摘要 |
First determination means 16 determines whether a deviation exceeds a threshold value, measurement means 17 measures the period in which the deviation exceeds the threshold value in accordance with the determination result, second determination means determines whether the period in which the deviation exceeds the threshold value continues for a certain period or more in accordance with the measurement result, third determination means 19 determines whether the absolute value of the deviation decreases, and trouble determination means 2 determines that a trouble occurs when the period in which the deviation exceeds the threshold value continues for a certain period or more and the absolute value of the deviation does not decrease.
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