| 摘要 |
PURPOSE:To prevent malfunctions of a monitor circuit, by detecting that either one of plural input signals continues longer than a fixed time to store it in a corresponding memory circuit and inhibiting the input of the corresponding input signal with the output of the memory circuit. CONSTITUTION:For instance, a relay circuit Si among those circuits S1-Sn has a malfunction and delivers signals continuously. In such a case, an inhibiting circuit 5-i opens a gate in its initial state. Then an OR circuit 1 has an output of H, and a timer 2 has an output of H when the set time elapses. At the same time, an AND circuit 3-i also has an output of H and a storage circuit 4-i maintains an output of H. The circuit 5-i closes the gate to inhibit the input of a signal Si to the timer circuit 2 at a moment when the memory 4-i delivers a level H. This can prevent a mistake that is caused when another relay has a normal operation while either one of the relay circuits has a fault. Furthermore the faulty relay Si is detected by an output Ki of the memory 4-i. |
