Patent ID: 6803556
Filing Date: 2004-10-12
Classification: G01V

Abstract:
A photoelectric sensor comprising:a light emitting section for emitting light to a detection area; a light receiving section for receiving light from the detection area; an amplification circuit for amplifying an electric signal corresponding to a light receiving amount output from said light receiving section; an A/D converter for converting an output voltage of said amplification circuit into a digital value; and a processing section for controlling light emitting operation of said light emitting section and processing the digital value provided by said A/D converter, wherein said photoelectric sensor has a high-precision mode wherein a light emitting amount of said light emitting section or an amplification ratio of said amplification circuit is made lower than that in a normal mode, whereby said amplification circuit or said A/D converter is made hard to be saturated, and wherein the processing section, in the high-precision mode, causes said light emitting section to perform the light emitting operation a plurality of times successively, adds a plurality of digital values provided by said A/D converter in response to the light emitting operation performed plurality of times, and processes the digital value of the addition result as a detection value corresponding to the light receiving amount.