| 摘要 |
<p>PURPOSE:To eliminate an artificial error, and also, to very easily set the reference position by detecting the reference position at the time of counting a wafer by a sensor provided in a position known in advance. CONSTITUTION:By driving a cassette stocker 7 and an ascending/descending motion mechanism part, a wafer piece number counter 10 is moved to a shelf to be counted. An ascending/descending table 18 is allowed to ascend or descend, and a receiving part 16a of a reference position sensor 16 is allowed to pass through a confronting position of a transmitting part 16b. The receiving signal level maximum value is decided by a receiving signal processing part 26, and in a counting part 25, from a position of the ascending/descending table 18 by the receiving signal level maximum value, a reference position is discriminated. A result of discrimination is inputted to a motor control part 24 and a main control part 22 and the reference position is set. Subsequently, counting of a wafer is started, and by a sensor 15, the water is detected, and a distance to the reference position, etc., are measured, and whether the wafer exists or not, and its omission are discriminated. Its result is recorded by a main control part 22, and also, displayed on an operating part 28.</p> |
