Kwicandelo le-automation yemizi-mveliso kunye nolawulo lwenkqubo, imveliso ye-4 - 20mA ngumgangatho oqhelekileyo nobalulekileyo wokudluliselwa kwesignali ye-analog. Ukuqonda imigaqo yayo, iimpawu kunye nokusetyenziswa kwayo kubalulekile kwiingcali kwezi nkalo, kunye nakubani na onomdla ekusebenzeni okuntsonkothileyo kweenkqubo zanamhlanje zoshishino.
Isiphumo se-4 - 20mA sibhekisa kwinkqubo ye-electric current loop apho isignali imelwe yi-direct - current (DC) electrical current eyahluka phakathi kwe-4 milliamperes (mA) ukuya kwi-20mA. Apha, "mA" imele i-milliamperes, iyunithi ye-electrical current. Kule nkqubo, i-4mA idla ngokumela ixabiso elingu-zero okanye elincinci le-variable elinganisiweyo, ngelixa i-20mA ihambelana nexabiso eliphezulu. Umzekelo, kwisicelo sokuvavanya ubushushu, i-4mA ingabonisa ubushushu obuyi-0 degrees Celsius, kwaye i-20mA ingabonisa ubushushu obuyi-100 degrees Celsius, kuxhomekeke ekulinganisweni kwe-sensor kunye nenkqubo.
Umgaqo osemva kokuphuma kwe-4 - 20mA ukwikhono layo lokudlulisa ulwazi kumgama omde olunobuthathaka obuphantsi kwingxolo yombane kunye nokuphazamiseka. Ngokungafaniyo nemiqondiso ye-analog esekelwe kumbane, enokuchaphazela ngokulula ukumelana kwiintambo zothumelo kunye neendawo zangaphandle ze-electromagnetic, imiqondiso ye-current-loop igcina ukuthembeka kwayo ngcono. Oku kungenxa yokuba umbane ohamba kwi-loop uhlala ungaguquki nokuba uxhathiso lwentambo lunjani, logama nje umbane unokubonelela nge-voltage eyaneleyo yokunqoba ukumelana kwi-loop. I-sensor ekupheleni komthombo we-loop, njenge-sensor yoxinzelelo okanye i-flow meter, iguqula ubungakanani obubonakalayo obuyilinganisayo (uxinzelelo, ukuhamba, njl.njl.) ibe ngumbane wombane ngaphakathi koluhlu lwe-4 - 20mA. Lo mbane emva koko uhamba ngesekethe ye-wire-two okanye ye-four-wire ukuya kwisiphelo sokwamkela, apho uguqulwa ubuye ube yisignali esebenzisekayo, njengokufunda kwisibonisi okanye igalelo lenkqubo yolawulo.
Enye yeenzuzo ezibalulekileyo zomphumo we-4 - 20mA kukuba ikwazi ukuxhasa izixhobo "ezisebenza nge-loop". Kwisetingi eqhutywa nge-loop, iingcingo ezimbini ezifanayo ezithwala isignali yangoku nazo zibonelela ngombane kwi-sensor okanye kwi-transmitter. Oku kwenza lula ukufakelwa kwentambo kwaye kunciphisa iindleko zokufakela, ingakumbi kwizityalo ezinkulu zoshishino ezinee-sensor ezininzi kunye nezixhobo. Ukongeza, umgangatho we-4 - 20mA uvumela ukuba kube lula ukubona iimpazamo kwinkqubo. Ekubeni i-0mA ingeyona inxalenye yoluhlu oluqhelekileyo lokusebenza (ubuncinci yi-4mA), ukufundwa kwe-0mA okanye umbane ngaphandle koluhlu lwe-4 - 20mA kudla ngokubonisa ingxaki, njengocingo oluphukileyo, i-sensor engasebenzi kakuhle, okanye ingxaki ngombane.
Imveliso ye-4 - 20mA isetyenziswa kakhulu kumashishini ahlukeneyo. Kwishishini leoyile negesi, isetyenziselwa ukudlulisa idatha ukusuka kwiiparameter zokujonga iisensa ezifana noxinzelelo lwemibhobho, amazinga okuhamba kolwelo, kunye namanqanaba eetanki ukuya kumagumbi olawulo oluphakathi. Kwizityalo zokuvelisa, inceda ekulawuleni nasekujongeni iinkqubo ezifana nobushushu, umswakama, kunye noxinzelelo lweekhemikhali kwiireactors. Kwicandelo le-automation yesakhiwo, imiqondiso ye-4 - 20mA isetyenziselwa ukulawula iinkqubo zokufudumeza, zokungenisa umoya, kunye ne-air-conditioning (HVAC), ukulungisa iiparameter ngokusekelwe kufundo lweesensa zokusingqongileyo.
Ukuqukumbela, imveliso ye-4 - 20mA yindlela esisiseko nethembekileyo yokudlulisa isignali ye-analog kwiindawo zoshishino kunye nolawulo lwenkqubo. Ukuqina kwayo ngokuchasene nengxolo, inkxaso yezixhobo ezisebenza nge-loop, kunye nokulula kokufumanisa iimpazamo kuye kwenza ukuba ibe lukhetho olukhethwayo kwizicelo ezininzi, okuqinisekisa ukusebenza kakuhle kunye nolawulo olufanelekileyo lweenkqubo zoshishino kwihlabathi liphela. Njengoko itekhnoloji iqhubeka nokukhula, umgangatho we-4 - 20mA unokudibana neenkqubo ezintsha zonxibelelwano lwedijithali, kodwa ukubaluleka kwayo kwicandelo le-analog-based industrial automation kusazinzile.
Ixesha leposi: Epreli-30-2025