| 摘要 |
PURPOSE:To prevent operator's sleep from being disturbed, by forcibly stopping a fan in the time zone when he falls asleep and controlling turn-on/off of the fan at a low speed in accordance with the temperature in a board in the time zone of sleep following the time zone. CONSTITUTION:A period (b) from a time T2 to a time T3 at night is the time zone when the operator falls asleep. When a forcibly turning-off command 12 (in the high level) is outputted from a schedule generator 3, a control line 15 is set to the low level, therefore, outputs (control lines 17 and 19) of AND elements 7 and 10 go to the low level, and an operation relay 52 and a low- speed operation relay 42 are inactivated to stop a cooling fan 1, then, the operator can fall asleep because the noise is not generated. A period (c) from the time T3 to a time T1 is the time zone of sleep, and the schedule generator 3 does not output a turning-on command neither the forcibly turning-off command then. Therefore, turn-on/off of the cooling fan is automatically controlled in accordance with the detection temperature of a temperature sensor 4.
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