Specifications

ST900 Family General Handbook
667/HB/32900/000 Issue 11 Page 130 of 265
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The start-up mode is entered to produce a safe ‘signals on sequence’ when any of
the following conditions occur:
 The AC supply to the controller is switched on or restored following a failure.
 The signals are switched on by means of the SIGNALS ON/OFF switch or the
signals isolating switch (if fitted). This facility is optional. The alternative
option is that the signals turn on immediately at whatever point in the cycle
the controller has reached when the SIGNALS ON/OFF switch is switched
on.
 The signals are switched on (by the master time clock for example) after a
period of Part-time off / flashing.
 A second red lamp failure that has extinguished one or more streams is
manually cleared allowing the stream back on.
 Other failures that are configured to switch off the signals or to send streams
into their part-time flashing state are cleared.
13.1 Normal Start-Up Sequence
The standard start-up sequence normally consists of the three periods below,
although other start-up sequences can be configured, see section 28.2:
(a) Start-up Period
The start-up time is a period of 7 seconds which commences at the start of the
‘signals on’ request. During this period all signals for all phases are off.
(b) Amber Leaving / Red Display
Following the start-up blackout period:
 An amber-leaving signal is shown to all traffic phases not in the start-up stage.
 All traffic phases in the start-up stage continue to show blackout.
 All pedestrian phases show red.
(c) Starting Inter-green
At the end of the 3 seconds amber leaving, the traffic phases not in the start-up
stage change to red, the traffic phases in the start-up stage continue at signals off
and all pedestrian phases continue at red.
This state continues until the end of the starting inter-green, when the traffic phases
in the start-up stage change straight from signals off to green and any pedestrian
phase in the start-up stage change from red to green as normal. Any green arrow
phases in the start-up stage will also illuminate as normal.
The start-up mode is now finished and the controller will assume the highest priority
mode. During the start-up sequence demands are inserted for all phases to prevent
any vehicles being trapped against a red signal.