User Manual

Operation Principles
3. OPERATION PRINCIPLES
3.1. Sensor placement
The sensor has a maximum detection range of 1640ft (500m). The recommended range for demanding
applications is 984ft (300m), to ensure detection of small objects such as humans, even in dicult weather
conditions.
There are two ways to create a continuous virtual fence with the sensors.
1. They can be placed 984ft (300m) apart and have an overlapping detection area as shown in figure A.
Sensor placement type A is recommended to get highest security level. With the overlapping detection areas, the
sensors cover each other.
2. They can be placed in pairs, with 1968.5ft (600m) between each pair, as shown in figure B. Sensor
placement type B allows for lower installation expense, with fewer points needing network connection. However,
it can create a weak point at the sensor’s locations.
NOTE: When placing the SiteWatch™ laser sensors opposite each other (as shown in B below), make sure
the lasers are crossed and not aimed directly at each other.
3.2. Laser divergence
The laser has a beam divergence of 2.0x0.2 m Rad. It spreads more in height than in width. This means that the laser
beam is approximately 1 x 0.1m at a distance of 1640ft (500m).
3.3. Multiple reflections
As the laser beam diverges, it is possible for the beam to hit multiple targets. Each target will cause a reflection back
to the sensor. The sensor’s algorithm analyzes the dierent reflections and calculates the distance to the
object. If it is more than 16.4ft (5m) between the objects, the sensor will only use measurements from the far object to
calculate the object position. If for example, a tree branch partly covers the sensor’s line of sight. The laser may still be
able to detect objects behind it. It is, however, strongly recommended to ensure that the
sensor’s line of sight is clear to maintain the highest performance.
7
SiteWatch™ sensor
SiteWatch™ sensor
SiteWatch™ sensor
SiteWatch™ sensor
SiteWatch™ sensor SiteWatch™ sensorSiteWatch™ sensor
1968.5ft (600m)
984ft (300m)
A
B
SiteWatch™ sensor
984ft (300m)
1640ft (500m)
3.28ft (1m)
SiteWatch™ sensor
SiteWatch™ sensor SiteWatch™ sensor
SiteWatch™ sensor SiteWatch™ sensor SiteWatch™ sensorSiteWatch™ sensor
SiteWatch™ sensor SiteWatch™ sensor
16.4ft (5m)
SiteWatch™ sensor
Calculated distance
984ft (300m)