| 摘要 |
PURPOSE:To monitor a failure in a counter circuit and a logical circuit with very high probability, by monitoring a counting output signal of the counter circuit and the operation of the logical circuit with a monitor circuit. CONSTITUTION:A monitor circuit 4 inputs a count output signal D of a counter circuit 3 and discriminates that the operation of the circuit 3, a timer circuit 2 and a logical circuit 1 is correct if the count value (i) is within a prescribed range. Next, the circuit 4 executes increment of the circuit 3 by a number subtracting the count value (i) from the count up value (n) of the circuit 3 and checks if the counting output signal D from the circuit 3 is n. If not n, the circuit 4 judges it as a failure in the circuit 3 and compulsively outputs external output information I of an output circuit 5 to predetermined state. If the counting value (i) of the circuit 3 is not within the prescribed range, it is judged as a failure in the circuit 1, the information I is compulsively outputted to the predetermined state and the circuit is not started. |
