| 摘要 |
PURPOSE:To provide open and close state monitoring means which is adapted to input no drive signal to a relay driving circuit by discriminating the case where a relay contact point is deposited, or a transistor of the relay driving circuit is broken. CONSTITUTION:When electromagnetic force is generated at a node A before a square wave is output from an interface 18, the first relay contact point 2 is deposited to be close or a transistor 8 is broken to be put in the conducting state. At this time, a square wave and a relay drive signal are not output from the interface 18. In the case where the second relay contact point 3 is deposited or the transistor 13 is broken, similarly outputting of a square wave from the interface is stopped. |
