| 摘要 |
PURPOSE:To suppress the damage of runaway at the minimum level, by adding a processor runaway detection circuit that detects the runaway of a processor, restoring a relay circuit by the output signal of the detection circuit, and returning a state to the one before the processor starts to run away. CONSTITUTION:It is detected whether a processor 12 runs away or not by adding a processor runaway detecting circuit 50 on a processor 12, and if the processor is running away, a relay 10 ie restored to a normal state. One example is as follow. When a runaway detecting program is executed with a constant cycle, and the program is executed normally, a mark is put on a register provided within the processor runaway detection circuit 50, and the time interval of the generation of a mark signal is monitored by a timer. When no mark signal arrives within a certain regulated time interval, it is decided that the runaway of the processor 12 is generated, then the relay 10 is restored. Also, in a case that the processor 12 has a system to output a pulse on a fetch cycle, it is possible to detect the runaway by monitoring the output pulse. |
