307UM0100_01 May 2016
PD17x User Manual
Page 23 of 31
8. Customer Fault Analysis
8.1 Fault Finding
FAULT
CAUSED BY
REMEDY
Red LED does not glow on power
up.
If the indicator is off 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 flashing 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
confirm fault. Check loop
installa�on and connec�ons.
Check on-board diagnos�cs to
confirm fault. Recut as per
installa�on instruc�ons.
Replace unit.
After tuning, the loop output LED
flashes
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
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 off to select the
frequency manually.
Switch AFS off
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.
