| 摘要 |
PURPOSE:To make it possible to decide a fault surely with a comparatively simple constitution, by causing the CPU to diagnose the fault on a basis of change of the normal operation signal of the CPU and change of the transmission and receiving signal of the control station. CONSTITUTION:Normal operation signal 6 of control station 3 is generated by using input signal 7 obtained from communication line 1, output signal 8 to communication line 1, and normal operation signal 16 from CPU10 as the input in fault detecting circuit 5. This signal 6 operates the contact of relay 4, and at the normalcy time, relay 4 is so operated that station 3 may be included in communication line 1. Signal 16 is input to multivibrator 50; and if the signal is changed in the time section determined by the time constant of this circuit, output signal 17 is held in the 1 state. This signal is input to the IRQ terminal as interrupt signal 18 for CPU10. When this interrupt is repeated continuously up to a prescribed frequency, it is confirmed whether an abnormal endless loop is generated in the program or not, and CPU10 is stopped if anomaly is detected. |
