| 摘要 |
PROBLEM TO BE SOLVED: To detect the existence of abnormality of a program about an external interruption terminal and to prevent normal control from being stopped by outputting a check signal from a CPU and deciding the existence of abnormality of the external interruption terminal or a program about the external interruption terminal. SOLUTION: When the existence of abnormality is decided, a switching signal is outputted from an output terminal (c) of a CPU (e), a switching means (g) is switched to a check signal inputting side, and then, a check signal is outputted from an output terminal (d) of the CPU (e). An external interruption terminal abnormality detecting means (h) decides whether or not an external interruption function is normal and decides as abnormal if decision as not normal continues a prescribed time or more. This eliminates the danger of continuing control that can not detect a failure and preventing normal control. Also, it is possible to prevent erroneous detection by performing abnormality decision after abnormal detection continues the prescribed time. |
