Specifications

ST900 Family General Handbook
667/HB/32900/000 Issue 12 Page 54 of 265
card has no impact on the above table. The sum total number of inputs and outputs cannot exceed
248.
3.13 LSLS
The LSLS card provides 32 current and voltage monitored switched outputs to the
ELV signal aspects. Each LSLS card is fitted into an LSLS backplane on the side
panels of the cabinet.
A maximum of 3 LSLS cards can be fitted into an ST900 ELV Controller cabinet.
Another 3 LSLS cards can be fitted into an adjacent cabinet, controlled by the same
ST900 ELV Controller.
With a 50Hz mains supply, the ST900 ELV Controller can support up to six LSLS
cards. With a 60Hz supply, the controller is limited to a maximum of four LSLS
cards. Also note that the controller is physically limited to three LSLS cards if the
‘cuckoo’ rack is used (section 3.4).
The LSLS backplane terminates the street cabling, allowing connection of up to 4
wires for each of the 32 aspect drive outputs and gives a total of 64 return
terminations
In addition, the LSLS backplane provides a connection for the power supplied via
the HPU; daisy-chained connections for the high-speed serial communications from
the PHS card or previous LSLS card; inputs for monitoring regulatory sign current
and a means of setting the address of the LSLS card.
Each of the 32 outputs has an associated ‘mimic’ LED showing the status of that
output. The LED is tri-colour and should be the appropriate colour assigned to the
output (except during Controller Self-Test).
From PB801 issue 8 onwards, the mimic LEDs can be extinguished automatically
while the cabinet door is closed to save power; see the ‘LED’ handset command.
Note
Hardware Fail Flash flashes all the signals on LSLS #1 and
extinguishes all the signals on the other LSLS cards, so at least two
LSLS cards are required. The IC4 Configurator automatically locates
the outputs that are required to flash on to the first LSLS card. Refer to
section 34 starting on page 234 for more information.