7
68 ohms
1/4 watt
Detector
Blue
wire
Black
wire
Emitter
Black
wire
White
wire
Figure 11 – IR component wiring
(W1 input shown; replicate for E2, W2 and E1 inputs respectively)
Using an external detector
Use this sensor mode if you’d prefer to use a different type of detector such as an NCE BD20 current sensing detector. Any
brand of detector should work provided that its output is an open collector, “active low” polarity, which means that when a
train is detected the output is pulled to ground. When no train is sensed the detector output is an open circuit or “floating.”
You will need 3 detection blocks or zones. Figure 12 shows how they would be partitioned.
Signal
EB
Signal
WB
W E
West approach block
East approach block
Center block
Figure 12 – External detector block/zone partitioning
Figure 13 shows how simple it is to connect the BD20 block detectors to the
Block Animator
/2.
West
approach
detector
GND
OUT
Center
block
detector
GND
OUT
East
approach
detector
GND
OUT
NCE BD20
GND
2
1
OUT
Figure 13 – External detector wiring (NCE BD20 shown)
