Walk test
When the mains supply is initially connected to the PIR occupancy switch it goes through its Walk test. This means it switches on for about 1 minute, then switches off and enters its automatic mode. If a manual wall switch is feeding the PIR occupancy switch then it will go through the Walk test each time the wall switch is switched on. By wiring the manual wall switch in the alternative position, the supply to the PIR occupancy switch is uninterrupted and it remains in automatic mode. It does not go through its Walk test each time the wall switch is switched on.