The Entry Sensor tells the controller when a person (or object) passes in front of it. The sensor is compatible with both a shared Entry / Exit door and separate entrance only / exit only doors. The sensor has a range of six feet and can be calibrated to work in smaller spaces. The sensor can be set to tell in which direction a person passed it so it can automatically indicate entry or exit. Or the sensor can be set as a simple trip beam to either increase or decrease the occupancy count, regardless of the direction of passage. Essentially, the sensor functions like a flashlight beam, without – of course – emitting light.