IRDOT-3D

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IRDOT-3D
Both the IRDOT-3 and IRDOT-3D have a built in double pole relay and the facility to also operate both detect and undetect LED's or a bicolour LED. The IRDOT-3D has in addition the following selectable delays: 3, 6, 9, 12, 15, 18, 21, and 24 seconds. These are selectable by connection to the terminal block.
Main Uses:
  • The same as the IRDOT-2D where a bicolour LED display is required.
  • Longer delay can be used to isolate a crossing line to prevent collisions.
  • Longer delay can be used as a switch for level crossing lights.
  • Simple 2 Aspect signalling. The unit is placed ahead of the signal and timing is selected to be long enough to keep the signal at green until the train has passed.
OPERATION
When the IRDOT-3D detects a train it lights a red LED and operates a double pole relay. The IRDOT is supplied with a 5mm diameter red LED connected to the correct screw terminals. This provides an aid while installing the IRDOT to check for reflections off obstructions. After installation the LED is wired to the control panel . The double pole relay is effectively the same as two single pole double throw (changeover) switches.
The diagrams below show how the relay contacts correspond to terminals.
LED WIRING
The IRDOT3 is supplied with the red (detect) LED fitted long leg to l short leg to k. This LED will light when a train is detected. A second LED may be fitted long leg to k short leg to l. This will light when not detecting. If a number of IRDOT3s are used each with a single LED these can be wired with long leg to l short leg to "0V".The advantage to this is that "0V" is a common connection thus nearly halving the number of wires needed.
The  two diagrams below show how to wire to both 2 leg and 3 leg bi-colour LEDs.
DELAY TIMES
As supplied the unit has a 3 second delay, i.e. it detects a train immediately but remains detected for 3 seconds after the train has left.
By connecting wires from the g, h, and i terminals longer delays are obtained.
Delay           g        h        i                 - indicates no connection,  x indicates connection
3sec              -         -         -
6sec              -         -         x
9sec              -         x         -
12sec            -         x         x
15sec            x         -         -
18sec            x         -         x
21sec            x         x         -
24sec            x         x         x
An example of 18 second delay wiring:

SPECIFICATION

Voltage 12 to 16 volts, AC or DC

SIZE

  Inches Millimetres
Length x Width 4.8 x 1.2 123 x 31
Height of infrared components 0.9 22