Specifications

ST900 Family General Handbook
667/HB/32900/000 Issue 11 Page 140 of 265
15.3.9 Solar Switch Override (SO)
An ‘SO’ control bit may be programmed to override the Signal Dimming facility (see
section 29.8) and switch the signals to the BRIGHT condition. Also see section 27.3
which details how the ‘SO’ control bit can be used by a local link.
15.3.10 Solar Override Confirm (SC)
An ‘SC’ reply bit may be returned to indicate that the signals are in the BRIGHT
condition due to any of the following sources:
a) the solar cell input (see section 29.8)
b) the dim override switch on the Manual Panel (if configured)
c) the ‘SO’ control bit being active
15.3.11 CLF Group Synchronisation (SG)
An ‘SG’ control bit may be programmed to reset the current CLF plan’s cycle time.
The synchronisation code is transmitted four times at 0101 levels, each level of 1-
second duration. The reset is actioned within 300 ms of the leading edge of the
second ‘1’ bit.
15.3.12 CLF Group Synchronisation Confirm (CS)
A ‘CS’ reply bit may be returned to confirm synchronisation of the current CLF plan’s
cycle time. The ‘CS’ bit is maintained for a pre-set period, configurable in 1 second
steps, normally set to 3 seconds.
Also see the reply bit ‘GR1’ (section 15.4.5).
15.3.13 Lamps On/Off Control Bit (LO)
If Part-time mode is configured it may be programmed to be introduced and the
signals switched off (or overridden and the signals brought on) by the presence of
an ‘LO’ control bit. The ‘LO’ bit should be programmed so that it has to be present
for at least 10 seconds before it is actioned and then absent for at least 10 seconds
before being cancelled.
Part-time may be configured as signals flashing for non UK controllers.
15.3.14 Lamps Off Reply Bit (LE)
An ‘LE’ reply bit may be returned to confirm that an ‘LO’ control bit to introduce Part-
time mode has been actioned. Alternatively, the ‘LE’ reply bit can indicate that the
signals have been extinguished for any reason, not just due to the ‘LO’ bit.
15.3.15 Signals Flashing Reply Bit (FR)
An ‘FR’ reply bit may be used instead of ‘LE’ to indicate signals flashing rather than
Lamps Extinguished.