| 摘要 |
PURPOSE: To indicate to an operator that an external earth connecting terminal is damaged by connecting a switching element to a line for controlling a warning device, connecting another connecting terminal of the switching element to another external earth connecting terminal, and blocking the switching element when the external connecting terminal of control equipment is not damaged. CONSTITUTION: In order to monitor whether or not the external earth connecting terminal 7 of control device equipment 4 is undamaged, a switching element S1 is inserted between a line 4c for controlling a warning device 1 and another external earth connecting terminal 12. In the event that the external earth connecting terminal 7 is damaged, the switching element S1 detects this and switches the earth connecting terminal 12 to the line 4c. When the external earth connecting terminal 7 is not damaged, the switching element S1 is blocked. Thus, the malfunction and absence of the external earth connecting terminal 7 can be indicated to an operator. |
