PLC muaj cov yam ntxwv ntawm ntau yam muaj zog, siv tau yooj yim, dav yoog raws, kev ntseeg siab, muaj peev xwm tiv thaiv kev cuam tshuam, thiab kev ua haujlwm yooj yim.
Lub International Electrotechnical Commission (IEC) txhais PLC nyob rau hauv nws cov qauv raws li: "Programmable logic controller yog ib qho hluav taws xob system rau cov lag luam digital, tshwj xeeb tshaj yog tsim rau daim ntawv thov nyob rau hauv ib puag ncig muaj. ua raws li cov neeg siv cov lus qhia xws li kev ua haujlwm logic, kev tswj xyuas ib ntus, sijhawm, suav thiab lej lej, thiab tswj ntau hom tshuab lossis cov txheej txheem tsim khoom los ntawm digital lossis analog input / output. Programmable logic maub los rau lub hauv paus ntsiab lus ntawm kev yooj yim rau kev koom ua ke nrog kev tswj hwm kev lag luam thiab yooj yim los nthuav nws txoj haujlwm. "
Xyoo 1968, General Motors ntawm Tebchaws Meskas tau tshaj tawm cov npe nrov "General Kaum" kev sib tw, uas kuj yog cov yam ntxwv ntawm PLC tam sim no:
1. Cov programming yog yooj yim, thiab cov kev pab cuam tuaj yeem hloov kho ntawm qhov chaw;
2. Kev saib xyuas yooj yim thiab qauv qauv;
3. Kev ntseeg siab yog siab dua li ntawm cov khoom siv relay tswj;
4. Lub ntim me dua li cov khoom siv relay tswj;
5. Cov ntaub ntawv tuaj yeem xa ncaj qha mus rau lub computer;
6. Tus nqi tuaj yeem sib tw nrog cov khoom siv relay tswj;
7. Cov tswv yim tuaj yeem yog AC 115V;
8. Cov zis yog AC 115V, siab tshaj 2A, uas tuaj yeem tsav ncaj qha solenoid li qub, contactors, thiab lwm yam;
9. Thaum nthuav dav, cov txheej txheem qub tsuas yog xav tau kev hloov me me xwb;
10. Tus neeg siv qhov kev pab cuam nco tau nthuav dav.
Xyoo 1978, NEMA txhais cov programmable controller li:
Programmable controller yog ib qho khoom siv hluav taws xob uas ua haujlwm digitally. Nws siv lub cim xeeb programmable los khaws cov lus qhia, ua haujlwm xws li logic, sib lawv liag, sijhawm, suav, thiab lej, thiab tswj nws los ntawm digital lossis analog input thiab output modules. Ntau yam kev siv tshuab lossis cov txheej txheem ua haujlwm.