Masiku ano, PLC imatha kulandira ma encoder ndi ma sensor opanda ma amplifier, ndiye zosangalatsa za "gwero" ndi "kukhetsa" ndi chiyani? Kutuluka kwa PLC kokha ndi komwe kumakhala ndi malingaliro a "gwero" ndi "kutayikira".

M'malo mwake, kupatula ku Japan PLC, sikofunikira kuti ma PLC ena agwiritse ntchito mawu achidule monga "gwero" ndi "kukhetsa", koma PNP ndi NPN zitha kugwiritsidwa ntchito mwachindunji.

PNP ndi mzere wa anthu otsika kwambiri, ndipo NPN ndi mzere wa anthu okwera kwambiri. Malingana ngati kugwirizana kumeneku kuli kolondola, zikuwoneka kuti ziribe kanthu ngati malingaliro a "gwero" ndi "kukhetsa" asinthidwa. Komabe, lingaliro lina la "positive logic ndi negative logic" ndilolakwika, zomwe zingapangitse kuti chizindikirocho chitembenuzidwe.

Malingaliro abwino ndi malingaliro olakwika

M'mabwalo amtundu wa PNP, cholumikizira wamba chamagetsi ndi ma siginecha ali pamlingo wotsika wa 0V. Kulowetsako kukakhala pamlingo wochepa, palibe kusiyana kwamagetsi ndi cholumikizira wamba, chifukwa chake palibe kutulutsa kwamasinthidwe okulitsa (kuchuluka kwa digito ndi 0). Pokhapokha pamene kulowetsako kuli pamlingo wapamwamba, pali kusiyana kwa magetsi ndi malo ogwiritsira ntchito wamba ndipo chizindikiro chosinthira chokulitsa chimatuluka pamlingo wapamwamba. Njira ya digito iyi (chiwerengero cha digito ndi 1) chomwe chimakhala chothandiza pamene chizindikirocho chili pamlingo wapamwamba chimatchedwa PNP positive logic.

Mu dera la NPN, malo ogwiritsira ntchito magetsi ndi chizindikiro ali pamtunda wapamwamba (khalidwe la dera la amplifier). Kulowetsako kukakhala pamlingo wapamwamba, palibe kusiyana kwamagetsi pakati pa zolowetsa ndi zotulutsa, kotero palibe kusintha kwa siginecha (kuchuluka kwa digito ndi 0). Pokhapokha pamene cholowetsacho chili pamtunda wochepa (kupanga funnel), pali kusintha kwa chizindikiro, ndipo chizindikiro ichi ndi chogwira mtima (chiwerengero cha digito ndi 1) pamlingo wochepa, womwe umatchedwa NPN negative logic.