Nortech PD27 Series - 8 Customer Fault Analysis; Fault Finding; Func�Onal Test

307UM0200_01 May 2016 PD27x User Manual Page 22 of 30
8. Customer Fault Analysis
8.1 Fault Finding
FAULT CAUSED BY REMEDY
Red LED does not glow on power
up.
If the indicator is o then there is
a fault on the power connection
to the unit.
Check power feed to the unit.
Aer the inial tune period the
CH1 and / or CH2 Green Channel
LED remains ashing at 2Hz.
Unit cannot tune to the loop due
to faulty loop or feeder
connecon.
Loop may be too small or too
large.
Faulty detector unit.
Check on-board diagnoscs to
conrm fault. Check loop
installaon and connecons.
Check on-board diagnoscs to
conrm fault. Recut as per
installaon instrucons.
Replace unit.
After tuning, the loop output LED
ashes intermi�ently and the
relay chatters.
The loop is geng spurious
detects due to:
a) Crosstalk with adjacent
detector.
b) Faulty loop or feeder
connecon.
a) Change frequency
seng.
b) Check that the feeders
are correctly connected
and adequately twisted.
When a Vehicle crosses the loop
there is no detect.
a) Loop wire shorted
b) The sensitivity of the
loop may be set to low
(unlikely this is a high
sensivity device).
a) Check the loop
resistance it should be
less than 6 Ohm
b) Set the sensitivity higher
Changing Frequency DIP switches
does not iniate a retune
AFS DIP switch need to be
switched o to select the
frequency manually.
Switch AFS o
Detector remains in detect after
the vehicle has le the loop.
a) Faulty Loop
b) Poorly Crimped
terminals
c) Loose connecon
a) Perform a Megger test
on the loop
b) Check Loop connecon
to terminals
c) Check splices are
properly soldered and
sealed.
8.2 Functional test
To test a detector, connect it to an inducve loop with a total inductance in order of 300 microhenries. (This may be
achieved in the workshop by winding (x) turns of wire on a non-metallic former of diameter (y)).