Nortech PD27 Series - Front Panel Indicators

307UM0200_01 May 2016 PD27x User Manual Page 10 of 30
3.3 Front Panel Indicators
The front panel indicators consist of a Red Power / Communicaon LED and one Green Channel LED.
There are four possible conditions which are indicated by the LED’s.
• Idle condion – no vehicle is detected
• Detect condion – a vehicle is detected passing over the inducve loop
• Tuning condion – the detector is currently tuning to the loop
• Fault condion – the detector is unable to tune to the loop as it is either out of operaonal condions such
as low signal strength or frequency out of range, or there exists a fault on the loop such as a short circuit
or an open circuit.
If a loop fault exists, the Green Channel LED will come on and ash at a rate of 2Hz indicang that the unit is trying to
tune. If the fault is self-healing, the detector will connue to operate but the LED will flash at a slower rate of 1Hz
indicang to the user that a fault has occurred. The detector must be power cycled or reset via the pushbuon in order
to clear the historical fault informaon.
In the event of a vehicle passing over the inducve loop and causing a detect, the Green Channel LED will light up
indicang the presence of a vehicle and remain on for the duraon of the detect.
It should be noted that the Channel LED does NOT necessarily represent the output state of the relays. It only represents
the detecon of a vehicle over the loop. The relay state could, for example, be different from the LED state in the case
of a pulse output aer its pulse duraon or a fault output. The only me the Channel LED will go off while a vehicle is
sll present is if the channel is in limited presence mode and has expired.
The Red Power LED indicates that the unit is powered and funconal. The red LED is also used as a communicaon
interface with the DU100 / DU700 to obtain diagnoscs.