The function and principle of door sensor alarm, the application of door alarm contact switch in access control system
door magnetic contact is a small sensor used to detect whether the door is closed, there are a lot of electric locks is with door magnetic function, if the access control system need use magnetic contact , it is best to purchase electric lock which is with door magnetic function (door status feedback Function). If the electric lock does not have the door with the magnetic function, you can choose the door magnetism, Mencius size slightly larger than a dollar coins, the price in a few dollars or so.
This is a common on the market of a concealed door magnetic, without a wire inside the end of the magnet, with low-end internal possession of the reed switch and other components, when the magnet close to the wire output closed signal, when the magnet Away from the two wires output open signal. One end without wires is mounted on the top of the door and one end of the wire is mounted on the door frame. When the door is closed, the ends are overlapping. There are some Mencius on the market is a square, suitable for the occasion, for doors and windows.
Which features the door can be used for access control system:
When the door is closed, the closed signal is output (measuring the resistance with a multimeter is 0) and the open signal is input when the door is open. (With a multimeter to measure the resistance infinity)
Note: 90% of the market is such a feature of the Menci, there are a small amount of door magnetic characteristics of the opposite, or closed signal and open signal output (three lines, one is public, the other two with the public line output open and Close the signal, with the time, choose one of the pair, the characteristics of an idle). Some of the electric lock of the door is also the case, such as: 5 line plug (2 is the power supply, 3 is the door signal line), 8-wire plug (not only with the door output, and with the lock position status output ), The unused line can be idle.
The main role of Menci in the access control system is the following:
In real-time monitoring of the software, you can see whether the current state of each door is open or closed.
Can be used with the access controller to enable the door to be illegally entered (no credit card or press the button to operate the law, and the door was opened, such as kick open or pry open) alarm.
Can be used with the access controller to enable the door for a long time without closing the alarm. Wait
Note: If you do not need these features access control system, you can not access the door. If you need these functions, the door will be connected to the controller's door input point (such as S1 GND), do not distinguish between positive and negative. If a large multi-door access control system, only a few doors used to the door of these functions, the other Menci input point (such as S1 GND) with a short circuit to avoid false alarm signal