User's Manual

SBS-900 Shore Based Radar Systems
Chapter 10: Corrective maintenance
KH-1602-2 issue 1: Standard SBS900 Systems Operator & Maintenance Handbook
Page 183 of 240
10.8.5 RDU overview
The Radar Distribution Unit provides the interface between the transceiver enclosure [h^ nb_ om_lm
command and display system, track extractor and optional service display.
The RDU comprises on the following main components:
Processor: A card frame mounted in the top half of the unit carries the modular interface
system backplane (MISB) and modular interface system modules (MISM).
The MISM modules used in the SBS-900 series are:
Radar
Processing
Module
Type 5
NTX-A462
SharpEye radar data and control and
LAN output
RDU processor backplane
Modular radar
I/O
type 9
NTX-A477 (3 off)
Analogue radar input/ output circuitry
for track extractor, service display
and spare output.
Modular
communications
module type 11
NTX
-
A478 Serial RS232 or
RS422
communications to service display
and track extractor.
CANBus communication to optional
Kelvin Hughes MANTADigital
processor.
Modular signal
I/O
type 4 Mk 2
NTX-A490
Safety and security switch inputs and
inverter control
Power supplies: DC power for the RDU is provided by a dual redundant auto ranging power
supply. The power unit has auto-ranging inputs so manual voltage setting is
not required.
Three-phase inverter: A three-phase inverter that provides power for the antenna sub-assembly
motor. The Inverter provides a 'soft-start' of nominally 2 seconds and a 'soft-
stop' (braking) of nominally 10 seconds. This reduces the high currents
associated with starting and stopping a motor under load.
AC breakers: The RDU contains a set of internally DIN rail mounted breakers for the single
and three-phase AC mains inputs.
The DIN rail also contains contactor relays which isolate the mains supplies
when the safety i-loop (Antenna Rotation or Man Aloft Switches) is broken.