Your Chuango PIR Motion Detector PIR-800/ PIR-910 might enter sleeping mode to save power.
When the PIR Motion Detector detects human body movements more than twice within 3 minutes, it will only send one alarm signal to the hub and then automatically enter sleeping mode. If no movement is detected within the next 3 minutes, it will exit the dormant state and return to the alert state.
* Note: If you want to confirm whether the PIR Motion Detector is working or not, you could arm the alarm system and leave for a while, make sure that no one is in the detection area for at least 3 minutes. If you enter the detection area of the motion detector again, the siren of the alarm system shall sound immediately.