Siemens EH.75M.11. Especificaciones descargar pdf (Pagina 79)

T400 Controller Facilities Manual

667/EB/20200/000 Page 9-19 Issue 9

9.4 PRIORITY AND EMERGENCY VEHICLE MODE

Priority and Emergency Vehicle modes provide a facility in which appropriate vehicles

have priority in gaining and holding ROW over other vehicles.

Selective Vehicle Detectors (SVD) or transponder interrogators which respond only to

the appropriate type of vehicle, i.e. buses (or Light rail vehicles if light rail transit

system) for Priority mode and ambulances or fire appliances for Emergency Vehicle

mode, are used to distinguish the vehicles.

The output from the SVD or interrogator is used to insert a VA demand for the

Priority Phase and also provides an input for the associated Priority Unit.

The VA demand ensures that the phase gains ROW if the Priority Unit is inhibited and

also starts maximum green timers, VA as well as priority.

The input into the Priority Unit is converted into a Priority Demand for a specified

Priority Phase.

The presence of a Priority Demand will cause Priority or Emergency Vehicle mode to

become operational, subject to mode priority considerations. ROW will then go

immediately to the Priority Phase, subject to any delay caused by minimum green or

intergreen periods timing off. Any VA extensions will be curtailed and any VA

demands will be skipped.

Further outputs from the SVD while the Priority Phase has ROW will be converted by

the Priority Unit into Priority Extensions. The Priority Extensions will hold the Priority

Phase at ROW.

During Priority mode only:

(a) Any phases that have their VA extensions curtailed or their VA demands

skipped may be compensated next time they have ROW.

(b) Following the actioning of a Priority Demand, that demand and/or other

Priority Demands may be inhibited for a specified period. The timer

relationships are indicated by the figure in Section 9.13 of this document.

9.4.1 Definitions

Detection equipment designed to respond only to the appropriate type of vehicle unit

to D.Tp. Specification MCE 0117 or SPCL Specification 667/YA/17360 for buses and

MCE 0123 for emergency vehicles.

9.4.1(a) Priority Phase

A phase which is equipped with emergency vehicle and/or bus priority facilities.

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Siemens EH.75M.11. Especificaciones Pagina 79