The main distinctive feature of the sensors FM is the possibility to make secured passages on protected sites.
The example on the picture shows the sensor installed on a pole to the right.
You can see a secured passage on the level of the gate for transport (by deactivating Subzones 6 and 7).
So, the moving in Subzones 6 and 7 will not make the sensor trigger.
Totally the sensor has got 12 subzones which can be activated/deactivated.