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ST750
G
ENERAL
H
ANDBOOK
667/HB/33750/000
Page 36
Issue 6
Also note that if the Continuous Ped Demand (CPD) button on the manual is
pressed, then the red clearance of near-sided signals will be extended to its
maximum as required by TR2500A.
If an on-crossing detector has not been activated from the end of the preceding
pedestrian clearance period to the end of the current pedestrian steady green
period, then the clearance period is forced to run to its maximum.
A fault will not be recorded if this occurs, instead the controller will wait until the
normal DFM time-outs confirm and report a fault.
3.2 Pedestrian Modes Of Operation
A stand-alone pedestrian crossing can run any of the following modes of operation:
3.2.1 Fixed Vehicle Period
The vehicle phase appears at green for at least a fixed period. No vehicle detection
equipment is required.
If the pedestrian phase is demanded while this period is still running, the vehicle
phase remains at green. When the period expires, the vehicle phase loses right of
way and the pedestrian phase subsequently appears at green.
If the pedestrian phase is demanded after this fixed vehicle period has expired, then
the vehicle phase immediately (subject to the pedestrian demand delay see section
3.3.3) loses right of way and the pedestrian phase subsequently appears at green.
When the pedestrian phase has completed its green period and the controller has
executed the required ‘pedestrian to vehicle clearance period’ (see section 3.1), the
vehicle phase returns to green.
The fixed vehicle period is specified by the handset commands MEX, MFX, MGX
and MHX allowing four different times to be called up at different times of the week.
3.2.2 Vehicle Actuated
This mode requires vehicle detection equipment, either inductive loops cut into the
road’s surface or ‘above ground’ detectors (usually microwave detectors) mounted
on the signal poles. Activations on these inputs start (or restart) the ‘extension time’
for the phase and while this is active, the vehicle phase will (normally) remain at
green.
The vehicle phase appears at green for at least a minimum period specified by the
MIN handset command.