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11.3 Panel Indicator Wiring
You can build a display panel with a track schematic and LEDs to indicate
track occupancy by connecting LEDs to the output connectors A, B, C, and D
shown in
Figure 6.
For a panel display of occupancy status made up with user
supplied LEDs, connect to the four 0.1" 2x5 headers, and wire up LEDs as
shown in
Figure 7: LED Panel Indicators Wiring
. DigiKey (1-800-DigiKey)
part number M1AXA-1036R-ND is a convenient plug and cable assembly that
you can use to wire LED indicators. Header “A” includes the 4 detection indi-
cators for detection sections 1 to 4 and the zone power indicator for zone A that
includes these four detection sections
The BDL168 incorporates current setting resistors to set the LED current typi-
cally about 3mA. If you use higher LED drive currents you can use external
transistors etc to amplify the LED current.
The LED drive from the BDL168 is active high at about +5 volts above the
BDL168 ground pin, via a 1 Kohm resistor. Note that the ribbon cable includes
separate ground return conductors for each LED that allow a 10 conductor rib-
bon cable to be split into 5 pairs to conveniently route to individual LEDS. Be
sure to connect the +ve active output leads to the LED anodes.
Figure 7:
LED Display Wiring
Resistors added to reduce sensitivity. See
Figure 2: Common Rail Wiring for full
view of schematic