What is used to monitor the opening and closing state of fire doors?

Fire door magnetic switch.

The magnetic switch of fire door is a device used to monitor the opening and closing state of fire door. It consists of magnetic materials and contactors. When the fire door is closed, the door magnetic switch will be automatically adsorbed on the door frame, and the contactor will be closed, indicating that the fire door has been closed. When the fire door is opened, the door magnetic switch will be separated from the door frame and the contactor will be disconnected, indicating that the fire door has been opened.

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