Siemens EH.75M.11. Especificaciones descargar pdf (Pagina 40)

T400 Controller Facilities Manual

667/EB/20200/000 Page 3-11 Issue 9

3.7.3 Appearance Type 2

The phase will only appear whenever its associated stage runs if demanded, although

there is no limit point for when the demand may be inserted. If the demand is inserted

before the stage runs then the phase will appear at the start of the stage. If the demand

is inserted during the stage then the phase will appear immediately. The appearance of

the phase in both cases will be subject to any relevant intergreen periods timing off.

When the phase appears its timing periods will be considered for the stage duration.

Therefore, if the phase appears during the stage its minimum green period, and

possibly maximum green period, may affect the termination of the stage. Therefore this

type should only be used if essential. Appearance Type 3 should be used unless the

phase is a filter green arrow.

The normal use for this type of condition is a filter green arrow phase as illustrated in

Figure 21.2 & Figure 21.3 with Phase D. The minimum green has been set to 0

seconds to prevent the green arrow appearance affecting the termination of the stage.

A demand for the filter green arrow should not be latched to ensure that a filter green

arrow demand does not exist without an associated main green demand.

The green arrow active should insert a demand for the main green phase.

3.7.4 Appearance Type 3

This is as Appearance Type 2 but the appearance of the phase after the stage has

commenced is inhibited after the expiry of a window period. The window period is

started by an opposing demand, except in UTC mode when it commences at the start

of the stage. Any demand inserted after this will be stored and can be configured using

a special software algorithm to affect the subsequent stage changes in different ways

(see section 3.7.2).

The window period is normally the difference between the longest maximum green

period of the other phases in the stage and the minimum green period of the

conditional phase. This means that the phase will not appear if there is not enough time

left for its minimum green to run and so will not affect the stage termination.

If the alternative maximum green facility is used, this may affect the required window

time. There are two ways to overcome this. One is to have a compromise window time

which will suit all of the alternative maximum green periods. The other is to switch the

window times along with the alternative maximum green times.

There are two methods to achieve switched window times:

(i) Alternate stages with the alternative window times are introduced and

deleted by the master time clock at the same time as the alternative

maximum green periods.

1 2 ... 35 36 37 38 39 40 41 42 43 44 45 ... 307 308

Sin comentarios

Siemens EH.75M.11. Especificaciones Pagina 40