The opening detectors

There are a number of devices available for monitoring of the opening of doors, which differ primarily in their mechanical design and the purpose. Some recommended types are described below.

When installing the detectors (magnetic contacts), you must follow a few guidelines:

• The protected windows and doors must have an exacttly defined position when they are closed (e.g. their position must not be changed by wind, which could to a disconnection of the contact and a false alarm).

• A maximum stated gap (for the switched - idle state) is considered in ideal conditions; any metallic ferromagnetic material in the vicinity of the contact reduces the range (e.g. metal door frames decrease the maximum gap by more than half).

• The contact must be set as exactly as possible to achieve the best possible functionality.

• The part of the contact with the terminal is always installed on the fixed part of the windows or doors (the frame).

• The connection of a 2-wire or a 4-wire contact is illustrated in the following example.