Lesson 1.6: Door Sensors (Reed Switches)

⚡ The Logic (Mermaid)

flowchart LR
    MAGNET["Magnet
on Door"] -. "proximity" .- SENSOR["Reed Switch
on Frame"]
    subgraph DINPUT["Door Input Terminal"]
        direction TB
        INPUT["Reed Input"]
        ZV["0V"]
    end
    SENSOR ---|"Wire"| INPUT
    SENSOR ---|"Wire"| ZV

Hardware Landmark: Door Sensor (Reed Switch)

!300
Above: A heavy-duty surface-mount reed switch and magnet pair.

🧠 The Concept

A Reed Switch (or Door Contact) tells the system if the door is physically Open or Closed. This is used for "Door Ajar" (Door held open too long) and "Door Forced" (Door opened without a valid badge) alarms.

🛠️ Hands-on Steps

Alignment: The magnet (on the door) and the sensor (on the frame) must be perfectly aligned.
Gap Distance: Ensure the gap is within the sensor's operating range (usually <15mm for standard contacts).
Integriti Wiring: Wire to the "DOTL" (Door Open Too Long) input on your Access Module.

⬅️ Previous | Next Lesson ➡️