Specifications
ST900 Family General Handbook
667/HB/32900/000 Issue 11 Page 251 of 265
Note: If it is required that red lamp faults on the stand-alone pedestrian stream
extinguish all the signals of the controller, but some streams normally only inhibit
their pedestrian phases, then special conditioning can be used to switch off the
signals when the fault is confirmed. Do not select all the phases in the intersection
stream (as shown above in orange).
38.2.3.3 Other RLM Configuration Data
The following ‘switches’ affect the whole controller:
1st red lamp failures can be cleared automatically or require RFL=1,
2nd red lamp failures can be cleared automatically or require RFL=1,
2nd red lamp failures cancel the delays introduced by the 1st red lamp failures.
38.3 Stand-Alone Pedestrian Streams on an ST900
Two or more vehicle approaches on the same stand-alone pedestrian vehicle phase
can be red lamp monitored using one on-board sensor. However, this has the
disadvantage that if two red lamps fail on the phase, the controller would have to
extinguish the signals because it would not be able to determine whether the failed
lamps are actually on two different approaches.
If the two or more vehicle approaches are required to be separately red lamp
monitored, the following options are available to the configuring engineer:
38.3.1 Using External Sensors (ST900 Only / Not ST900 ELV)
The on-board / internal sensor can be disabled and two (or more) off-board /
external sensors can be used to monitor the vehicle phase.
For example, consider the case where a stand-alone pedestrian stream is required
in addition to a five-phase intersection where the intersection stream uses phases
‘A’ to ‘E’, and the stand-alone pedestrian stream uses phases ‘F’ and ‘G’.
If the two approaches of the stand-alone stream are required to be red lamp
monitored separately, the on-board sensor 6 can be disabled and two off-board
sensors 35 and 36 could both be configured to monitor phase ‘F’ for red lamp
monitoring and normal lamp monitoring. Note that sensors 33 and 34 can still be
used to monitor any regulatory signs on the intersection.