a single 9-12V
DC
source as shown in Figure 7 below.
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Figure 7 – DC power
Controlling an external bell ringer circuit
The “TO” (Trigger Output) terminal on the GCP can be used to trigger an external bell ringer circuit. The “TO” is active
when the gate motor outputs are on; it is an “open collector, active low” output which means that it is at ~0V when on and
looks like an open circuit when off. Figure 8 below illustrates how to control Innovative Train Technology’s GL Series bell
module (introduced in early 2017). A common DC power source is highly recommended; CONTACT US if you wish to use
an AC power source! Pay attention to the order of connections on the ITT module! As shown the bell module will play its
sound file as long as the TO output is active. If the crossing is active for a long time (more than a minute) you may hear a
brief gap in the sound when it reaches the end of its recorded loop and starts over again.
Note that if you have an older ITT module that does not match the photo below then please contact us for details on
connecting it to the GCP. You can also find those details in the Application Note “Interfacing to Innovative Train
Technology’s bell modules” under the Documents tab on http://www.logicrailtech.com.
DC Power
Source
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AC GND DC PWF PWN PEN PEF
+
GND
Jumper wire
Figure 8 – Bell ringer control
Multi-track grade crossings
There is an obvious tendency to just add additional sensors to handle additional tracks when you have a multi-track grade
crossing. The problem with this implementation is that the GCP cannot differentiate between two trains traveling in opposite
directions on different tracks. As such it could easily get “confused” and not provide the prototypical sequencing (i.e. the
action starts when the train covers a far sensor and the action stops when the train clears the near sensor on the other side of
the crossing). If you will have multiple trains traveling through the crossing area (with outer boundaries defined by the far
sensors) at the same time then you must use one GCP for each track. See the next section for details on how to cascade
multiple GCPs.
IF you operate your trains such that only ONE train can possibly go through the crossing area at a
time then you CAN simply add additional sensor sets (available from us) for the additional tracks.
In this
implementation you will wire the additional sensors the same way you did for their counterparts on the first track (i.e. per
Figure 6). So for example, the blue wire from ALL of the WN detectors will connect to the PWN terminal on the GCP.
