Cabling; Version 4 Status Issued; Last Editor Paul Cox Date 16-Jul-2015 - Siemens ST950 Handbook

Special conditioning in the controller must discriminate between short-duration fault
conditions (such as the tactile unit being temporarily held stalled) and a permanent fault
that requires maintenance.
When running a tactile unit with fault output where the fault output is not to be cabled
back to the controller cabinet, the fault output of the controller is left open-circuit.
Tactile unit fault outputs must NOT be paralleled.
4.10.10 ELV Regulatory Sign Expansion Kit
The ELV Regulatory Sign Expansion Kit derives power from the controller mains supply
to power additional ELV regulatory signs.
This kit is required if the total number of regulatory signs to be driven from the
controller exceeds the HPU capacity of 8.
ELV Regulatory Signs must operate from 33 to 58VDC rectified supply, measured at
the ELV Regulatory Sign terminal block. For power budget calculations, ELV
Regulatory Sign Extension Kit loading is the same as for signs powered from the HPU
regulatory sign supply (7 Watts per sign).
ELV Regulatory Signs Expansion kit: 667/1/33070/000.
4.11

Cabling

When estimating cable core and controller equipment requirements for the ST950 ELV
Controller the maximum cable lengths defined in the following tables on pages 60 and
61 must be complied with. There are also two wiring design and installation guides
667/DS/20664/000 LV, and 667/DS/20664/048 ELV, and these should be used for
further detailed reference information.
In order to keep the voltage at the signals within their specification, the voltage drop in
the installation must be no more than 4% of the incoming supply. The tables should be
consulted to ensure that the voltage drop is lower than this maximum for the selected
core size, distance and loading. If the voltage drop would exceed 4%, the cores /
conductors must be paralleled up to reduce it as instructed by the tables.
In addition the following guidance should be observed:
1. Where multiple cores are required due to long cable runs it must be noted that this
may require additional LSLS Outputs (and possibly an additional LSLS Card) in
order to accommodate the additional terminations in the LSLS Backplanes.
2. If common ground return connections were used it is possible for the failure of a
ground return connection to cause unexpected signal displays, where one or more
signals within a given signal head are incorrectly illuminated simultaneously. This
lack of ground return connection is not detectable by the controller because the
signal voltage presented at the controller terminals does not exceed the required
Security classification
Version
Last Editor
Document Name
Copyright © Siemens plc 2015. All Rights Reserved.
Unrestricted
4
Paul Cox
ST950 General Handbook
Mobility Division, Traffic Solutions
Sopers Lane, Poole, Dorset, BH17 7ER
Page 56 of 107
Status Issued
Date 16-Jul-2015
Document No. 667/HB/46000/000
Mobility is a division of Siemens Plc