| 摘要 |
PROBLEM TO BE SOLVED: To provide a photoelectric sensor capable of inhibiting the influence of a disturbance noise or disturbance light, capable of setting an optimum threshold value for accurately detecting various objects respectively even at the time of detecting the various objects. SOLUTION: A fluctuation band P within a unit time T is compared sequentially with a stable width L, when the fluctuation band P≤stable width L, the light receiving level is stored as a 1st stable level Z1. When the light receiving level reduces with the fluctuation width P over the stable width L, and again becomes flat, the mean value Q within a unit time is stored as a 2nd stable level Z2, and their medium level is a temporary threshold value X. Among of successively obtained stable levels Zn, two nearest levels Z5, Z6 to the temporary threshold value X are selected, a normal threshold Y is set at the medium level of the Z5, and Z6. This normal threshold value Y discriminates light receiving level with a margin for every object W passing by. COPYRIGHT: (C)2004,JPO |
