Niaj hnub no, PLC tuaj yeem tau txais cov cim encoder thiab sensor tsis muaj amplifier, yog li kev lom zem ntawm "qhov" thiab "drain" yog dab tsi? Tsuas yog cov zis ntawm PLC yuav muaj cov ntsiab lus ntawm "qhov chaw" thiab "tawg".

Qhov tseeb, tshwj tsis yog Japanese PLC, nws tsis tsim nyog rau lwm PLCs siv cov ntawv luv xws li "qhov" thiab "drain", tab sis PNP thiab NPN tuaj yeem siv ncaj qha.

PNP yog cov kab hluav taws xob tsawg, thiab NPN yog cov kab hluav taws xob siab. Tsuav qhov kev sib txuas no yog qhov tseeb, nws zoo li nws tsis muaj teeb meem yog tias cov ntsiab lus ntawm "qhov chaw" thiab "drain" yog thim rov qab. Txawm li cas los xij, lwm lub tswv yim "zoo logic thiab tsis zoo logic" kuj yog qhov tsis ncaj ncees lawm, uas yuav ua rau lub teeb liab rov qab.

Zoo logic thiab tsis zoo logic

Hauv PNP-hom circuits, qhov dav dav dav dav ntawm lub zog hluav taws xob thiab teeb liab yog nyob rau theem qis ntawm 0V. Thaum cov tswv yim nyob rau theem qis, tsis muaj qhov sib txawv ntawm qhov sib txawv nrog lub davhlau ya nyob twg, yog li tsis muaj qhov hloov pauv hloov lub teeb liab tawm (cov lej digital yog 0). Tsuas yog thaum cov tswv yim nyob rau theem siab, muaj qhov sib txawv ntawm qhov sib txawv nrog cov khoom siv dav dav thiab cov teeb liab hloov pauv amplified yog cov zis ntawm qib siab. Hom digital no (digital kom muaj nuj nqis yog 1) uas siv tau thaum lub teeb liab nyob rau theem siab yog hu ua PNP zoo logic.

Nyob rau hauv lub NPN Circuit Court, qhov dav dav dav ntawm lub hwj huam mov thiab lub teeb liab yog nyob rau theem siab (tus yam ntxwv ntawm lub amplifier Circuit Court). Thaum cov tswv yim nyob rau theem siab, tsis muaj qhov sib txawv ntawm qhov kev tawm tswv yim thiab cov zis, yog li tsis muaj kev hloov cov teeb liab tso zis (cov lej digital yog 0). Tsuas yog thaum lub tswv yim yog nyob rau theem qis (tsim ib qho funnel), muaj qhov hloov cov teeb liab tso zis, thiab cov teeb liab no yog qhov ua tau zoo (cov lej yog 1) hom digital ntawm qib qis, uas yog hu ua NPN tsis zoo logic.