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IRDOT-1 |
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PURPOSE:
To indicate the presence of a train
at a given location.. |
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DESCRIPTION:
The IRDOT-1 is an
infrared detector of trains. When it detects a train it lights an LED and
gives an output for activating other controls. The LED may be mounted on a
control panel. It is simple to wire, requiring 2 wires for power and 2
wires for the LED.. |
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USES:
As
the IRDOT-1 can operate in tunnels and detect all types of rolling stock
it
is very suitable for train positioning and indicating track occupation in
hidden sidings and loops. It is usually best to position the IRDOT-1
at the end of the loop where the front of the train is to stop. Once
the "train detected" LED lights the train can be stopped.
The IRDOT-1 operates in both light and in the dark.
It is also used to activate automatic controls. For example when used with
the SA8 Station Stop it is located at the positions where the train is to
start slowing and where it is to stop.
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WIRING:
This is as detailed below
, but full instructions are supplied with the IRDOT-1. |
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CONTROL
PANEL: We supply the
IRDOT-1s with a 5mm
diameter red LED screwed to the correct terminals. The IRDOT-1 can
also operate a green "not occupied " or a
bicolour LED. |
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The
terminals of the IRDOT-1 are numbered. on the underside of the circuit
board. |
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1 To positive power
supply |
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2 Electronic switch (open collector transistor) |
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3 11 volts output |
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4 Not used |
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5 To long leg of LED |
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6 To negative power supply and short leg of LED |
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The
infrared emitter and detector are on the reverse side of the circuit board and
therefore not visible . |
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OCCUPIED/NOT OCCUPIED:
The Control Panel may be
arranged to show both "occupied" and " not occupied
states". This may be achieved by either separate red and a green LED,
or by using a bicolour LED. |
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Red
"occupied" plus green "not occupied" LEDs:
The
electronic switch of the IRDOT-1 will light an additional green "not
occupied" LED. A 1K resistor (shown by the brown rectangle) is used to limit
the current through the green LED. |
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Bicolour
LED:
A bicolour LED can
also be used. This will light green when no train is present and red when a
train is detected. |
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TRIGGER
FOR OTHER MODULES: The
IRDOT is used to activate other units when it detects a train.
Terminal 2 will trigger the Dual
Timer, IRDASCs, latching
relay board, alternate route selector and SA units. This is described later.
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OPERATING
RELAYS: The electronic
switch output of the IRDOT-1 will operate many types of relay. A relay of
any voltage can be switched subject to a maximum coil current of 100 ma.
If the relays coil voltage is 12 volts, it can use the same supply as the
IRDOT-1. When operating a relay this way the power supply must be smoothed
12 volt D.C. |
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Connection
to Digitrax DS54 stationary decoder: |
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The
Digitrax stationary decoder requires an input that changes from less than
6v DC to greater than 6v DC. This can be provided from terminal 5 of
the IRDOT-1. Use a separate power supply for the IRDOTs.
Connect the 0v DC of both the IRDOT and Digitrax power supply
together. Remove the LED from the terminal and link terminal 5 to
the Digitrax input. An LED train occupation indication can be
provided by linking from terminal 2 to the short leg of the LED, then
wiring a resistor from the long leg of the LED to terminal 3. |
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HOW
THE IRDOT WORKS: See Train Detection |
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SPECIFICATION |
| Voltage |
12
to 16 volts, AC or DC |
| Maximum
current consumption |
25
m A |
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SIZE |
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Inches |
Millimetres |
| Length x Width |
3 .45
x 1.2 |
88 x
30 |
| Height (
Board to highest component) |
0.7 |
17 |
| Height of
infrared components |
0.9 |
22 |
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