©2004 Digitrax, Inc
www.digitrax.com
22
will plug into one of the 4 occupancy LED headers on the BDL168 and solder
LEDs to the wires to create an array of LEDs (see
Figure 6
). By plugging this
display array into one of the 4 occupancy LED headers (
Figure 5
, marked
A,B,C & D), you can see the state of the zone and occupancies for that header.
This allows you to easily check the zone sensitivity (typically 22 Kohms to
give detection). This also aids in the determination of detection number and
activity for a track detection section. Many detection problems are related to
wiring problems or poor connections to the detection section rather than to the
actual BDL168. By using the display array, you can eliminate the wiring issues
from the equation and be sure that the BDL168 is set up correctly.
Remember, if the zone power is OFF, the occupancy LEDs should be set up so
that they will be on to be sure that signaling systems or a CTC/dispatcher will
see the detection section in its most restricted aspect.
13.4 LocoNet Debug
If you are using LocoNet for reporting, be sure that the configuration is correct
for your usage. In normal operations the red “option” LED will blink ON
briefly when valid LocoNet messages are seen confirming a good LocoNet net-
work connection.
13.5 Analog Locomotives
The motor inductance of analog locomotives may in some installations cause
cross talk among the BDL168 detection sections. The addition of a 220ohm,
3 watt, wire wound resistor between the booster track terminals (Rail A and
Rail B on Digitrax boosters) will typically reduce the effect of this cross talk.
Simply use a leaded resistor as a jumper between the booster's two track termi-
nals.
13.6 Reducing Sensitivity for Outdoor Layouts
Outdoor layouts may require reducing sensitivity to allow for more accurate
occupancy reporting through the BDL168. Resistors are connected between the
detection zone and the zone common from the blue connector to reduce sensi-
tivity. A 1KOhm resistor will reduce the sensitivity by 1/2. A 100 Ohm resistor
will reduce sensitivity by a factor of 10.
13.7 Heat Sink Requirements
The BDL168 does not require a heatsink to operate efficiently, however you
can make your own to add to the unit. Please check the Digitrax website for an
application note on building your own heatsink for the BDL168