Peco Smart Switch Flyer

Peco Smart Switch Flyer
Using the Peco
How to install
servo motors to
operate turnouts
and semaphore
Originally published in
September 2014;
article and photography
by Craig Tiley.
he SmartSwitch™ servo control system is a recent addition to the Peco
range of electronic products, providing an alternative means of automated
operation for turnouts and semaphore signals. Servos are miniature dc electric
motors which are coupled to a gearbox
and an integral electronic circuit, to provide very low gearing and up to 180º of
very precise and powerful movement.
Advantages of SmartSwitch™
Traditionally, solenoid and slow-action
type turnout motors have been popular
with railway modellers – the electronic
circuitry associated with the programming of servos tending to put modellers
off. However, the Peco system is designed
as essentially a ‘plug and play’ installation
with comprehensive instructions to make
its use as straightforward as possible.
The main advantages of using a servo to operate
a turnout or semaphore signal are that it allows precise control over the pitch of the throw, is less noisy
(than the ‘zap’ of a solenoid) and the speed of the
throwing action can be adjusted to suit. The physical size of a servo assembly is also a lot smaller
than some of the popular types of slow-action
turnout motor, making it much more versatile and
suitable for confined spaces.
Servos can also be used to operate crossing gates
and other moving features on layouts, and are powerful enough for use with all scales and gauges up
to G. There is also the advantage that
SmartSwitch™ servos are powerful enough to
throw a Peco turnout without the need for modification, or removal of the over-centre spring.
SmartSwitch™ – what you get in the box
Peco offers SmartSwitch™ as a complete starter kit
in a box (ref.PLS–100) with sufficient servos and
components to operate four turnouts. Although,
upon opening the box, the electrical circuitry looks
rather complex, it is very easy to connect up; simply a matter of plugging the control board, servos
and remote servo programming boards together
with the leads supplied. The only external wiring
required – to be fitted by the user – is the connecting wires to the toggle switches (Peco PL–31 pushon terminal connectors and shrouds can be used),
and to connect a separate auxilliary 12V dc power
feed to the input connections on the control board;
on DCC installations the power feed can, if desired,
be taken from the track.
Preparing the servos for installation
Illustrated here is the arrangement for
pre-programming the servos on a
workbench, prior to installation on a
layout. The programming board is
linked to the control board, with
temporary power provided from a 12V
dc controller (via the black and red
wires on the right). The arrangement
for connecting a toggle switch has
been improvised; the masking tape
protecting against an electrical short
across the switch. The plug from the
servo is illustrated being attached to
port No.1 on the control board. The
programmed settings for each servo are stored on the control board, so each servo
installation needs to be assigned to one of the four ports, which it then retains for all future
programming and operation. Bench testing the servos like this also affords a good
opportunity to become familiar with the SmartSwitch™ system and the programming prior
to installation.
With power applied to the servo, the
first task is to set the servo
mechanism to its mid-position. This is
achieved by pressing the S3 button on
the programming board to scroll
through the functions until ‘L’ is
shown on the LED display. After three
seconds the servo will automatically
assume its mid position. This ensures
that when the servo horn is fitted,
there is an equal amount of throw
available in both directions;
particularly important if a 180º action
is required.
Illustrated here are the control board,
programming board (the smaller of the two), cable to
connect the programming board to the control board,
and comprehensive instructions. The starter kit also
comes with various fixings (not pictured) for
securing the control board to a layout baseboard.
With the servo set to its mid-position,
the required horn can now be attached.
Choosing which one of the three to fit
is very much dependent on the specific
installation of the servo – there’s no
hard and fast rules, and a bit of
experimentation may be required. The
horns are a push fit, and should be
fitted to the servo in mid-position also.
A screw (note that different sizes are
supplied) is then fitted to retain the
horn in place.
The kit comes with components for four servos;
the parts for one are illustrated here. Clockwise from
top left: servo mounting bracket, bolt for securing
servo to bracket, servo, toggle switch for operating
servo, wire linkage, screws to attach servo horns,
three servo horns and two wood screws to attach
mounting bracket to baseboard.
As supplied, the servo mechanism is
programmed to turn well over 90º; a
much greater throw than is required
for most installations. To avoid any
potential for damage upon linking up
(particularly to signals), the throw of
the horn needs to be reduced to less
than what is actually required – just a
millimetre or two in each direction.
The servo pictured here is being
programmed to achieve this; the ‘1’
denotes the number of the servo (1 of
4), whilst the ‘2’ refers to the
direction of the servo (1 or 2, which
are interchangeable). Buttons ‘S1’ and
‘S2’ are used to adjust the extremity
of the throw in each direction.
Operating a turnout with a surface-mounted servo
A 100mm length of
0.6mm steel wire is
supplied with each servo;
strong enough to provide
unsupported linkages across
short distances. Pliers and
snippers are used to fabricate
the linkage, joggled in the middle
to cater for the height difference
between the tiebar and the horn, and
with hooks at each end to retain the linkage
in place. The length of the linkage is judged by having the turnout
blades ‘chocked’ (with scraps of styrene) in mid-position.
With the servo
pre-programmed, it can be
fitted to the layout. I drew a line on
the baseboard to set the horn of
the servo in line with the turnout
tiebar. Peco turnouts have raised
spigots on the tiebar ends, which
can be sliced off to reveal a hole
through which the linkage wire can
be attached. Here marks are being
made through the mounting
bracket to drill pilot holes for the
two mounting screws.
With the servo and turnout mechanically linked, power can be applied, which will cause a sudden
initial movement from the servo. However, because of the pre-programming the amount of
movement will be restricted. (Note that linking up the servo and applying power with it set to factory
settings will cause the servo to overpower and damage the linkage wire.) Now the servo can be
adjusted so that – in each direction – the relevant turnout blade makes positive contact with the
corresponding stock rail. The programming board allows fractional adjustments to be made and also
enables the speed of the throw to be changed if desired.
The linkage wire is then attached as
illustrated with the tiebar end of the
wire routed up through from
underneath. Note the styrene ‘chocks’
referred to in the previous step. Upon
removal of the chocks, don’t be overly
concerned if the spring of the turnout
causes the blades to move across.
Operating a turnout with a servo mounted underneath the baseboard
Servos can be installed underneath a layout
to operate turnouts. In contrast to the
previous installation, the servo motor
illustrated here has been rotated through
180º within the mounting bracket, to give
greater distance between the horn and the
turnout tiebar. An overlength section of the
linking wire is cut and hooked onto the
horn as illustrated.
The horn is then fitted to the
servo by first threading the end of
the wire through the small hole in
the mounting bracket.
The servo is then programmed
to provide the required throw
in both directions. The protruding
end of the linkage wire can then
be trimmed back with snippers
to just above the the top surface
of the tiebar. Note that the arcing
movement of the horn causes the
linkage wire to pitch upwards
during the middle part of its throw;
this should be considered when
trimming the linkage wire to ensure it is
not cut too short.
To allow the wire to
pass up through the
tiebar, an 8mm
(maximum) hole needs to
be pre-drilled in the layout
baseboard directly in line
with the centre-point of
the tiebar. (This needs to
be planned in advance,
prior to final fixing of the
track to the baseboard.)
The servo is then installed,
with the mounting bracket
screws located either side
of the hole for the linkage.
The control board is supplied
complete with fixings to
allow it to be attached to the
underside of a baseboard, as
shown. The board should be
orientated such that the
socket into which the cable
for the programming board is
plugged remains easily
accessible. The arrangement
pictured here represents an
installation with two servos.
The toggle switches that are
provided with the servos are
intended to be mounted on a
control panel or mimic
Using a servo to operate a semaphore signal
A Ratio GWR home signal (ref.460) has been used here to demonstrate fitting a servo to
a semaphore signal. The plinth at the foot of the signal post has been fixed securely to
the baseboard surface. The servo has been attached so that the horn on the servo and
the signal operating lever (visible protruding below the black tubular housing) are in line.
The inset shows the mid-position that the semaphore arm needs to be set to prior to
fabricating and fitting the linking wire.
The servo needs to have been pre-programmed with
minimal movement prior to linking with the signal –
failure to do this will cause damage to the signal.
This view shows the shape of the linking wire used;
note the excess wire at the signal end to ensure
the linkage does not become detached.
Also available
The SmartSwitch™ kit offers
enough components to get started, and indeed may be sufficient
for smaller layouts with limited
turnouts and signalling. However,
because most installations will
require additional servos, these
can be obtained individually
(ref.PLS–125), whilst 1000mm
extension cables (ref.PLS–140)
cater for occasions where there
are longer distances between a
servo and the control board.
(ref.PLS–120) are also available
for situations where there is in
excess of four servos used.
Also available separately is a
‘Smart Frog’ (ref.PLS-130), an
optional circuit board that can be
used in combination with a servo
to change the polarity of the frog.
It needs wiring to the control
board, the track power and the
frog itself (it also needs its own
auxilliary 12V dc supply).
Regardless of the amount of
servos used on an installation,
only one programming board is
servos to be operated without the
toggle switches, if desired.
Endless possibilities
This article demonstrates the
installation of servos to operate a
two-way turnout (with the servo
mounted both above and below
the baseboard), together with a
semaphore signal. The focus is
centred around the mechanical
aspect of installing the servos and
fitting them to a layout; setting the
pitch and speed of throw using
the programming board is fully
described in the SmartSwitch™
instruction booklet, and so only
brief references to this have been
included here.
Although many modellers may
find adjustment of the servos to
be daunting at first, it is in fact
very easy to get to grips with. The
applications described here are
the simplest types of installation
for which the SmartSwitch™ system is suited; the potential uses
and animations being limited
only by the imagination and ingenuity of the individual.
Supplier information
DCC operation
SmartSwitch™ servos is possible
by connecting a Peco SmartSwitch™ stationary decoder
(ref.PLS–135) to the control
board. Each servo can be
assigned its own unique address
number, so that they can be individually controlled via a DCC
controller. This also enables the
Peco SmartSwitch™
products are available
from most Peco stockists.
More details can be found
where there is also a link
to a video which introduces
and demonstrates the
The movement of the servo horn then needs programming to suit,
much in a similar way as for the turnout installations. This pair of
views illustrate the two positions of the servo horn and signal arm
following programming. Any mistakes with the programming can be
corrected by performing a factory reset on the servo and starting
again. However, it is important to note that the mechanical linkage
between the servo and the signal (or turnout) should be
disconnected prior to resetting the servo, and then pre-programmed
prior to restoring the linkage.
Was this manual useful for you? yes no
Thank you for your participation!

* Your assessment is very important for improving the work of artificial intelligence, which forms the content of this project

Download PDF