Interference compensation optically synchronized safety detection system for elevator sliding doors

Abstract

A method for detecting interference energy in a sliding door safety system includes the steps of disposing at least one emitter along a first vertical surface, disposing at least one receiver corresponding to the at least one emitter along a second vertical surface, activating the at least one receiver, activating the at least one emitter to emit an energy beam that includes a modulated square wave of a predetermined frequency, sampling an energy intensity received by the activated at least one receiver a predetermined number of times recording each time a received energy intensity to form a plurality of recorded energy intensities, selecting the lowest magnitude one of the plurality of recorded energy intensities to form a lowest recorded energy intensity, comparing the lowest recorded energy intensity to a threshold value and determining a source of the energy intensity to be external when the lowest recorded energy intensity is less than the threshold value.

Dependencies are inferred from the claim text.