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.
After the initial 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
connection.
Loop may be too small or too
large.
Faulty detector unit.
Check on-board diagnostics to
confirm fault. Check loop
installation and connections.
Check on-board diagnostics to
confirm fault. Recut as per
installation instructions.
Replace unit.
After tuning, the loop output LED
flashes intermittently and the
relay chatters.
The loop is getting spurious
detects due to:
a)
Crosstalk with adjacent
detector.
b)
Faulty loop or feeder
connection.
a)
Change frequency
setting.
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 initiate 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 left the loop.
a)
Faulty Loop
b)
Poorly Crimped
terminals
c)
Loose connection
a)
Perform a Megger test
on the loop
b)
Check Loop connection
to terminals
c)
Check splices are
properly soldered and
sealed.
