I. Kev Taw Qhia
Hauv kev lag luam automation, PLC (Programmable Logic Controller) thiab DDC (Direct Digital Control) yog ob qho kev tswj hwm feem ntau. Txhua tus muaj cov qauv kev ua haujlwm tshwj xeeb, cov yam ntxwv ua haujlwm, thiab cov xwm txheej siv tau, muab ntau txoj kev daws teeb meem rau kev lag luam automation. Daim ntawv no yuav muab cov ntsiab lus ntxaws ntxaws thiab kev txheeb xyuas cov yam ntxwv ntawm PLC thiab DDC, nrog rau kev tsom mus rau kev tshawb nrhiav lawv qhov sib txawv.
II. Kev txhais, yam ntxwv, thiab kev siv ntawm PLC
Txhais
PLC yog lub tshuab hluav taws xob digital tshwj xeeb tsim los rau kev lag luam. Nws siv programmable nco los khaws cov lus qhia rau kev ua haujlwm ntawm kev ua haujlwm, kev tswj xyuas raws sijhawm, sijhawm, suav, thiab suav lej. Los ntawm digital lossis analog inputs thiab outputs, nws tswj ntau hom tshuab lossis cov txheej txheem ntau lawm.
Yam ntxwv
(1) Zoo tiag tiag - Sijhawm Ua Haujlwm:PLCs muaj qhov muaj peev xwm ua tau zoo tiag tiag- lub sijhawm ua haujlwm, ua kom cov lus teb sai sai rau cov kev hloov pauv hauv thaj chaw ib puag ncig thiab kev siv cov tswv yim tswj hwm.
(2) Kev ruaj ntseg siab:PLCs ntiav cov qauv tsim qauv, muab kev ruaj ntseg thiab kev ntseeg siab rau kev ua haujlwm ruaj khov hauv kev lag luam hnyav.
(3) Flexibility:PLC tswj cov kev pab cuam tuaj yeem sau thiab hloov kho raws li qhov xav tau tiag tiag, ua raws li kev tswj hwm ntau yam xav tau.
(4) Yooj yim ntawm Programming:PLCs ntiav "natural language" programming oriented to control process, ua programming straightforward, yooj yim to taub, thiab yooj yim kawm thiab txawj.
(5) Scalable:Ob qho tib si kho vajtse thiab software Cheebtsam ntawm PLCs tuaj yeem nthuav dav kom haum rau kev lag luam automation systems ntawm ntau qhov sib txawv thiab qhov nyuaj.
Daim ntawv thov
PLCs tau siv dav dav thoob plaws ntau hom kev lag luam automation, suav nrog cov tshuab tsim khoom, kev ua tshuaj lom neeg, tsim hluav taws xob, thiab metallurgy. Lawv tswj kev ua haujlwm ntawm cov cuab yeej siv tshuab, saib xyuas cov haujlwm ua haujlwm, thiab kho cov chaw ua haujlwm kom txhim kho kev tsim khoom thiab txo cov nqi tsim khoom.
III. Kev txhais, yam ntxwv, thiab kev siv ntawm DDC
Txhais
DDC yog ib qho system uas siv cov khoos phis tawj kom ua tiav kev tswj hwm ntawm cov txheej txheem ntau lawm. Nws ntiav lub khoos phis tawj lossis tus maub los txhawm rau txheeb xyuas cov kev tswj tsis tau, ua cov lej raws li cov txheej txheem thiab tswj cov txheej txheem, thiab tom qab ntawd tso tawm cov txiaj ntsig rau cov actuators los tswj cov txheej txheem tsim khoom, tswj cov kev tswj tsis tau ntawm cov nqi teev tseg. DDC feem ntau yog siv rau kev saib xyuas thiab tswj cov tshuab hauv tsev, xws li kev tswj hwm hauv nruab nrab ntawm cov teeb pom kev zoo, cua txias, cua sov, thiab cov khoom siv cua.
Yam ntxwv
(1) Direct Control:DDC systems ncaj qha tswj cov cuab yeej siv hauv teb tsis muaj cov neeg nruab nrab ntxiv, txhim kho kev tswj lub teb thiab kev ua haujlwm zoo.
(2) Digital Control:Siv cov teeb liab digital thiab tshuab computer, DDC systems muab siab precision thiab kev ntseeg siab.
(3) Kev tswj xyuas:Kev saib xyuas tej thaj chaw deb thiab kev tswj hwm ntawm tes hauj lwm pab kom cov neeg siv saib xyuas qhov xwm txheej txhua lub sijhawm.
(4) High Flexibility:Kev tswj cov tswv yim tuaj yeem hloov kho dynamically kom tau raws li kev ua haujlwm ntau yam.
Daim ntawv thov
DDC cov tshuab feem ntau yog siv rau hauv kev saib xyuas thiab tswj cov ntawv thov, suav nrog cov tsev ntse, chaw ua haujlwm, thiab tsev kho mob. Lawv tswj cov teeb pom kev zoo, HVAC, thiab lub tshuab ua pa kom txhim kho cov neeg nyob hauv kev nplij siab thiab ua kom lub zog ua haujlwm zoo.
IV. Qhov sib txawv ntawm PLC thiab DDC
Keeb kwm thiab kev loj hlob
PLC yog thawj zaug tsim los hloov cov kev sib txuas sib txuas, thaum DDC hloov kho los ntawm PLC thev naus laus zis, tshwj xeeb tsim los ntawm cov tuam txhab tsim khoom lag luam rau lub tsev lag luam automation. DDC suav nrog ua ntej- cov haujlwm ua haujlwm sab hauv, nrog rau lwm yam kev ua haujlwm zoo ib yam li PLC.
Structure thiab Composition
PLCs ua haujlwm raws li cov tswj hwm, feem ntau ua haujlwm rau kev tswj hwm hauv nruab nrab ntawm cov ntsiab lus tshwj xeeb ntawm cov kab ntau lawm. Cov kab ke tsim los ntawm PLCs yog sib cuam tshuam los ntawm kev sib koom ua ke ntawm fieldbus. DDC, txawm li cas los xij, siv kev tswj hwm kev faib tawm los ntawm cov txheej txheem hierarchical architecture muaj peev xwm ntawm taw tes - mus rau - taw tes kev sib txuas lus.
Kev sib txuas lus raws tu qauv
PLCs txhawb nqa kev teeb tsa software tseem ceeb, uas muaj kev qhib siab thiab pab txhawb kev koom ua ke nrog cov khoom thib peb - tog. Lawv cov kev cai network feem ntau ua raws li cov qauv kev lag luam. Hloov pauv, DDC cov tuam txhab tsim kho software yog tus tswv, feem ntau sib koom ua ke tsuas yog siv cov khoom siv Lonworks thiab BACnet raws tu qauv. Cov txheej txheem no feem ntau haum rau cov cuab yeej tswj tsev, nrog rau kev tswj cov khoom siv feem ntau tsis muaj kev txhawb nqa rau lawv.
Daim ntawv thov Scenario
PLCs tau dav siv thoob plaws ntau hom kev lag luam automation, suav nrog kev tsim khoom, kev tsim tshuaj, kev tsim hluav taws xob, thiab metallurgy. DDC systems, qhov sib txawv, feem ntau yog siv rau hauv tsev saib xyuas thiab tswj cov chaw xws li cov tsev ntse, chaw ua haujlwm, thiab tsev kho mob.
V. Summary
Raws li ob lub ntsiab lus tswj hwm hauv kev lag luam automation, PLC thiab DDC txhua tus muaj cov yam ntxwv sib txawv thiab qhov zoo. PLC txhawb nqa nws qhov muaj zog tiag tiag - lub sijhawm ua haujlwm muaj peev xwm, ruaj khov, thiab hloov tau yooj yim rau kev siv dav hauv ntau hom kev lag luam automation. Hloov pauv, DDC ua tau zoo hauv kev saib xyuas lub tsev thiab kev tswj hwm los ntawm nws txoj kev tswj hwm ncaj qha, kev tswj hwm digital, thiab kev tswj hwm cov yam ntxwv. Kev nkag siab txog cov kev sib txawv no ua rau muaj kev paub ntau ntxiv txog kev xaiv thiab siv cov kev tswj hwm no kom tau raws li cov kev xav tau ntawm kev lag luam automation.