Quad-Pic Servo Decoder Manual v1

Quad-Pic Servo Decoder Manual v1
Tam Valley Depot Quad Pic Servo Driver and Accessory Decoder Manual
The Quad-Pic Servo Decoder will control 4
turnouts with either DCC command control or
manually by pressing a button. It can also be used
for animation projects. It uses R/C airplane servos
which are ready available and inexpensive. The
decoder gets its power directly from the track bus.
The servos can either be powered from the same
bus or from a separate power supply. The QuadPic can also control other devices such as
semaphores, crossing gates and so forth by
connecting them to the servo arm.
DCC Address
Programming Jumper
Servo Endpoints and Speed
Programming Buttons and
7.5 - 18V
LEDs indicate
switch status
Connector for
Daughter Boards
Inputs from
Signal Systems
(see Appendix)
Separate 1.5A
Servo Power
4.8-6V DC only
Fascia Controller
Install the decoder by placing it near the turnouts you want to control and the fascia/control panel where
you want to mount the switches. Mount the decoder with a couple of wood screws through the mounting
holes, or use double sided tape. In some cases you may just want to leave the decoder floating and tack
down the wires around the decoder to keep it in place. Make sure to keep the decoder away from
conductive surfaces such as metal that could short the board. Also you can kill the board if let a hot DCC
wire touch the wrong part of the board. Make certain the board is free to ventilate the excess heat.
Connect the decoder to your DCC track bus just as you would connect a piece of track. Generally
speaking it is best to have your accessory decoders in their own power district and ideally with their own
Tam Valley Depot Quad Pic Servo Driver and Accessory Decoder Manual
booster. Tam Valley Depot makes a special accessory booster that will keep
the accessories powered at all time so that a locomotive short on the track will
not disturb your turnouts.
Servo Connection
Plug the servos in to the bank of servo connection pins as shown. Servos
have three wires, the power leads are black and red and the third, the signal
lead is white, brown, yellow or orange depending upon the brand. Plug the
servos in so that the signal lead is inboard and the black wire is towards the
edge of the board. If you do it incorrectly, it wonʼt hurt anything, but the servo
wonʼt move.
Button and LED Indicators - Fascia Controllers
The controllers supplied with the board can be used for manual operation of the servos. The controllers
use the same wires as servos to make things simpler. Connect these so that the white/signal wire is
inboard as for the servos (see pictures) for the main board. On the controller the white wire is on the side
away from the LEDs. The controllers can be rotated about the central screw for left-hand or right-hand
turnout operation.
To change the position of a servo press the button briefly. The corresponding LED will change on both
the controller and on the main board. Note that when you hold down button it causes one of the LEDs to
turn on while the button is held down - this is normal and does not indicate a problem.
DCC Operation
The decoder comes from the factory programmed for addresses 1-4. To move a servo, issue a DCC
accessory command by entering the address into the DCC system and then issue either a “t” or “c”
command. On Digitrax systems the accessory commands are accessed with the “Switch” button.
Consult your manual if you are unsure how to issue accessory commands on your system. You can also
change the turnout position manually with a button. Simply press the button to toggle the turnout position.
If you have installed the LEDs, the LEDs will change to indicate the turnout position. Note that it takes a
second or two for the points to move after the command is issued so avoid pressing the button
repeatedly. It wonʼt hurt anything but the points may not move to the intended position - in any case the
LEDs indicate the position the final position.
Programming (Training) the Servo Positions
The system ships with the servo endpoints set close to the center
position. To program the final positions, use the 3 buttons marked
Select, Up and Down. Press and hold Select for about 1 second
until the c LED starts flashing. You can then program the servo1
closed (c) position by pressing the Up/Down buttons. Press
Select briefly again to move the servo1 thrown (t) position and
use Up/Down to set the t position. The t LED will be lit. Press
Select again to change the servo speed with Up/Down. The t
and c LEDs flash alternately to indicate speed-set mode.
Press Select again to go to servo2 and repeat until all 4 servos are set. Each press of Select will move
to the next servo position (the controller LEDs will indicate the current position) until you have cycled
through all 4 servos and then it returns to the servo1 closed position.
Press and hold Select for approximately 1 second to exit the programming mode.
DCC Address
The decoder responds to accessory (stationary decoder) commands and ignores commands meant for
locomotives (i.e. mobile decoders). See your manual for your how to send an accessory command with
your DCC system if you are unsure. Your throttle may call accessories “switches”.
Tam Valley Depot Quad Pic Servo Driver and Accessory Decoder Manual
To program the DCC address, place the jumper across the two Addr pins and issue an accessory
command. The decoder will store the address and flash the LED twice to indicate it has been
successfully programmed. The decoder uses 4 consecutive addresses starting with 1-4, the next groups
are 5-8, 9-12, 13-16 and so forth. See the table in the appendix for a handy reference for those of us
who are algebraically challenged. You only need to enter the first number of each group to program all
four. At each address there are two positions “t” for thrown and “c” for closed (also called “normal” and
reverse” or “off” and “on” depending upon the throttle manufacturer). Be sure to remove the jumper when
finished programming. It can be stored on a single pin.
See the DCC Appendix for programming the decoder CVʼs.
The decoder interprets addresses in the range 513 through 1024 as routes. It will drive all 4 of the
servos to a set position when it receives a previously programmed route command. This is very handy for
setting up a group of turnouts to reach a particular yard or staging track. Several decoders can share the
same route commands so that a given route command can control as many turnouts as needed. The
decoder can remember up to 40 route commands.
To program a route set all the points in the desired position, put the Addr jumper into position as above,
and then issue an accessory command in the range desired. The LED will flash to indicate it has been
programmed. The number of flashes indicate the number of routes programmed. If the same address is
programmed a second time it will overwrite all earlier routes at that address.
Note: Many DCC systems have their own route programming built in to the controller. You are free to use
this system and ignore the route system built into the decoder - or you can use both systems if you wish
for different situations - itʼs your railroad.
The decoder has built-in memory so that it will remember its last state after the power is turned off.
Reset to Factory Defaults
To reset the memory to the factory defaults (Address 1-4, servos centered), hold down Up and Down
simultaneously while toggling the power. The t and c LEDs will flash 3 times to indicate a reset.
Installation of servos
There is a detailed article on mounting servos available online from the Model Railroad Hobbyist
Magazine http://model-railroad-hobbyist.com/download/mrh_issue3 and at the Tam Valley Depot website.
Servo Extensions
If the wire is too short to reach the decoder after installation, servo
extenders in various lengths are available form Tam Valley Depot or at
your local R/C hobby shop. Alternatively you can splice in extra lengths of
wire. The servos normally draw little current so that any wire 26 gauge
and above will work well. How many extensions can you add? In a test I
was able to add 15 feet of 26 gauge extensions and the servos still worked
well - at 20 feet the servos stopped working. A heavier gauge wire should
allow longer extensions, although I havenʼt made any tests.
The same extensions can be used for the controllers.
Y Extensions - Two servos or two controllers can be connected to the same port with a “Y” cable. Both
servos will operate simultaneously in the same direction and speed. If two controllers are on a Y then
both will show the same indication and, if either button is pushed, the turnout will switch. If the internal
power supply is being used (the default) no more than a total of 6 servos should be connected to a single
Tam Valley Depot Quad Pic Servo Driver and Accessory Decoder Manual
Using the Decoder on DC Railroads
The decoder can be used to switch turnouts on DC layouts using the button controller. You will need to
supply power to the decoder through the rail connector. The ACC terminals of a power pack can be used
or any power source from 7-24V AC or DC will work. Polarity is not important as the bridge rectifier on the
decoder board will correctly rectify the voltage. You will need to connect a momentary switch to control
the points.
Expansion Port
The 10-pin Expansion Port can be used to add a daughter
board to add more functionality to the decoder.
For example, the expansion board pictured to the right can be
used to add 4 relays to switch frog power. Notice that this board
also has an Expansion Connector allowing more boards to be
Keep an eye out at tamvalleydepot.com for more daughter
boards. I am always looking for good ideas - donʼt hesitate to
send suggestions to dmcree@tamvalleyrr.com
Signal Input Port
The 6-pin Expansion Port aalows for adding inputs from signal systems. A Signal Input board is available
that provides input terminals as well as jumpers to invert the sense of the signals. This board has optoisolators so there is no need to have a common power system between the servo subsystem and the
signal system.
External Servo Power (Option)
Jumpers configured
to use internal 1A
voltage regulator.
regulated 4.8-6V
Connection for external
4.8-6V power supply.
Red lead is (+).
The servos can be powered from the internal voltage
regulator or from an external power source. If you have
connected the board to your DCC system you may want
to use an external power supply for the servos to lessen
the load on your DCC system. (The other option is to
use a separate accessory DCC booster to power your
To use external power, connect the supplied connector
to your the board as shown and connect the other end
to your power supply. The supply should provide
More Help
If you need more help or have any suggestions/comments please email me at dmcree@tamvalleyrr.com.
Tam Valley Depot Quad Pic Servo Driver and Accessory Decoder Manual
DCC Address Groups
1, 2, 3, 4
5, 6, 7, 8
9, 10, 11, 12
13, 14, 15, 16
17, 18, 19, 20
21, 22, 23, 24
25, 26, 27, 28
29, 30, 31, 32
33, 34, 35, 36
Expansion Port Wiring
37, 38, 39, 40
41, 42, 43, 44
45, 46, 47, 48
49, 50, 51, 52
53, 54, 55, 56
57, 58, 59, 60
61, 62, 63, 64
65, 66, 67, 68
Fascia Controller Schematic
59, 70, 71, 72
73, 74, 75, 76
77, 78, 79, 80
and so forth to 512
Fascia Controller Drilling Guide (Actual Size)
Tam Valley Depot Quad Pic Servo Driver and Accessory Decoder Manual
Frog Relay Daughter Board
The Relay Daughter Board is to used to switch power to the turnout frog. It can also be used as a
general purpose relay under DCC control.
Plug the daughter board in to the 10-pin Expansion Port. It fits in only one orientation.
Plug the frog wires in to the 3-pin connectors. The frogs are numbered and correspond to the same
number servo. The green wire is connected to the frog and the other two wires connect to the track.
If the polarity is reversed simply reverse the 3-pin plug and correct the problem (right photo).
Stall-Motor Daughter Board
The Stall-Motor Daughter Board is used to drive 4 stall-motor switch machines (such as the Tortoise ™).
Plug the daughter board in to the 10-pin Expansion Port and connect the stall motors to the numbered
blue terminal blocks. You can now switch the stall-motor either by the fascia controller or DCC command
to the corresponding address. To change the speed of the motor use a small philips-head screwdriver on
the pot as in the photo on the lower right. If the motor drives in the wrong direction swap the drive wires
in the block to reverse the direction.
Tam Valley Depot Quad Pic Servo Driver and Accessory Decoder Manual
DCC Programming (Optional)
The decoder can be programmed in three ways to enable it to work with most DCC systems. (All the
functions can also be programmed with the three programming buttons, so DCC programming is not
required, nor is a DCC system needed to use the Quad-Pic for driving servos.)
The default address is 1 when the decoder ships or if a factory reset is done.
1) OPS mode for Accessory Decoders (programming on the main). If this mode is available then it is
the preferred mode. It can be done with the decoder in place. While there is no way to read back CVs
in this mode you can see the affects of the commands immediately. Not all DCC systems support this
mode however.
2) OPS mode as locomotive #1 (programming on the main). If the programming jumper is ON then
the decoder will respond to OPS mode commands address to loco address 1. It will do this even if its
accessory decoder address is not 1 but only if the programming jumper is ON. Make sure you do not
have a locomotive addressed as 1 on the track at the same time. Also put the jumper ON for only one
Quad at a time. Remove the jumper when done!
3) Direct Mode on a programming track. This is probably only useful for initial setup as it is
inconvenient to move the decoder to the programming track. For the decoder to have its CVs read
back at least one servo must be connected to generate the acknowledgment pulse used in reading
back CVs. Also a programming booster may be needed as is often the case for sound locomotives,
since the decoder draws a fair amount of power. We can recommend the PowerPax by DCC
Specialties. Even if the decoder does not respond properly to CV read commands it will record CV
writes properly. The t and c LEDs will flash briefly if the write is successful.
CV Table
1 - 127
The decoder responds to a group of 4 consecutive
addresses see table on previous page
Not used
High address
10 - 28
Not Used
30 - 33
Not Used
TVD has not been assigned an ID yet.
No uses of CV29 are currently supported
100 = Centered, 0 = minimum and 200 is maximum
throw for all the servo ranges
1 = slow creep and 40 = very fast
Tam Valley Depot Quad Pic Servo Driver and Accessory Decoder Manual
Controls the revering of DCC throw commands - i.e. if
set to 1 then a “c” is interpreted as “t” and vice versa.
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