3
Wiring other LED-based crossing signals (including Walthers)
If you are using another brand of LED-based crossing
signals, or are scratch-building your own, you MUST wire
them in a common anode (positive) manner.
NOTE: some
manufacturers use a black wire for the common wire but that
does NOT mean that it is a negative or ground wire!
Figure 2
at right shows you how to wire ONE single-sided signal; if
you are using multiple signals, or dual-sided signals, simply
duplicate the wiring shown for the additional LEDs. Each of
the
Grade Crossing Pro/2’s
signal outputs can handle loads
up 180mA (~12 LEDs). Note that EACH LED connection
requires a current limiting resistor. The value of the resistor
is dependent upon the voltage applied to the
Grade Crossing
Pro/2
. You can use Table 1 above to determine the minimum
resistor value. Note that some of the resistors can be ¼ watt
whereas others must be ½ watt. You can always substitute a
½ watt resistor for a ¼ watt resistor but you CANNOT
substitute a ¼ watt resistor for a ½ watt resistor!
common anode
Figure 2 – Wiring LED-based crossing signals
Wiring bulb-based crossing signals (e.g. NJ International)
Crossing signals constructed with bulbs do not have a
polarity like LED-based signals do. However, some bulb-
based signals may be pre-wired with a common wire. If your
signal does not, then you will simply create a common
connection from one lead of each bulb (it doesn’t matter
which lead is used). Figure 3 at right shows you how to wire
ONE single-sided bulb-based signal. The
Grade Crossing
Pro/2
will support two dual-sided signals; if you are using
multiple signals, or dual-sided signals, simply duplicate the
wiring shown for the additional bulbs. Note that current
limiting resistors are shown. These are only required IF the
voltage provided to the
Grade Crossing Pro/2
is greater than
the rating on the bulbs; most bulbs are rated at 12V AC or
DC but you should check the instructions that come with the
signal. If the
Grade Crossing Pro/2
voltage source exceeds
the bulb rating then add current limiting resistors as shown;
we recommend a value of 100Ω, ¼ watt.
Common
Figure 3 – Wiring bulb-based crossing signals
Flashing effects (True Lamp2 and Flash Rate)
As shown in the table on page 2 the
Grade Crossing Pro/2
has two configuration switches related to the crossing flasher
outputs (LO and RO). The first is TRUE LAMP2. When this switch (#2) is in the ON position the LO and RO outputs will
fade on and off which emulates older prototype crossing signals (when they used light bulbs). When this switch is OFF the
LO and RO outputs will simply turn on and off during the flashing activity; this setting emulates newer prototype crossing
signals which may use LEDs. If you are using bulb-type model railroad crossing signals we strongly suggest that you keep
this switch OFF.
The other flashing effect is the flash rate itself. The normal flash rate is selected when the FLASH RATE switch (#5) is in the
OFF position. If you prefer the faster (2X speed) rate you MUST have BOTH the FLASH RATE switch in the ON position
AND have the TRUE LAMP2 switch in the OFF position. As such you CANNOT have the faster flash rate and the signal
on/off fading effect at the same time.
End-of-Gate (EOG) LED
The
Grade Crossing Pro/2
has a separate output (EOG) which can be used to turn on an LED wired to the end (tip) of a
crossing gate. Like the prototype crossing gates, this output will be active (on) whenever the signals are flashing. It will be on
steady (the True Lamp2 configuration switch setting does not affect it). You will wire this LED just like the LO or RO LEDs
shown in Figures 1 and 2. Don’t forget the current limiting resistor! This output can handle loads up 180mA (~12 LEDs).
