| 摘要 |
PURPOSE:To secure the safety for the controlled apparatus by detecting the abnormality of the input signal of the timer counter and thus stopping the operation at the load driving part. CONSTITUTION:The prescribed voltage is secured (1) by the commercial AC current; the waveform shaping (2) is given to the output; and the frequencies of the output to be higher than the threshold level are counted and converted (4) into the time to be supplied to comparison arithmetic part 6. Then the output is produced at part 6 in accordance with the desired time given from setting part 7 in order to drive power driving part 5. In this case, the waveform-shaped output is supplied also to fault detection part 3, and the output is produced at part 3 after a fixed time since the initial state to stop the operation at part 5, 6 and other parts. |
