| 摘要 |
PROBLEM TO BE SOLVED: To solve the problem of a conventional digital protective relay device, where CPU processing failure is monitored by a watch dog timer, which cannot identify possible causes of failure, or cannot return even some failure due to transient factor to a proper state. SOLUTION: A wait monitoring circuit 5 returns a waiting signal once, when the WAIT signal of a CPU2 continues for over a fixed period, thereby returning transient failure to a proper state. For identifying the possible causes of some failure, this device includes not only a means of the returning but also a waiting continuance storing circuit, storing holding of the state of a read/write signal WR and continuation of the waiting state with an interrupt into the CPU and a waiting factor storing circuit for storing the control output of the CPU during interrupt as a waiting factor. |
