Specifications

ST900 Family General Handbook
667/HB/32900/000 Issue 12 Page 51 of 265
3.8 LPU
The LPU (Logic Power Unit) is powered by the Mains 230V AC supply (or by the
Mains 110V AC supply, when the ELV transformer is wired for 110V or 120V input).
A switch-mode power supply mounted in the LPU produces +5V and +24V DC
supplies used by cards within the cabinet. These supplies are never taken outside
the cabinet.
The following supply voltages may be used:
Nominal Voltage
Minimum
Voltage
Maximum
Voltage Frequency Autonomy
200V to 230V 184V 264V
50/60Hz 4%
50ms under
max load
110V to 120V 92V 132V
3.9 CPU
The ST900 Family main processor card is paired with the PHS daughter card. The
two are bolted together and should not be separated.
The main processor card is the heart of the controller. It holds the controller
configuration and performs the function of configuration, control and management.
The primary external data interfaces of the main processor card are an Extended
System Bus interface to an SDE/SA Card and/or OTU Card, interface to the Manual
Panel and a front-panel serial interface to handset or Gemini
2
.
The PHS daughter card accepts parallel control data from the main processor card
and converts this into high speed serial data. One serial data connection is made to
the LSLS cards, one to the I/O cards and one to the Intelligent Detector Backplanes.
It is not important which of the two I/O connectors is used for the I/O Cards and
which is used for the Intelligent Detector Backplanes.
The PHS also acts as the ‘Second Processor’, providing independent safety
monitoring of the controller functions and therefore is also known as the Signal
Monitor.