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The Watchguard PIR detectors have a special firmware known as Dual Edge Sensing (DES). This enhances
the reliability of the detectors in all environments. DES is explained further below:
f) About Dual Edge Sensing (DES) Technology
Side view detection pattern in optimal temperature environment
This detector has Dual Edge Sensing (DES)
Technology, developed to eliminate false alarms
yet still provide maximum security.
The detector uses a pattern of infrared beam
zones to sense body movement. The detection
pattern in an optimal temperature environment is
shown opposite.
Each time you walk into or out of an infrared
beam zone this will be sensed and processed by
the DES technology built into the detector. The
red trigger light will not turn on until the detector
has made valid movement detection in normal
mode. This will only happen if the detector is not
in Intelligent Power Saving (IPS) mode.
Trigger examples in ‘least sensitive’ mode
When set to least sensitive, the PIR must receive 3 pulses before it will
trigger.
2 of the 3 pulse counts must be for different zones.
Both of the examples to the left will trigger the PIR, provided movements
1 to 4 are made within 10 seconds.
Trigger examples in ‘most sensitive mode
When set to most sensitive, the PIR must only receive 2 pulses before it
will trigger. Both pulse counts must be from different zones.
This example will trigger because two separate zones are crossed.
(3ft) (13ft) (30ft) (60ft)
