ST950S Plus+ Installation and Commissioning Manual
Figure 14. 48V 480W Node PSU
In order to ensure high reliability, the Plus
+
system includes power supply redundancy, see below,
so that failure of one 48V PSU will not extinguish the signals, improving the availability of the Traffic
Signals. An additional advantage is that the 48V PSU can, individually, be swapped out without
impacting junction running.
3.6.1. Parts
48V PSU including Main Kit 667/1/53057/000
3.7. 24V PSU
The 24V PSU is a DIN rail mounted 100W device. The 24V PSU is used to provide the supply for the
ST950 CPU and the logic supply for the CIC(s). In addition, the 24VPSU is used to provide power to
auxiliary equipment such as I/O cards, including the IDB.
The 24V PSU has 1A spare capacity
and is rated such that it can provide sufficient power for the
following:
Table 9. 24V PSU Capacity for Aux Equipment
Number of I/O Cards
Number of SLD4
Number of WiMag Loop De
tector Replacement cards
1
24
0
1
12
2
3.7.1. Parts
Replacement 24V PSU 605/4/08717/000
3.8. Redundancy Module
3.8.1. Overview
The redundancy module is designed to be connected to two or three incoming 48V DC power supplies,
combining their power to produce a single 48V DC supply output for connection to a single CIC/CTB.
The module provides PSU redundancy by ensuring that if a PSU fails, the output is maintained by the
other supplies. The Redundancy Module combined with the 48V PSUs are collectively known as the
Power Bank.
The module provides load balancing to ensure that each connected supply provides an equal share of
power to the system, which maximises reliability.
Spare capacity is calculated after considering 3 CIC, CPU, 1 I/O.
5. With IDB
6. With 1 Access Point.
Page 45
