| 摘要 |
<p>PURPOSE:To detect the abnormal working of a control circuit effectively and completely by using the normal end signal given from the control circuit to start a timer. CONSTITUTION:A controlled system is controlled by a control circuit 1 at a prescribed cycle and a signal S6 is delivered to a timer 2 when said control is through normally. Thus counters 21-23 are set to 0. The timer 2 counts the clock pulses S1 produced for each prescribed period of time. The signal S6 is delivered continuously to the timer 2 as long as the circuit 1 is working normally and therefore the timer 2 is never set at the prescribed set time. However no signal S6 is delivered if the circuit 1 has the abnormality and therefore the timer 2 is set at the prescribed value. A detecting circuit 3 detects this and delivers the abnormality detecting signal S5 to a signal generating circuit 4. The circuit 4 delivers the signal S7 to the circuit 1 to start the interruption processing to the circuit 1. Then the circuit 1 interrupts the abnormal working or changes the abnormal working to the normal working.</p> |
