| 摘要 |
PROBLEM TO BE SOLVED: To detect a power stoppage via the adroit utilization of the output of a commercial frequency detecting circuit and to quickly store prescribed parameters at the time of the power stoppage by checking whether the cycle of a pulse signal coincides with the prescribed cycle range or not, judging that the feed of the commercial power supply is normal when they coincide, judging that the power stoppage occurs when they do not coincide, and storing the prescribed parameters. SOLUTION: The full-wave rectified output of a rectifying circuit 2 is fed to a commercial frequency detecting circuit 6, and the collector voltage of a transistor Q2 has a wave-form repeated at the cycle (T/2) which is a half of that of a power supply 1. The output of a photo-coupler PC2 becomes a voltage wave-form (rectangular wave), and it is fed to a CPU 7 as an interrupt signal. The CPU 7 sets the dedicated flag to '1' each time it receives an interrupt. It is judged that power is normally fed when the flag is set to '1', and it is judged that a power stoppage occurs when the flag is set to '0'. If the state that the flag is set to '1' successively occurs (m) times, a parameter storage program is executed to store prescribed parameters.
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