SRC16 - Switch &
Route Controller Application Information
General
Information:
The SRC16 can be used in a number of applications. Track
plan panels, Centralized Traffic Control (CTC) panels,
fascia boards, motor drive, switch position reporting
(feedback) and DCC to serial bus (LocoNet®) gateway are
some types of uses for the SRC16.
The SRC16 can be power from the track voltage or a DC
power supply (9 to 12 volts).The power supply connector
is non polarized. When a DC power supply is used, either
terminal can be connected to plus or minus of the power
supply. When multiple SRC16s are used they can be all
connected to one power supply. The power supply must be
able to supply the current for all the SRC16s. The
plus and minus of the power supply must be connected to
the same power input terminal on each SRC16.
Be sure the power supply you use puts out the correct
filtered DC voltage when connected to the SRC16. Most
analog 'Power Packs' will not work because they do not
provide smooth (filtered) DC power. Also it must be
isolated from the system ground. That is, the power
supply can not have one of it's outputs connected to
ground (booster ground, loconet ground, house wiring
ground, etc). Some wall transformers have a ground
connection. Three prongs into the wall suggests the
negative output of the power supply is grounded.
The minimum LED current limiting resistor value is 470
ohms. This is a general guide line for a typical LED.
Resistor values of 1K work well with many LEDs. The
higher the resistance value, the lower the power supply
requirements.
In the examples below only switch group 1 is shown being
used. However, any group could be used and not all the
groups have to be configured the same.
LED connections:
Figure 1 below shows three different configurations in
which LEDs and the associated resistors could be
connected to a SRC16 group output. In normal operation
where only one of the group LEDs is turned on at a time,
all three configuration work OK. However, during lamp
check at power on and in "Smart Programming" mode when
both LEDs are turned on, both LEDs in configuration
Figure 1B may not be on and both LEDs in Figure 1C will
be off.
Note that the LED configuration in Figure 1A can also
represent a three legged bi-color LED (common cathode).
While the configuration in 1C can represent two legged
bi-color LEDs. Figure 1D can represent a three legged
bi-color LED (common anode).
Track Plan Panel:
Figure 2 below shows how push buttons and LEDs can be
connected to the SRC16 inputs and outputs. In this case,
when a button is pressed, the LEDs show the state of the
switch on a representation of the track plan. The push
buttons could be located near the LEDs or some distance
away on another panel.
The buttons could also be placed on a fascia board
without the use of the LEDs to provide local control of a
switch or a route.
CTC Panel:
Figure 3 below shows a CTC panel with a US&S
configuration. The switch lever can be moved freely at
any time. However, nothing happens until the button
(sometimes called "code start button") is pressed. Once
the button is pressed, the LEDs indicate the state of the
switch.
Switch Machine Drive:
Figure 4 below shows how a low current stall type switch
machine can be connected to the SRC16 outputs. The SRC16
has been tested with the Tortoise™ switch
machine and can drive up to eight of them. Programming is
the same whether using a switch machine or LEDs.
The SRC16 is NOT compatible with the SwitchMaster motor.
Each switch machine is connected to one of the SRC16
group outputs. One of the motor terminals is connected to
the closed (green LED) output and the other motor
terminal is connected to the thrown (red LED) output.
When the SRC16 receives a switch command for that group,
lets say a close command, 5 volts is applied to the
closed output. The thrown output is at ground, so 5 volts
is applied to the motor. It then moves in the close
direction. Likewise, when a throw command is received for
that group, 5 volts is applied to the thrown output. The
closed output is now at ground, so 5 volts is applied to
the motor in the opposite direction. Consequently, it
moves in the throw direction.
Since the SRC16 uses 5 volts for motor drive, the switch
machine moves slower than if 12 volts were applied.
The inputs can be used to control the switch machine or
can be configured as feedback as discussed next.
LEDs can be uesd as switch position indicators. The SRC16
does not have enough voltage output to drive
a Tortoise™ in series with an LED. However,
you can drive a Tortoise™ in parallel with a
LED resistor combination (in this case the resistor
should be at least 1000 ohms). You can also use the
internal contacts of the Tortoise with a LED resistor
combination powered by 5 volts from the SRC16 or by track
voltage.
Switch Machine Drive with MotoD:
To drive Tortoise™ with a higher voltage and thus
at a faster speed MotoDs can be used. To adjust the
speed of the Tortoise™ a series resistor
can be used. See the SRC16 manual. It is
recommend to connect all the
Tortoise™
and verify they are all working
before experimenting with a resistor value. Assuming
the SRC16 is powered from track voltage of 14 volts,
there will be a little over 12 volts applied the the
Tortoise™ . With 16 Tortoise™ connected, a
10 ohm resistor will drop the voltage about 2 to 3
volts (slightly slower). A 39 ohm resistor will
drop the voltage about 4 to 5 volts
(noticeable slower). The resistor power rating
should be 1 watt.
Switch Position Reporting:
The SRC16 can be used to report switch position which is
sometimes called switch position feedback. In some
situations it is desirable to know for sure that a switch
actually moved when it was commanded. Figure 4 below
shows the SRC16 inputs connected to
the Tortoise™ switch machine internal
contacts. Figure 5 below depicts micro
switches mechanically linked to the switch and connected
to the SRC16 inputs. When the switch moves internal
contacts close or a micro switch is activated, grounding
a SRC16 input. The SRC16 then sends a serial bus message.
Connector information:
Jameco : http://www.jameco.com
mating connector part # - 138377
10' flat ribbon cable, gray part # - 643794
10' flat ribbon cable, multicolor part # - 639672
connector installation tool part# - 73252
