| 摘要 |
<p>PURPOSE:To remove misdiagnosis or misswitching by changing conditions and detecting a sudden failure case of a controller and its sow failure case in normal service. CONSTITUTION:Comparing/deciding devices 21, 22 compare and decide the absolute value of a difference between the output of a normal system controller and that of a waiting system controller with deviation set values 1, 2 and output deceding signals s31, s32 to an OR circuit 41 through timers 31, 32. A sudden failure is detected by a 1st condition setting up the set time T1 of the timer 31 to a short value and the deviation set value epsilon1 to a large value and a slow failure is detected by a 2nd condition setting up the deviation set value epsilon2 to a small value and the set time T2 of the timer 32 to a long value. Consequently, the failure of the controller over a wide range from the sudden failure to the slow failure can be quickly detected without sharply disturbing an object to be controlled and misdiagnosis or misswitching can be reduced.</p> |
