Kule mihla, i-PLC inokufumana i-encoder kunye ne-sensor signals ngaphandle kweamplifier, ngoko yintoni eyonwabisayo "yomthombo" kunye "nokukhupha"? Kuphela yimveliso ye-PLC eya kuba neekhonsepthi "zomthombo" kunye "nokuvuza".

Enyanisweni, ngaphandle kwe-PLC yaseJapan, akuyomfuneko ukuba ezinye ii-PLC zisebenzise izishunqulelo ezifana ne-"source" kunye "ne-drain", kodwa i-PNP kunye ne-NPN inokusetyenziswa ngokuthe ngqo.

I-PNP ngumgca we-low-voltage yoluntu, kwaye i-NPN ngumgca woluntu ophezulu. Lo gama nje olu xhulumaniso luchanekile, kubonakala ngathi akunamsebenzi ukuba iikhonsepthi "zomthombo" kunye "ne-drain" ziguqulwa. Nangona kunjalo, enye ingcamango "ingqiqo echanekileyo kunye nengqiqo engalunganga" nayo ayilunganga, eya kubangela ukuba uphawu luguqulwe.

Ingqiqo ephilileyo kunye nengqiqo engalunganga

Kwiisekethe zohlobo lwe-PNP, i-terminal eqhelekileyo yonikezelo lwamandla kunye nesignali ikwizinga eliphantsi le-0V. Xa igalelo likwinqanaba eliphantsi, akukho ntlukwano ye-voltage kunye ne-terminal eqhelekileyo, ngoko akukho mveliso yesignali yokutshintsha eyandisiweyo (ubuninzi bedijithali yi-0). Kuphela xa igalelo likwinqanaba eliphezulu, kukho ukuhluka kwe-voltage kunye ne-terminal eqhelekileyo kunye ne-amplified switching signal iphuma kwizinga eliphezulu. Le ndlela yedijithali (ubuninzi bedijithali yi-1) esebenzayo xa umqondiso ukwizinga eliphezulu libizwa ngokuba yi-PNP ye-positive logic.

Kwisekethe ye-NPN, i-terminal eqhelekileyo yonikezelo lwamandla kunye nesignali ikwizinga eliphezulu (uphawu lwale sekethi ye-amplifier). Xa igalelo likwinqanaba eliphezulu, akukho ntlukwano ye-voltage phakathi kwegalelo kunye nemveliso, ngoko ke akukho mveliso yesignali yokutshintsha (ubuninzi bedijithali yi-0). Kuphela xa igalelo likwinqanaba eliphantsi (ukwenza i-funnel), kukho ukukhutshwa kwesignali yokutshintsha, kwaye lo mqondiso uyasebenza (ubuninzi bedijithali yi-1) imodi yedijithali kwinqanaba eliphantsi, elibizwa ngokuba yi-NPN logic negative.