Siemens ST950 - Logic Power Unit (LPU)

Mobility, Intelligent Traffic Systems
Sopers Lane, Poole, Dorset, BH17 7ER
Security classification
Unrestricted
Page
37 of 154
Version
7
Status
Issued
Last Editor
manpreet.jeerh
Date
January 2020
Document Name
ST950 ICM Handbook
Document No.
667/HE/45950/000
Copyright © Siemens plc 2020. All Rights Reserved. Mobility is a division of Siemens Plc
4.4 Logic Power Unit (LPU)
The Logic Power Unit (LPU) is a universal-input mains powered switch-mode
converter providing DC for the logic supplies of the CPU Card, I/O Cards and
Intelligent Detector Backplanes. The ST950ELV controller requires only the +24V
DC supply (Although the 5V supply is routed to the CPU Card as it is used on the
ST950LV controller). The +24V DC supply is routed via the CPU Card for
distribution to the I/O cards and Intelligent Detector Backplanes via the RJ45
cables.
Position
Function
Termination
Z32
Safety Earth Connection
d30
Mains Live Input
Z28
Mains Live Output (Not Used)
d26
Mains Neutral Input
Z24
Mains Neutral Output
(Not Used)
Z12,
b12,
d12
0V Return for CPU Card
X4
1,2,3
Z10
0V Return for CPU Card
X4
5
d10,
b10
+5V DC to CPU Card
X4
9, 10
b8
+24V DC (Not Used)
Z6
Power Fail to CPU Card
(Not Used)
X4
8
d6, b6
+5V DC to CPU Card
X4
11, 12
Z4
+24V DC to HPU
PL2
1
d4
+24V DC to CPU Card
X4
4
b2
0V Return (Not Used)