| 摘要 |
PROBLEM TO BE SOLVED: To reduce the risk that a fire receiver will suffer a circuit failure due to external noise generation such as thunder, by connecting an otherwise disconnected ground detection circuit to a ground only for a minimum necessary time of ground detection. SOLUTION: The fire receiver, which has the ground detection circuit for detecting grounding of a C line or Ln line connecting fire sensors, is provided with a ground switching means disposed between the ground detection circuit and a ground to disconnect the ground detection circuit and the ground normally and connect them periodically. The ground detection circuit thus performs periodic ground detection. COPYRIGHT: (C)2008,JPO&INPIT
|
