RS485 gas detectors siv 4-core shielded wires, 2 fais fab kab, thiab 2 teeb liab kab. Qhov kis tau tus mob nyob deb kuj ntev, txog 1-2Km; 4-20mA gas detectors siv peb-core xov hlau, ib lub hwj chim qaum thiab ib lub teeb liab kab. Qhov kev ncua deb yog luv luv, nyob rau hauv 1 km.
Qhov zoo ntawm RS485 cov teeb liab:
Lub teeb liab sib koom ua ke thiab qhov tshwm sim ntawm kev ua tsis tiav yog tsawg. Lub RS485 cov teeb liab digital tsis muaj qhov tsis yooj yim li ntawd. Cov ntaub ntawv raug xa mus rau tib daim ntawv ntawm cov ntaub ntawv kab, uas txhim kho kev ntseeg siab ntawm cov ntaub ntawv. Kev xaim yog qhov yooj yim thiab kev ua haujlwm me me. Qhov pom tseeb zoo ntawm lub tsheb npav yog cov xaim tsawg dua, kev xaim yooj yim, thiab tus nqi qis. Rau RS485 cov teeb liab teeb liab, ob lub teeb liab kab thiab ob kab hluav taws xob, cov xov hluav taws xob yog qhov yooj yim thiab yooj yim.
Disadvantages ntawm RS485 system:
Teeb liab ncua sij hawm: Cov ntaub ntawv yog txhuam tawm ib qho los ntawm ib qho, uas yog tshwj xeeb tshaj yog pom tseeb thaum muaj ntau qhov kev sojntsuam. Fais fab mov teeb meem. Tag nrho cov probes yog powered centrally los ntawm tus tswv tsev. Thaum muaj ntau qhov kev sojntsuam thiab lub peev xwm ntawm lub zog ntawm tus tswv tsev tsis txaus, cov khoom siv hluav taws xob hauv zos yuav tsum muaj.
Qhov zoo ntawm 4-20mA analog teeb liab system:
Cov ntaub ntawv synchronization yog qhov zoo thiab cov khoom siv hluav taws xob tsis txwv. Piv nrog rau lub tsheb npav, txhua lub tshuab hluav taws xob hauv cov kab hluav taws xob sib txuas lus nrog tus tswj nws tus kheej, uas tuaj yeem xa cov xwm txheej ntawm qhov chaw mus rau qhov chaw tswj kom raws sijhawm, kom cov neeg saib xyuas tuaj yeem txiav txim tau raws sijhawm thiab zoo, thiab cov cuab yeej tswj xyuas cov khoom siv peripheral tuaj yeem ua tau raws sijhawm Ua kom muaj kev tswj xyuas kom tsis txhob muaj xwm txheej txaus ntshai.
Qhov tsis zoo ntawm 4-20mA analog teeb liab system:
Cov kab hluav taws xob yog qhov nyuaj. Teeb liab cuam tshuam loj. Tus nqi ntawm cov xaim yog qhov loj, kev ua haujlwm loj, kev xaim yog qhov nyuaj, kev teeb tsa thiab kev tsim kho yog qhov nyuaj, thiab kev teeb tsa thiab cov khoom siv raug nqi siab.
Cov teeb liab tso tawm ntawm cov khoom siv roj ruaj ruaj muaj xws li hauv qab no:
1. 4-20mA analog teeb liab tso zis
Lub 4-20mA analog teeb liab tso zis hluav taws xob ntes yog ib qho cuab yeej tsim los ntawm peb lub tuam txhab uas tuaj yeem tshawb xyuas tsis tu ncua ntawm cov tshuaj lom neeg, tsim kev puas tsuaj, hluav taws kub thiab tawg hauv qhov chaw ua haujlwm. Lub detector ntes roj concentration los ntawm ntuj diffusion thiab siv imported sensors nrog zoo rhiab heev thiab zoo heev repeatability. Siv ua ke nrog cov roj ceg kab tswj txee tsim los ntawm peb lub tuam txhab, ib lub txee tswj tau tuaj yeem txuas nrog ntau ceg kab kev sojntsuam. Cov zis hom yog ob-hlau lossis peb-xaim. Peb-xaim roj xa hluav taws xob tuaj yeem tso tawm ib txheej ntawm relay switching signals. Qhov kev ncua deb ntawm kis yog 1000 meters. Ob-xaim roj xa hluav taws xob siv ob-core shielded cable nrog hla ntu ntawm 2 × 1.5mm2. Peb-xaim roj xa hluav taws xob siv peb-core shielded cable ntawm 3 × 1.5mm2 (cov ntaub thaiv npog tuaj yeem tiv thaiv qhov chaw qhuav ntawm lwm cov teeb liab), lub zog hluav taws xob ntawm kev sojntsuam roj hauv txoj kev txuas no yog muab los ntawm Gas tswj txee (24V DC)