| 摘要 |
PURPOSE:To reduce accidents due to the disconnection of a power source by incorporating a relay switch which is driven when the power source is turned on, a relay swich which sends a power-off signal to a CPU, and a relay switch which receives a power-off permit signal in the electric power unit. CONSTITUTION:When a power switch S6 is closed, a power source control part 5 closes a main S3 to supply electric power to a CPU11 and control parts 12-14 through a stabilized power source 4, thereby starting operation. Then when the S6 is closed, the control part 5 sends a power-off signal to the CPU11 through a signal line 7. The CPU11 makes the control parts 12-14 cope with the disconnection of the power source and sends out the power-off permit signal to the control part 5 through a signal line 8 after the operation of the control parts. The control part 5 closes the S3 on receiving the power-off permit signal. The control part 5 is provided with the relay switch 20 which controls the opening and closing of the S3, relay switch 22 which sends the power-off signal to the CPU11, and relay switch 21 which receives the power-off permit signal, reducing accidents due to the disconnection of the power source. |
