LOGIC RAIL Block Animator/2-SBCA Instructions Manual page 7

Emitter
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.
West approach block
Figure 13 shows how simple it is to connect the BD20 block detectors to the Block Animator/2.
NCE BD20
White
wire
68 ohms
1/4 watt
Black
wire
Detector
Figure 11 – IR component wiring
(W1 input shown; replicate for E2, W2 and E1 inputs respectively)
Signal
EB
Figure 12 – External detector block/zone partitioning
GND
OUT
2
GND
1
approach
detector
Figure 13 – External detector wiring (NCE BD20 shown)
Blue
wire
Black
wire
Signal
WB
Center block
W E
OUT GND OUT
West Center
block
detector
East approach block
GND OUT
East
approach
detector
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