1 Underground Traffic Co-ordination

When the ‘cross/arrow traffic light’ LED enunciators (BLITE_IS) are used a highly visible (underground) solid red LED ‘cross’ is illuminated at each alarm site in the ‘red’ state. The cross is used as a ‘do not proceed beyond this point’ warning to vehicles. The alternate (green) state changes the red ‘cross’ display to a solid green ‘arrow’ at each alarm site. The arrow is used to indicate that traffic may proceed. A specially rated 220 Ohm resistor is switched across the 2-wire (either automatically or manually) for at least one second to change the output status. The controller can accommodate a maximum load of 4 BLITE_IS traffic lights and 4 BLLED_IS indicators and still be able to sense two simultaneous switch operations.