Kev lag luam kev lag luam nthuav dav dav dav ntawm qhib- lub voj kab sib txuas tswj uas feem ntau yog raws li qhov sib txawv (on/off) signals; cov tshuab no ua haujlwm raws li cov kev xav tau tshwj xeeb thiab lub sijhawm ua ntu zus. Tsis tas li ntawd, muaj cov kev tswj hwm kev tswj hwm- ywj pheej ntawm kev txiav txim raws sij hawm lossis sij hawm- uas ua kev cuam tshuam kev nyab xeeb raws li kev sib raug zoo. Tsis tas li ntawd, muaj ntau cov ntaub ntawv tau txais thiab kev saib xyuas ntawm kev sib cais- xeev tsis sib xws- xws li hloov txoj haujlwm, mem tes signals, timers, counters, thiab analog teeb liab txwv lub tswb ceeb toom- uas yog lub hauv paus tseem ceeb rau kev saib xyuas. Tsav los ntawm cov kev tswj hwm thiab kev saib xyuas tshwj xeeb no, PLC tau hloov mus rau hauv cov khoom tsim los hloov ib txwm relay-raws li circuitry thiab ua kom yooj yim rau kev tswj hwm. PLC cov tuam txhab tau nce qib sib txuas ntau yam kev sib txuas lus hauv lawv cov CPU modules; Nyob rau tib lub sijhawm, kev nce qib ntawm kev sib tw ntawm fieldbus thiab Ethernet thev naus laus zis tau nthuav dav dav ntawm PLC daim ntawv thov. Kev ua lag luam muaj txiaj ntsig ntawm PLC yog qhov tseem ceeb los ntawm nws qhov txiaj ntsig zoo: kev ruaj ntseg, kev ntseeg siab, tus nqi-kev ua tau zoo, kev ua haujlwm zoo, kev siv tau yooj yim thiab yooj yim, thiab yooj yim ntawm kev khiav lag luam thiab kev saib xyuas.
Kho vajtse architecture ntawm PLC maub los nws tus kheej siv cov qauv, "tsev-block" qauv. Nws feem ntau muaj lub backplane (motherboard), digital I/O modules, analog I/O modules, thiab tshwj xeeb modules -xws li positioning modules thiab barcode recognition modules. Cov neeg siv tuaj yeem tau txais qhov xav tau ntawm I / O cov ntsiab lus los ntawm kev nthuav dav cov kab ke ncaj qha rau ntawm lub dav hlau rov qab lossis los ntawm kev siv cov tshuab tsheb npav los siv cov chaw nres tsheb I/O cov qhev nyob deb.
Thaum ua kom yooj yim rau kev tswj hwm qhov sib txawv ntawm I / O cov ntsiab lus, PLC kuj muaj lub peev xwm los tawm cov analog voltages thiab cov pulses digital. Qhov no ua rau nws tswj tau ntau yam khoom siv uas muaj peev xwm txais tau cov teeb liab zoo li no -xws li servo motors, stepper motors, thiab sib txawv - zaus tsav. Tsis tas li ntawd, nrog kev txhawb nqa ntawm kov-screen-raws li Tib neeg-Machine Interfaces (HMIs), PLC muaj peev xwm ua tau raws li cov neeg siv khoom xav tau ntawm txhua theem ntawm cov txheej txheem tswj.