Azatrax SHS User manual

Installation Guide Azatrax Model Railroad Starter & Home Station Signal Control SHS
What it is: The SHS operates distant, home and starter signals on a single track at a station, generally following practice
derived from British railways.
Trains are detected by infrared sensors, independent of the room lighting. The rail does not need to be cut into isolated
blocks and resistor wheel sets on the train cars are not required.
LED signals must be used.
Signals with incandescent bulbs
need solid state relays such as
Azatrax model SSR6 between the
SHS and the signal.
The polarity of the
signals (common
anode vs. common
cathode is
automatically
detected by the
SHS.
Train direction:
For single direction rail traffic, place the "down" (approach sensor on the approach side of the station just past the home
signal. Place the "up" (departure sensor some distance beyond the departure end of the station. The starter signal will
change from green to red when the head of the train trips the up sensor. The home signal will change from red to green a
few seconds after the rear of the train clears the up sensor.
For bi-directional rail traffic, place the sensors about midway between a
home signal and the opposing starter signal.
Kit contents:
♦ Circuit board
♦ Infrared light-emitting diodes (IR LEDs with orange & white wire leads
♦ Infrared photo receivers with green & yellow wire leads
♦ Plastic mounting tubes. The tubes are for protection of the sensor leads and to provide mounting support. They are not
essential for detector operation and may be shortened or removed entirely to best fit your situation. Just use caution to
avoid damaging the leads.
Installation
This guide assumes an up/down direction of the track. If your track directions are east/west or north/south, make
appropriate substitutions -- and be consistent!
If using signals only for one-way traffic, install only signals for the "up" direction.
Install the sensors: Each sensor pair may be installed in one of two different ways - 'Across the Track' or 'Reflective.'
Across the Track sensing: The IR LED is positioned horizontally on one
side of the track, and the IR photo receiver is placed on the opposite side.
A train is detected when it blocks the light path between the LED and
photo receiver. The distance between the LED and photo receiver can be
up to 18 in. (46 cm , or more with careful alignment.
Tip #1 - If mounting the sensors vertically as shown here, slide the plastic tubes away from the sensor
then carefully bend the leads to a right angle. The leads are somewhat brittle, bending them more than
two or three times may cause a break.
Tip #2 - Locate the photo receiver so it faces away from bright lights or sunny windows. Use scenery or structures to
conceal the sensors and shade them from room lighting.
2019 Azatrax.com SHS starter - home signal installation guide pg. 1 of 4
down sensor up sensor
starter signalhome signaldistant signal
optional
station
Down
Up
"up" direction
down
sensor
starter signal, uphome signal, up
distant signal, up
optional
up
sensor
signal,
starter
down
signal,
home
distant signal,
optional
station
Down
Up
down down
To allow the starter signal to automatically
turn green, the end of the train must be
clear of the approach sensor when
stopped at the station. If not, manual
switch T1 or T2 will change the starter
signal to green (see pg 4).

Reflective sensing: Trains are detected when light from the IR LED is
reflected off a train and sensed by the IR photo receiver. Typically the
sensors are mounted in two 3/16-inch (4.8mm holes drilled in the
roadbed as shown here. Vertical installation works for S and larger
scales as long as there is no structure above the track such as a bridge.
Angling the IR LED and photo receiver toward each other is best for N and HO scale where the trains are close to the rail
head, and in places where an object above the track might otherwise cause false detections. Angle the IR LED and photo
receiver so their centerlines intersect at the height of the bottom of your rolling stock.
Tip #3 - You can ballast your track after sensors are installed. Cover each sensor with a bit of transparent tape. Apply
ballast. When the glue has dried use a dental pick or similar tool to remove ballast from the sensors. An opening of
just 1 or 2 mm is required.
Connecting wires to the terminal blocks: The SHS has 'spring cage' quick-connect terminal blocks.
♦ Strip 3/8 inch (1 cm of insulation off the end of the wire.
♦ Use a small screwdriver to push down (push, do not turn the terminal's button. Push firmly.
♦ While the button is pushed in, hold the wire at a 45 degree angle to the terminal block and push it in.
About 1 cm of wire should go into the terminal block.
♦ Release the button. Tug on the wire to make sure it is secure.
When two wires are connected to the same terminal twist the bare ends of the wires together.
Connect up sensor pair: Connect the orange wire from the IR LED to terminal EK. Connect the green wire from the IR
photo receiver to terminal EF. Now, how you connect the white and yellow wires to the SHS will determine whether the up
detector will operate in 'Across the Track' or 'Reflective' mode. See the diagrams below:
Connect down sensor pair: Connect the orange wire from the IR LED to terminal WK. Connect the green wire from
the IR photo receiver to terminal WF. As with the east sensor, how you connect the white and yellow wires will determine
whether the down detector will operate in 'Across the Track' or 'Reflective' mode. The two detectors may operate in the
same mode or in different modes.
When both sensor pairs are connected, there will be two yellow (or white wires in 'X' and two white (or yellow wires in 'R.'
Additional wire may be spliced to the sensor leads if needed. Use similar twisted pair wire for total length up to 26 ft (8m .
♦ Pairing is important! The IR LED that is connected to EK must be paired on the layout with the IR receiver that is
connected to EF. The IR LED that is connected to WK must be paired with the IR receiver that is connected to WF.
Connect power to the SHS: Connect an accessory power supply of 8 to 16 volts
AC or DC to terminals P1 & P2. The red and yellow ('E' and 'W' LEDs will briefly
flash to show that power is on and the circuit is working.
2019 Azatrax.com SHS starter - home signal installation guide pg. 2 of 4
EK
EF
X
R
WK
WF
green or blue
orange
white
yellow
east
sensor
pair
East sensor pair, Reflective mode
EK
EF
X
R
WK
WF
orange or red
yellow
white
green
West sensor pair, Across-the-Track mode
EK
EF
X
R
WK
WF
orange or red
yellow
white
green
West sensor pair, Reflective mode
west
sensor
pair
west
sensor
pair
or red
or blue
or blue
EK
EF
X
R
WK
WF
yellow
East sensor pair, Across-the-Track mode
EK
EF
X
R
WK
WF
orange or red
yellow
white
green
West sensor pair, Across-the-Track mode
EK
EF
X
R
WK
WF
orange or red
yellow
white
green
West sensor pair, Reflective mode
east
sensor
pair
white
west
sensor
pair
west
sensor
pair
orange
or red
green or blue
or blue
or blue
EK
EF
X
R
WK
WF
green or blue
orange
white
yellow
east
sensor
pair
East sensor pair, Reflective mode
EK
EF
X
R
WK
WF
yellow
East sensor pair, Across-the-Track mode
EK
EF
X
R
WK
WF
orange or red
yellow
white
green
West sensor pair, Reflective mode
east
sensor
pair
white
west
sensor
pair
or red
orange
or red
green or blue
or blue
EK
EF
X
R
WK
WF
green or blue
orange
white
yellow
east
sensor
pair
East sensor pair, Reflective mode
EK
EF
X
R
WK
WF
yellow
East sensor pair, Across-the-Track mode
EK
EF
X
R
WK
WF
orange or red
yellow
white
green
West sensor pair, Across-the-Track mode
east
sensor
pair
white
west
sensor
pair
or red
orange
or red
green or blue
or blue
P1
P2 power
supply

Test and adjust the sensors:
With no trains near either sensor pair, the 'E' and 'W' LEDs on the SHS module should be off. If either LED is on, correct
the false sensing condition.
To fix false sensing for Across-the-Track mode:
1. Verify that the sensor pair is wired correctly.
2. Make sure the IR LED and photo receiver are pointed at each other, and nothing is between them.
3. Shade the photo receiver from bright lights, and point it away from windows or other strong light sources.
4. Change the nearby room light from incandescent to a fluorescent or LED bulb if possible.
To fix false sensing for Reflective mode:
1. Verify that the sensor pair is wired correctly.
2. Pull the IR LED and photo receiver a bit deeper into the roadbed.
3. Infrared light may be 'leaking' through the roadbed material from the IR LED to the photo receiver. Push a metal shim,
such as the tip of a hobby knife blade, vertically into the roadbed between the IR LED and photo receiver.
4. Is there an object above the sensor, such as a bridge, or an upper layout level? Mount the IR LED and photo receiver at a
shallower angle, or paint the object flat black. Or use across-the-track sensing.
Are all detectors now off? Now test for train detection. Place a locomotive or car at the up sensor. The 'E' (red LED
should light. If the yellow LED also lights, re-adjust the down sensor pair for false detection (see above .
If the 'E' LED does not light, correct the up sensor pair for a false clear condition.
To fix a false clear indication for Across-the-track mode:
1. Verify that the sensor pair is wired correctly.
2. Adjust the sensor height so the train is fully blocking the light path from the IR LED to the photo receiver.
To fix a false clear indication for Reflective mode:
1. Verify that the sensor pair is wired correctly.
2. Adjust the sensors higher or lower in the roadbed.
3. A bright light source above and to the side of the track may be saturating the IR photo receiver. Try pulling it deeper into
the roadbed or create shade with scenery or a structure. Change the nearby light from incandescent to a fluorescent bulb.
Test with several types of rolling stock and adjust the sensors as needed.
Remove the train from the up detector, make sure the 'E' LED goes out.
Place a train at the down detector. The 'W' (yellow LED should light.
If the 'W' LED does not light, adjust the down sensor pair for a false clear condition (same process as above for the up
sensor pair .
Sensors must be working correctly before continuing the installation.
Signal Connections -- turn power off before changing signal connections.
With very fine signal wires, it is best to attach larger wires (AWG #26 or #24, or 0.2 mm2 such as found in telephone or LAN
cable , then insert the larger wire in the terminal block.
Resistors:
If signals are pre-assembled with resistors, first try the signals with their resistors. If the signal lights are too dim, remove
the resistors. The SHS has resistors on-board. This allows LED signals to be safely used without additional resistors.
♦ However ♦
When distant signals are connected,
and if the home and distant signals do not
already have resistors attached, then a
resistor needs to be added to the home
signal and to the distant signal as shown
here. This balances the brightness of the
red and yellow LEDs by allowing the
home signal's red LED and the distant
signal's yellow LED to share current more evenly. Use resistor values of 100 ohms or more. Diagrams above show two
possible ways to include resistors if the home and distant signals do not already have resistors attached.
2019 Azatrax.com SHS starter - home signal installation guide pg. 3 of 4
homedistant
resistor
resistor
SHS
Rtn
G
Y
homedistant
SHS
Rtn
G
Y
resistor
resistor

Operation:
When power is turned on, the SHS
does not know if the station track is
occupied or not, because a train may
have been added or removed from the
track while power was off. The home
and starter signals will show red.
Decide in which direction the train will
leave the station. If departing up,
momentarily close toggle switch T1.
If down, momentarily close T2. The
selected starter signal will change to
green.
If the home signals are red but a train is
not at the station, momentarily close
T4 to change the home signals to green
and permit a train to enter the station.
If T4 is not connected, a train may pass
the red home signal and enter the
station by permission of the
dispatcher.
Normally when the station track is
clear, the home signal is green and the
starter is red. As a train approaches
the station and trips the approach
sensor, the home signal changes to
red. The train stops at the station
with the starter signal ahead of the
train, viewable by the driver.
When the end of the train clears the
approach sensor, a timer starts on the
SHS module. If toggle switch T3 is
open, the starter signal turns green
when the timer runs out (normally 20
seconds . This gives the train
permission to depart the station. If T3
is closed ('on' then the starter signal
stays red until switch T1 or T2 is
momentarily closed.
To double the time that the starter signal stays red after the train arrives, place the configuration
jumper (connector block / shunt across both pins labeled "+R." ( +G and 4a jumpers do nothing .
When the locomotive reaches the departure sensor the starter signal turns red. A few seconds after
the rear of the train clears the departure sensor the home signal turns green. The starter signal
remains red, unless T1 or T2 is closed ('on' . Closing T1 or T2 clears the corresponding starter signal to green for the next
approaching train, permitting it to pass through the station without stopping.
For further information and assistance, visit the Azatrax website, www.azatrax.com
2019 Azatrax.com SHS starter - home signal installation guide pg. 4 of 4
switch name what it does when closed ('on')
T1 "up" clear
optional for 1-way
required for 2-way
Clears train for up departure by setting the up
starter signal to green. Momentary activation
allows the starter signal to return to red after the
train departs, stopping the next train. Leave it 'on'
to have a green starter signal for the next train.
T2 "down" clear
not used for 1-way
required for 2-way
Clears train for down departure by setting the down
starter signal to green. Momentary activation
allows the starter signal to return to red after the
train departs, stopping the next train. Leave it 'on'
to have a green starter signal for the next train.
T3 hold at station
optional
Prevents the on-board timer from clearing the
starter signals to green. Starters stay red until
cleared by switch T1 or T2.
T4 clear home signals
optional
If the station track is clear but the home signals are
red, thus preventing a train from entering the
station, momentarily close T4 to clear both home
signals to green.