| 摘要 |
PURPOSE:To completely eliminate erroneous operation and to cope simply with different workpiece through changes in set value to a discriminating circuit, by differentiating an output signal which is obtained by contactlessly detecting a distance to a workpiece, so as to discriminate whether the workpiece has been processed or not. CONSTITUTION:When a workpiece 13 enters in a detected effective area facing a sensor 15, a limit switch 18 is turned on so as to energize a differential circuit 20 and a discriminating circuit 21. If the workpiece 13 is not yet processed, an output from the sensor 15 gives a smooth curve while if it has been processed, and output gives a curve having undulations. When these outputs are delivered to the circuit 20, the circuit 20 delivers a low level output if the workpiece is not yet processed, but it delivers a high level output if the workpiece has been processed. These outputs are delivered to the discriminating circuit 21 which delivers a signal indicating an unprocessed workpiece if the output is below a set value but delivers a signal indicating a processed workpiece if the output exceeds the set value, thereby it is possible to discriminate whether the workpiece 13 has been processed or not. |
