| 摘要 |
PURPOSE:To detect the breaking and recovery of a circuit with extremely high accuracy by initializing a counter when a light signal is present. CONSTITUTION:The light signal SO is converted into an electric signal S1, which is applied to an inverter 6. Consequently, the output of the inverter 6 rises to ''1'' when the light signal is received and falls to ''0'' when not, and every time the signal ''1'' is inputted, the counter 7 is initialized. On the other hand, while the output signal S7 of the counter 7 is ''0'', a clock from a clock pulse generator 8 is applied to the input terminal K of the counter 7. Therefore, when the light signal s present, the counter 7 is reset immediately, but when not, it outputs the signal ''1'' continuously. For this purpose, the counted value of the counter 7 is preset properly to detect the breaking of a circuit accurately in the shortest time. |
