LOGIC RAIL GCP/2 Instructions Manual Download Page 2

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If the train had not reached the WN sensor within 35 seconds of clearing the WF sensor then the

Grade Crossing Pro/2

will

assume  the  train  has  reversed.  This  “timeout”  will  cause  the  “action”  to  shut  off  as  previously  described  above.  Similar
behavior exists for a westbound train with respect to sensors EF, EN and WN (shut off occurs after the last car clears the WN
sensor). The WF and EF sensors may be located as far away from the crossing as you would like. If you are installing gates
then putting these farther  out  will  give the  gates enough time to lower before the train reaches  the crossing. An HO scale
train running a scale 40 MPH would cover 12 inches in about 1.5 seconds. You will likely choose to have your gates lower in
approximately  4  seconds.  So,  that  would  suggest  that  you  should  locate  WF  and  EF  around  36  inches  from  the  crossing;
consider  more  distance  if  you’re  running  faster  trains  or  less  distance  if  you’re  running  slower  trains!  If  you  are  NOT
installing gates then you can choose to place WF and EF wherever convenient and whatever amount of advance notice you
want to give your scale motorists before the train reaches the crossing!

You should make all of the connections to the

Grade Crossing Pro/2

before applying power to it. You can mount the

Grade

Crossing Pro/2

anywhere it is convenient underneath your layout using the four mounting holes provided. The holes will

accept #4 screws; do not enlarge the holes as damage to the circuit board can result and your warranty will be voided!

The

Grade Crossing Pro/2

board has a set of 9 configuration switches on it. Each switch is briefly described below with

more details later in these instructions.

Switch Name

Meaning when OFF/OPEN

Meaning when ON/CLOSED

SETUP

GCP/2 is in normal operating mode

GCP/2 is in sensor setup mode

TRUE LAMP2

Signals don’t fade on/off (like modern signals)

Signals fade on and off (like older signals)

SEN TYPE

Sensors are photocells or external current

detectors

Sensors are infrared

SEN POL

See text in the Sensor Modes section

FLASH RATE

Normal flashing rate

Fast (2X) flashing rate (see page 3)

GATES USED

Crossing gates are NOT used

Crossing gates are used

GATE DELAY

Signals flash for ~3 seconds before gates lower

Signals flash for ~1.5 seconds before gates lower

BELL MODE

The bell rings continuously while the signals

are flashing

The bell rings only when the gates are moving up

or down (must also have GATES USED ON)

BELL SHUTOFF

The bell shuts off when the flashing stops

See text in the Bell section

Wiring Tomar’s LED-based crossing signals

Tomar’s LED-based crossing signals are pre-wired in a common anode (positive) manner. Since these are dual-sided signals
(i.e. LEDs on both sides of each signal mast) there are 2 yellow and 2 red wires (one from each LED’s cathode) and one
common white wire. Figure 1 below shows you how to wire ONE signal. The

Grade Crossing Pro/2

will support two dual-

sided signals; if you are using two signals then simply replicate the wiring shown for the second signal. Note that EACH
LED connection requires a current limiting resistor. The value of the resistor is dependent upon the voltage applied to the
GCP. You can use Table 1 to determine the MINIMUM resistor value. You can always substitute a ½ watt resistor for a ¼
watt resistor. You can always use a higher value resistor (i.e. more OHMS!) if your signals are too bright to your liking.

)

Left Front (yellow)

Left Rear (yellow)

Right Front (red)

Right Rear (red)

Figure 1 – Wiring Tomar’s LED-based signals

Voltage supplied to

GCP/2

Minimum Resistor

Value

9V DC

390 ohm, 1/4W