Purpose
This guide explains how to connect a door sensor (door contact) to a ButterflyMX 2 Door Controller using the Door SNS input, and how the system uses this input for door monitoring and alerts.
What is a Door Sensor?
A door sensor (door contact) is a device that detects whether a door is open or closed.
It consists of:
- A magnet (mounted on the door)
- A contact switch (mounted on the frame)
NO Configuration (Normally Open):
- Door closed → circuit is OPEN
- Door open → circuit CLOSES
This change in state is used by the controller to detect door activity.
What is it Used For?
Door sensors provide real-time door status monitoring and enable:
- Door open/closed detection
- Door held open alerts
- Forced entry detection
Prerequisites
- ButterflyMX 2 Door Controller installed and powered
- Door lock hardware installed and functional
- Access to Door SNS terminals
- Door sensor (NO dry contact)
- Low-voltage wiring (18–22 AWG recommended)
Important Warning |
Wiring Summary (NO Configuration)
| Door Sensor | 2-Door Controller Terminal |
| COM | Door SNS |
| NO | Door SNS |
Door Sensor COM → Controller Door SNS
Door Sensor NO → Controller Door SNS
Procedure
- Locate Door SNS terminal on the controller.
- Prepare wiring using 18–22 AWG cable.
- Connect sensor COM to controller Door SNS.
- Connect sensor NO to controller Door SNS.
- Mount the sensor on the frame and the magnet on the door.
- Ensure proper alignment when the door is closed.
- Secure all connections.
- Test door open/close detection.
How ButterflyMX Uses Door Sensor
1. Door Held Open Alert:
If the door remains open longer than a configured time (e.g., XX seconds), the system triggers a Door Held Open alert.
Alerts can be delivered via email notification or SMS/text message.
2. Forced Entry Detection:
If the door opens without a valid unlock event, the system detects unauthorized or forced entry.
Alerts can be delivered via email notification or SMS/text message.