| 摘要 |
PURPOSE:To prevent the generation of misalarming by outputting an abnormality alarm when the level of a penetrated ultrasonic wave is smaller than the reference value continuously for a specific time length. CONSTITUTION:In case of abnormality in an equipment, the output of a driving circuit 5 lowers and when penetration signals become smaller than the reference level E continuously, output of a comparator 14 moves to ''0'', bringing the Q output of DFF15 to the level ''L''. Then, the terminal D of DFF16 goes to the level ''L'' and the Q output of the DFF16 turns to the level ''L'' at the rising of a clock signal to the subsequent DFF16. As a result, the Q output of the DFF16 moves to the level ''H'' and a warning tone is given from a speaker 12 through an OR circuit 10 and an alarm driving circuit 11. |
