iiwotshi ngexesha lonxibelelwano. Iibhithi zokumisa ezongezelelekileyo zonyusa ukunyamezela iwotshi - iyantlukwano yexesha kodwa yehlisa idatha - izinga losulelo.
I-Parity Bit:Impazamo elula - ukujonga indlela. Iinketho ziquka ngokulinganayo, okungaqhelekanga, okuphezulu, okuphantsi, okanye akukho nanye. I-Even kunye ne-odd parity iseti i-parity bit ukuqinisekisa inani elilinganayo okanye elingaqhelekanga lamasuntswana aphezulu kwidatha egqithisiweyo. I-parity ephezulu kunye nesezantsi ngokulula ukuseta isuntswana kwingqiqo ephezulu okanye ephantsi, ivumela izixhobo ezifumanayo ukuba zibone uphazamiseko olunokubakho lonxibelelwano okanye ukungavumelani.
IiNdibaniselwano ze-PLC eziqhelekileyo
RS - 232:Umgangatho we-RS - 232 uqhelekile kwi-IBM - iPC kunye neenkqubo ezihambelanayo. Ixhasa usetyenziso olwahlukeneyo njengeempuku eziqhagamshelayo, abashicileli, iimodem, kunye nezixhobo zoshishino. Ngelixa RS - 232 yenza inqaku - ukuya - indawo yonxibelelwano phakathi kwezibuko ze-serial ze-PC kunye nezixhobo, umgama wayo ophezulu wokuhambisa unyawo lwe-50.
RS - 422:I-RS - 422, esetyenziswe kwiikhomputha ze-Apple Macintosh, isebenzisa ukubonakaliswa kweempawu. Ngokungafaniyo ne-RS - i-232 enye - iphelile umhlaba - umqondiso okhankanywe, i-RS - i-422 yokuhanjiswa kokwahlukana isebenzisa imigca emibini yokuthumela nokufumana iimpawu. Oku kwandisa ukhuseleko lwengxolo kwaye kwandise umgama wothumelo, kuyenze ilungele useto lwemizi-mveliso.
RS - 485:I-RS - 485 iphucula kwi-RS - 422 ngokuxhasa ukuya kwii-32 izixhobo kunye nokuchaza iimpawu zombane ubuninzi - isixhobo - ukubala iimeko zokuqinisekisa umbane wesignali owaneleyo. Ivumela ukudalwa kweenethiwekhi zesixhobo usebenzisa i-RS eyodwa - i-422 port. Ngengxolo eyomeleleyo - i-immunity kunye nenkxaso yezixhobo ezininzi, i-RS - 485 ilungele usetyenziso lwemizi-mveliso efana nesakhiwo sothungelwano lwesixhobo esisasazwayo esiqhagamshelwe kwiiPC, abalawuli bokuqokelela idatha, ii-HMI, kunye nezinye iinkqubo zokusebenza. I-RS - i-485 yi-superset ye-RS - 422, eyenza ukulawula zonke i-RS - izixhobo ze-422 ezinemigama yokudlulisa ngaphezu kweenyawo ze-4,000.