Start-Up Mode; Part-Time Mode - Siemens ST950 Handbook

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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 mains supply to the controller is switched on or restored following a
mains 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.
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When a stream is in 'part-time' mode, all the signals in the stream are usually
extinguished allowing the traffic to flow normally. For example, it may be necessary to
control the traffic on a roundabout only during peak times, but not during the rest of the
day.
The normal method of switching between normal operation and part-time mode is by
means of the master time clock at specified times of the day.
An alternative method is by means of queue detectors. If a queue of traffic is detected,
normal traffic operations are introduced for a certain period, e.g. 20 minutes. At the end
of this period, Part-time mode is re-introduced unless a queue is still being detected, in
which case the normal traffic operations will continue until the queue is not detected for
a certain length of time.
Alternative signal sequences, e.g. flashing amber for traffic phases during the night
may be configured if required (for Non UK Controllers ONLY). For alternative signal
sequences, see section 31.
Part-time mode may be introduced by the following methods.
Time switch event and/or queue detectors (see above)
Handset (SWS handset command)
Manual Panel switches (SW1, 2 or 3 as configured)
Red Lamp Faults (to flashing part-time state for non UK only)
Correspondence Faults (for non UK only)
It is a requirement in the UK that part-time mode may only be used if accompanied by
the Red Lamp Monitoring facility.
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Copyright © Siemens plc 2015. All Rights Reserved.
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Paul Cox
ST950 General Handbook
Mobility Division, Traffic Solutions
Sopers Lane, Poole, Dorset, BH17 7ER
Page 79 of 107
Status Issued
Date 16-Jul-2015
Document No. 667/HB/46000/000
Mobility is a division of Siemens Plc