| 摘要 |
PURPOSE:To detect a fault of a controlling system precisely by preparing a reset requesting flag to control many tasks and finding AND with data indicating the operation status in each task to reset a watch dog timer. CONSTITUTION:A task to be used in a series processing has a self-logical watch dog timer No. and a watch dog timer reset pattern to call a subroutine WDT. The subroutine WDT turns a bit area corresponding to a reset request flat 1 corresponding to the timer No. to ''1''. If a fault is generated in a controlling system and the task is not executed, the bit area corresponding to the flag 1 is still kept at ''0''. If the timer reset pattern coincides with the contents of the reset requesting flag 1 at the completion of a series task processing, the watch dog timer is reset. Consequently, the fault of the controlling system can be precisely detected even if an important function is alloted to plural tasks. |
