Specifications

T400 Controller Facilities Manual
667/EB/20200/000 Page 25-17 Issue 9
25.4 ENHANCED RLM DETAILED DESCRIPTION
In descriptions below, references (C1), (C2) etc. refer to individual configuration items
described in section 25.4.5.
25.4.1 Operation On First Red Lamp Fail
25.4.1(a) Phase Appearance Delays
When the first red lamp fails (RLF1 indication) on a RLM group, the controller delays
the appearance of selected phases by configurable time periods.
The selection of which phases are delayed by a RLM group is made by means of
configuration data (C1).
The times by which the phase appearances are delayed, are configured for each phase
to phase change (C2 & C7). The actual delay applied to each phase (in addition to the
normal intergreen / variable all red) is the sum of:-
1) the RLM delay time for the phase,
plus 2) the longest time in the RLM phase-phase delay offset table which is
applicable to the phase to phase changes being made.
Phases can be configured with zero delay time in the RLM delay time array and in the
RLM phase-phase delay offset table, and thus will appear at their normal times.
RLM delay offsets can be applied to a phase, even though the phase appearance is not
controlled by any intergreen times i.e. where none of the phases losing right-of-way
conflict with a phase gaining right-of-way, the phase gaining right-of-way can still have
an RLM delay applied if this is specified in the RLM phase-phase delay table.
The RLM delay time (C7) for each phase can be altered via the handset. A range check
is applied to delay times entered via the handset and out of range values are rejected.
The high and low range limits are set in the T400 configuration PROM (C8).
The stage-stage moves on which RLM delays are to be applied can be selected by
means of configuration data (C12).
25.4.1(b) Effect On Intergreens, Holds And Demand Dependent Phases
The RLM delay time is computed and applied separately to each phase appearing
within the stage. For fixed phases within the stage, the RLM delay is applied at the
point when any relevant gaining delays, intergreens, SDE/SA extra clearance, and
holds (i.e. extend all red) have expired and the phase is about to gain right of way. At
this point, the phase is inhibited for the computed RLM delay time and then the phase
starts changing to right-of-way.