
301UM0031_01
TD136 Enhanced Vehicle Detector User Manual
Page: 11 of 29
3.2.4 Delay Time
Delay time is a mode in which the output of the detector is delayed by the time specified. If the vehicle
leaves the loop before the time has expired, no output will result. The mode is selected by switches
No.7 and 8 on the front of the enclosure and is as follows:
SW8
SW7
Off
Off
Off
On
Off
10 secs
Off
On
20 secs
On
On
30 secs
3.2.5 Reset Switch
The detector automatically tunes to the inductive loops connected to it when power is applied, whether
on initial installation or after any break in the power supply. Should it be necessary to retune the
detector, as may be required after the changing of any switch selections or after moving the detector
from one installation to another, momentary operation of the RESET switch will initiate to the
automatic tuning cycle.
3.3 Front Panel Indicator
While the detector is tuning, the ON (Red) LED will glow .The OUTPUT LED (Green) will extinguish
when the system is tuned. The green LED will flash at a rate of 1 Hz during tuning. This is used to
indicate the frequency of the loop to the user. Every flash of the LED is equivalent to 10 kHz. It will
stop when the operating frequency is reached. This operation is also performed whenever the reset
button is depressed.
The ON (Red) LED will glow permanently to indicate that the unit is functional. The red LED also
serves as an optical interface to the DU100 Diagnostic Unit.
If faults exist with the loop the green LED will come on and flash off at the rate of 2Hz indicating the
fault. If the fault is self-healing the detector will continue to operate but the LED will remain on
indicating to the user that a fault has occurred. The LED will go off for a moment during an undetect
indicating this, thereafter returning on. This condition can be restored by removing the power or by
depressing the reset button.
The green LED will also glow whenever a vehicle is detected passing over the inductive loop.