1. Product Overview
The KERUI D0251 is a wireless magnetic contact sensor designed to detect the opening and closing of doors or windows. It functions as part of a compatible KERUI alarm system, sending an alert signal to the main unit when triggered. This sensor is ideal for enhancing home security by monitoring entry points.
Figure 1: KERUI D0251 wireless door sensor installed on a door.
2. Components
The KERUI D0251 sensor consists of two main parts: an emitter unit and a magnet unit. These units work together to detect changes in proximity.
Figure 2: Emitter and Magnet Units. Ensure triangle marks align during installation.
3. Setup and Installation
Follow these steps to properly install your KERUI D0251 wireless door/window sensor:
- Compatibility Check: Ensure the D0251 sensor is compatible with your KERUI alarm system. It operates on a 433 MHz radio frequency and requires a KERUI base unit to function. It cannot operate independently or with other alarm systems.
- Proximity to Control Unit: Place the sensor within 80 meters (250 feet) line-of-sight of your control unit. This distance may be reduced by barriers such as walls.
- Component Placement: Attach the larger emitter unit to the fixed part of the door or window frame. Attach the smaller magnet unit to the movable part of the door or window.
- Alignment: For correct operation, the emitter and magnet units must be aligned with their triangle marks facing each other. When the door or window is closed, the gap between the two units should be less than 1 cm (0.4 inches).
- Testing Alignment: Before permanent attachment, hold the magnet and emitter in place manually. Close the door or window and observe if the LED indicator on the emitter flashes. A flash confirms proper spacing and alignment.
- Secure Attachment: Use the included double-sided adhesive tape to securely mount both units.
- Battery Installation: The sensor comes with one 23A 12V battery. Ensure it is correctly installed.
Figure 3: Sensor dimensions and alignment guide.
Figure 4: Various installation examples on doors and windows.
4. Operating Instructions
The KERUI D0251 sensor operates by detecting the separation of its two magnetic components.
- Triggering an Alarm: When the door or window is opened, causing the emitter and magnet to separate by more than 1 cm, the sensor will instantly send an alert signal to the paired KERUI alarm host. This triggers the alarm system.
- LED Indicator (Normal Operation): When the door or window is opened, the LED indicator on the emitter unit will flash red for approximately 2 seconds, confirming that a signal has been sent.
- LED Indicator (Low Battery): If the battery is low, the LED indicator will illuminate red and remain lit. This indicates that the battery needs to be replaced to ensure continued proper operation.
Figure 5: Sensor workflow from detection to alarm notification.
5. Maintenance
- Battery Replacement: When the low battery LED indicator is continuously lit red, replace the 23A 12V battery immediately. To replace, carefully open the emitter unit, remove the old battery, and insert a new one, observing polarity.
- Cleaning: Periodically wipe the sensor units with a soft, dry cloth to remove dust and dirt. Do not use abrasive cleaners or solvents.
- Environmental Conditions: Ensure the sensor is not exposed to extreme temperatures or high humidity outside its specified operating range to prevent damage.
6. Troubleshooting
- Sensor Not Triggering Alarm:
- Check battery: Is the low battery indicator on? Replace the battery if necessary.
- Check alignment: Ensure the emitter and magnet units are aligned with their triangle marks and the gap is less than 1 cm when closed.
- Check distance: Verify the sensor is within 80 meters (line-of-sight) of the KERUI alarm host. Reduce distance if there are many obstructions.
- Check pairing: Confirm the sensor is correctly paired with your KERUI alarm system. Refer to your alarm system's manual for pairing instructions.
- False Alarms:
- Ensure the sensor is securely mounted and not subject to vibrations or movement that could cause the units to separate.
- Verify the gap between the units is consistently less than 1 cm when the door/window is closed.
- Incompatibility: This sensor is designed exclusively for KERUI alarm systems operating at 433 MHz. It is not compatible with other brands or frequencies.
7. Specifications
| Feature | Specification |
|---|---|
| Model | D0251 |
| Battery | 1 x 23A 12V (included) |
| Current Consumption (Standby) | < 20uA |
| Current Consumption (Transmission) | < 15mA |
| Transmission Frequency | 433 MHz |
| Transmission Duration | < 1 second |
| Transmission Distance (to host) | > 80 m (line of sight) |
| Installation Gap (Emitter to Magnet) | < 1 cm |
| Encoding Type | Fixed Code |
| Dimensions (Emitter) | 75 (L) x 36 (W) x 16 (H) mm |
| Operating Temperature | -10°C to +40°C |
| Operating Humidity | < 90% RH |
| Shock Resistance | 4.7 M, 1.2 M, 3.5 M, 300 K |
8. Warranty and Support
Specific warranty information for the KERUI D0251 sensor is not provided in this manual. Please refer to the product packaging or the official KERUI website for detailed warranty terms and conditions.
For technical support, troubleshooting assistance beyond this manual, or inquiries regarding your KERUI alarm system, please contact KERUI customer service or visit their official support channels.