Specifications

ST900 Family General Handbook
667/HB/32900/000 Issue 12 Page 25 of 265
2.5 Mains Input
WARNING
When considering the connection of the controller to the incoming
mains supply, it is important to verify from the supplier that the mains
supply short-circuit current does NOT exceed 16,000 Amps.
If the mains supply short-circuit current can exceed 16,000 Amps, refer to Siemens
Poole for further information.
WARNING
The Master Controller Switch is a double-pole isolator and this must
be switched off before replacing the Master Controller Fuse.
2.5.1 Supply Transients
The ST900 has been designed to withstand transients as defined in
BS EN 50293:2001.
2.6 MDU
The MDU contains the dim/bright, A, B and SSR relays and the logic power supply,
providing +5V DC and +24V DC to the cards in the rack.
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
16A, 20A and 30A MDU variants are available. See the ST900 Installation
Commissioning and Maintenance Handbook for part numbers.
2.7 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 provides a high speed serial data link to the I/O cards and
Intelligent Detector Backplanes.