| 摘要 |
PURPOSE:To make it possible to prevent efficiently erroneous control, by monitoring periodically whether control command logic, input point information of the input device, and output point information of the output device are present or not respectively. CONSTITUTION:In computer 1, three elements, namely, control command logic, input point 12 of relay 6 in the input device, and output point 11 of relay 6 in the output device are monitored. If one or two of these three elements do not exist, anomaly is decided, and contact 7A of relay 7 for erroneous control prevention is turned off, and contact 8A of relay 8 for anomaly detection is closed to display anomaly of the input device, the output device, and so on. Since contact 7A is turned off for anomaly in this manner, operation commands (electric power applying) to control device 5 are not issued independently of the switching state of contact 6B of relay 6. As a result, erroneous control for anomaly is prevented. Thus, erroneous control can be prevented efficiently. |
