| 摘要 |
PROBLEM TO BE SOLVED: To accurately achieve error judgement by rectifying and shaping a commercial power supply into a rectangular wave, and detecting building-up of the rectangular wave, and further using the building-up signal as a source input signal upon clocking and simultaneously performing instantaneous power interruption detection. SOLUTION: A commercial power supply 101 is connected with rectifier means 102 and is rectified, an output of which is connected with waveform shaping means 103 and is shaped into a rectangular wave. An output of the rectangular wave is converted by a building-up detection means 104 into a rectangular building-up signal, with which a signal clocking means 107 for clocking time is driven, and which signal is inputted into a building-up signal interval detection means 105 for measuring an interval of the building-up signal, with which interval instantaneous power interruption is judged by an instantaneous power interruption judgement means 106. Hereby, a trouble of a power supply current measuring circuit is not judged upon instantaneous power interruption so that possibility of error of the trouble judgement is reduced. |
