Specifications

ST900 Family General Handbook
667/HB/32900/000 Issue 11 Page 168 of 265
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21.1 CLF Introduction
The ‘Cableless Linking Facility’ (CLF) allows a method of linking traffic intersections
along routes within an area using timing information derived from the ‘Master Time
Clock System’ (see section 25) in their controllers. Different Plans are used during
the day to cater for varying traffic patterns.
Each CLF Plan has its own configurable ‘cycle time’. At configured times (known as
‘group times’) within this cycle time, ‘group influences’ are programmed to affect the
operation of the controller.
Thus, at a particular time of day, a pre-defined plan can be introduced to enforce a
set of fixed duration effects on the controller.
Therefore, several controllers can each have ‘Plans’ designed for them. If they are
all introduced at pre-determined times and synchronised by an accurate Master
Time Clock System in each controller, it can be seen that the actions of the
controllers can be co-ordinated, so as to create a fixed time form of control for a
whole area.
21.2 Plan and Group Organisation
The configuration values described here can be viewed and modified using the
handset commands shown in brackets.
Operations in CLF mode are performed under control of up to 16 fixed time plans
(numbered 0 to 15) and each plan consists of up to 32 groups (numbered 0 to 31).
The range of the (CYC) cycle time is 1 to 254 seconds in 1-second steps. A value
255 indicates that the plan is not configured.
The range of the (PLT) group times is 0 to ‘the cycle time minus 1’, in 1-second
steps. Thus if the cycle time is configured as 60 seconds, the group times must be in
the range 0 to 59 seconds. A value of 255 indicates that the group is not used.
Each CLF plan is assigned to an influence set (PLI).
Each influence set contains up to 32 group influences (see section 21.3).
More than one CLF plan can be assigned to the same influence set if the functions
they are required to perform are identical and only the group times are different.
A CLF plan is introduced by a timetable setting with a function number of ‘1’. The
setting consists of the day code, hour, minute and second at which the change is to
be effected and the plan number to be brought into operation. A timetable setting
with function number of ‘0’ ‘isolates’ the controller, i.e. stops the current CLF plan so
the controller reverts to a lower priority mode, such as VA mode.