| 摘要 |
<p>PURPOSE: To prevent electric power from being consumed when a board unit which is not always used is not used by enabling the power source for board units that are connected to a system bus to be turned ON and OFF by the board units. CONSTITUTION: To use an I/O 56, for example, a CPU board unit outside the figure on the system bus 1 sets command data for turning on a relay 58 set in the command register 571 for power source control in the system bus interface part 57 of a board unit 5 for I/O control. Consequently, the power source 581 on the system bus which is always available is supplied to the main body part of the board unit 5 within the dotted-line frame as a power source 582 for a main board through the relay 58 and I/O control operation is started.</p> |
