▁access ▁control ▁system ▁determ ines ▁the ▁user ▁is ▁author ized ▁to ▁go ▁through . ▁A ▁trigger ▁from ▁any ▁of ▁the ▁above ▁requests ▁that ▁the ▁door ▁be ▁opened ▁( or ▁re open ed ▁if ▁it ▁was ▁closing ). ▁The ▁operator ▁will ▁he ed ▁hat ▁requests ▁only ▁after ▁it ▁is ▁able ▁to ▁do ▁so ▁safely ▁for ▁any ▁other ▁users ▁in ▁the ▁area . ▁ ▁Saf ety ▁sens ors ▁ ▁A ▁door ▁operator ▁may ▁use ▁sens ors ▁to ▁prevent ▁the ▁door ▁from ▁coming ▁into ▁contact ▁with ▁a ▁user . ▁ ▁Full ▁Energy ▁operators ▁require ▁at ▁least ▁ 3 ▁sens ors . ▁Low - energy ▁operators ▁are ▁not ▁required ▁to ▁have ▁safety ▁sens ors , ▁as ▁the ▁door ▁is ▁allowed ▁to ▁come ▁in ▁contact ▁with ▁a ▁user , ▁given ▁that ▁the ▁kin etic ▁energy ▁of ▁the ▁moving ▁door ▁is ▁limited ▁by ▁the ▁reduced ▁moving ▁speed . ▁ ▁Histor ically , ▁sens ors ▁have ▁been ▁simply ▁floor ▁m ats ▁that ▁sense ▁the ▁weight ▁of ▁a ▁user , ▁one ▁in ▁the ▁area ▁immediately ▁in ▁front ▁of ▁the ▁door ▁( the ▁approach ▁side ) ▁and ▁one ▁in ▁the ▁area ▁behind ▁it ▁( the ▁swing ▁side ). ▁The ▁approach ▁side ▁mat ▁is ▁often ▁used ▁as ▁a ▁trigger ▁sensor . ▁The ▁swing ▁side ▁mat ▁prevents ▁the ▁door ▁from ▁starting ▁to ▁open ▁as ▁long ▁as ▁some ▁other ▁person ▁is ▁detected ▁in ▁the ▁swing ▁area ; ▁once ▁the ▁door ▁starts ▁opening , ▁this ▁mat ▁is ▁ignored , ▁as ▁it ▁will ▁sense ▁the ▁user ▁going ▁through . ▁ ▁Today , ▁inf ra red ▁safety ▁sens