Ecolink Z-Wave PIR Motion Detector allows you to adjust the sensitivity of the sensor using the Jumper pins provided in the circuit board. The jumper can be found in the bottom-right corner of the circuit board once after you open the back case.
Go through the picture depicted below and place the jumper accordingly.
Full sensitivity - No jumper required
Small-size pet immunity - Put the jumper across PET1
Medium-size pet immunity - Put the jumper across PET2