Renke RS-HWB-N01-3 PIR Motion Sensor - 24.00~24.25GHz Ceiling Mount, RS485 Modbus-RTU

This sensor uses dual-technology detection. The 24.00–24.25GHz microwave component detects motion based on Doppler shift, while the passive infrared (PIR) element senses body heat. Both signals must be confirmed to trigger an alarm, which significantly reduces false alarms caused by environmental factors like moving curtains or sunlight, providing higher reliability for security applications.

Connect the sensor's RS485 A and B terminals to your host controller's RS485 bus, ensuring proper polarity and termination. The sensor uses the standard Modbus-RTU protocol. You can read its status registers (e.g., alarm state, device temperature) using standard Modbus function codes (like 0x03) over the configured serial baud rate, which is typically set via software or DIP switches (consult the datasheet for default settings).

The alarm delay determines how long the sensor's output remains active after motion is detected. A shorter delay (5s) is ideal for immediate triggering in high-security zones. Longer delays (10s, 30s) are useful for occupancy-based lighting or HVAC control, where you want the 'occupied' state to persist briefly after a person leaves the area, preventing lights from flickering on and off.

No, the Renke RS-HWB-N01-3 is designed for indoor use. Its operating temperature range is -10°C to 50°C, and it is rated for up to 95% relative humidity but is not condensation-proof. It lacks a specific IP rating for water and dust ingress protection. For outdoor applications, a sensor with a proper IP65 or higher enclosure rating is required.