Specifications

ST900 Family General Handbook
667/HB/32900/000 Issue 11 Page 121 of 265
Care must be taken when using/testing independent inter-greens since the Extend
All Red facility terminates when the gaining stage comes to fruition (i.e. when all
fixed phases are at right of way) since the controller is no longer in an interstage.
Therefore problems may arise when the inter-greens to all fixed phases are
configured as independent and it is the inter-green to one or more non-fixed phases
which are to be delayed by the All Red Extensions.
All the fixed phases will gain right of way after their normal inter-greens have
expired and the gaining stage will come to fruition regardless of the extend all red
facility.
However, since the controller is no longer in an interstage, the extend all red facility
could be terminated prematurely, i.e. while All Red Extensions are still active.
If the Extend All Red facility is required to only delay the appearance of non-fixed
phases and not any fixed phases, a dummy fixed phase should be configured in the
stage which is delayed by the Extend All Red facility. This then prevents the stage
from coming to fruition until this dummy phase also reaches right of way.
10.2.3 Extend All Red (Hold I/G) Parallel Stage Streaming Facilities
There is an ‘extend all red’ facility available on each stream. There is a separate All
Red Extension time and All Red Maximum time for each stream.
The ‘extend all red’ facility monitors all of the phases in the stream gaining right of
way during the stage to stage movement. It waits until of these first phases reaches
the start of its red to green transition period. If the extend all red input is active, the
inter-green and phase delay times concerned with the inter-green are then held until
the All Red extension period terminates or the All Red Maximum time is reached.
10.2.4 Extend All Red Timings
One All Red Extension (REX) value is provided for all stage to stage transitions on a
stream. There is one value for each stream. The values are in the range 0.0 to 31.8
seconds in 0.2-second steps.
One All Red Maximum (RMX) value is provided for all stage to stage transitions on a
stream. There is one value for each stream. The values are in the range 0 to 255
seconds in 1-second steps.
The programmed value may be changed via the handset using the commands in
brackets.
If alternative extension or maximum red periods are required for different red periods
within the same stream, this can be achieved by the use of separate All-Red stages.
However care should be taken to ensure that any all-red extensions operate as
required during different modes, see section 10.1.