Post on 08-Nov-2014
Smartlock 400 – SSI Comparison
It is provided as a source of
information to assist those already
familiar with UK SSI architecture in
their understanding of the features
of Smartlock 400.
Single SSI with Signaller’sEntrance/Exit (NX) Panel& Local TracksideCommunications
The simplest SSI architecture is
illustrated in Figure 1. This shows
a typical small scheme, with the
signaller and SSI interlocking
co-located and the trackside
area of control in close proximity,
allowing the trackside equipment
to be controlled via dual trackside
data links using Data Link Modules
located inside the SSI cubicle.
The trackside data links may be
diversely routed to counter the threat
of simultaneous malfunction of both
links owing to a common cause.
This brochure lists the major similarities anddifferences between a Solid State interlocking (SSI)and Smartlock 400 (SML 400) system.
Smartlock 400 – SSI Comparison
4
CONTROL ROOM
EQUIPMENT ROOM
TFMNetwork
TRAIN DESCRIBER PMUX
NX PANEL
SSI
MPM 1
MPM 2
MPM 3
Diag M
PPMs
TECH TERM
DLMs
Figure 1 Single SSI with Signaller’s Entrance/Exit (NX) Panel & Local Trackside Communications.
5
CONTROL ROOM
EQUIPMENT ROOM
IMnet
I/OChannel
1
CC1 CC2
2003
CC3
I/OChannel
2
F/EN
F/ER
GWA
GWB
Support SystemMaintenance
Signalling TechnicianIncident Investigation
TRAIN DESCRIBER PMUX
NX PANEL
DLMs
TFMNetwork
Figure 2 Smartlock 400 with NX Panel & Local Trackside Communications.
Smartlock 400 – SSI Comparison
6
SML400 architecture for a scheme such as
that in Figure 1, is shown in Figure 2. A
Central Interlocking, employing Alstom’s 2
out of 3 (2oo3) platform with standard
operating system and interlocking software,
is configured with additional, UK specific, NX
Panel software. The standard interlocking
software performs the logic equivalent to that
performed in SSI Multi-Processor Modules
(MPMs). The NX Panel software provides
panel display functions equivalent to those in
a Panel Processor Module (PPM), including
Panel Multiplexer (PMUX) and Train Describer
(TD) interfaces.
A single central interlocking can replace six
SSIs fitted with PMUX and TD interfaces.
Further Smartlock central interlockings can
be added to the same scheme. These
communicate with each other over a new
interface that is faster than the SSI’s Internal
Data Link (IDL).
Identical trackside data links and TFMs are
employed, but instead of being driven by
trackside comms processors in the MPMs,
they are driven via a Trackside Functional
Module Gateway communications system
(TFMGW).
The interlocking evaluates a complete set of
trackside controls in one “evaluation cycle”,
which are then passed to the Gateway (G/W)
Front End. The front end returns its current
image of the TFM replies to the interlocking.
The front end executes continuous cyclic
control/polls of the TFMs, using the most
recently received information from the
interlocking and recording the TFM replies to
maintain an up–to-date image of trackside
states. The gateway front end manages the
timing of the TFM Data Link protocol. The
remote gateways (which for a simple scheme
like this are co-located) manage just one
TFM poll/reply at a time, being slave to the
Gateway front end, but master for the TFMs.
The “Support System” is provided instead of
the SSI technician’s terminal. This offers
improved functionality and is implemented
with modern supportable technology,
compliant to current standards.
Access to functions for:-
• System maintenance diagnostics
• Application and removal of signalling
controls such as route bars
• Logged data investigation.
Redundant hardware is provided to improve
availability and provide access points in
diverse locations for the different user types.
Smartlock 400 with NX Panel & Local Trackside Communications
7
Figure 3 shows a typical SSI arrangement
used where a VDU based signalling control
system (ICONIS, MCS, IECC…) is used to
control multiple SSIs whose trackside
equipment is sufficiently remote to require
access via Long Distance Terminals (LDTs).
LDTs may also be used where the trackside
equipment is close, but the diverse data link
is fed from the remote end to improve
availability. Access to the remote end is
often most economically achieved via a
telecom network.
The LDT is
designed to
operate via a
network offering
a G703 standard
interface.
Multiple SSI with Visual Display Unit (VDU)Signalling Control System & RemoteTrackside Communications
Smartlock 400 – SSI Comparison
8
CONTROL ROOM
EQUIPMENT ROOM
x2
WORKSTATION WORKSTATION WORKSTATION
PCMNetwork
DLM/TFMNetwork
DLM/TFMNetwork
ACTIVE CABINET 1
DLM
LDT
D&I G703Interfaces
SSI A
PPMs
MPM 1
MPM 2
MPM 3
ACTIVE CABINET 3
DLM
D&I G703Interfaces
DLM
ACTIVE CABINET 2
DLM
D&I G703Interfaces
DLMLDT
IDLB
IDLA
DLM
Diag M
SSI B
PPMs
MPM 1
MPM 2
MPM 3
DLMLDT
DLM
Diag M
D&I G703Interfaces
LDT LDT LDT
TECH TERM
Figure 3 Multiple SSI with Visual Display Unit (VDU) Signalling Control System & Remote.
9
CONTROL ROOM
EQUIPMENT ROOM
SERVER
Cnet
IMnet
N/WInterfaces
I/OChannel
1
CC1 CC2
2003
CC3
I/OChannel
2
F/EN
A1
F/ER
WORKSTATION WORKSTATION WORKSTATION
Support SystemMaintenance
Signalling TechnicianIncident Investigation
B1A2
B2
Standard Network(e.g. SDH, PDH...)
DLM/TFMNetwork
DLM/TFMNetwork
ACTIVE CABINET 1
GWA1
DLM
N/WInterfaces
ACTIVE CABINET 3
DLM
GWB2
N/WInterfaces
GWA2
DLM
ACTIVE CABINET 2
GWB1
DLM
N/WInterfaces
Figure 4 Smartlock 400 with VDU Signalling Control System & Remote Trackside Communications.
Smartlock 400 – SSI Comparison
10
The Smartlock 400 architecture for a larger
scheme is illustrated in Figure 4. Only one
interlocking is shown as a single Smartlock
400 CIXL is capable of managing the
equivalent of several SSIs, making links
equivalent to the SSI IDL only
necessary for the largest schemes.
The networks shown are duplicated
for availability.
The TFM gateway front end and
remote gateway components can be
distributed across a standard
telecomm network as shown.
Each TFM gateway front end can
manage 2 fully populated TDLs
(maximum 3 if only partially populated)
i.e. 4 remote gateways (maximum 6).
A Smartlock 400 interlocking can
control several TFM gateway front ends.
If the gateways are co-located with
the central interlocking, existing LDT
links may be used to communicate to
the trackside.
Smartlock 400 with VDU Signalling Control System & RemoteTrackside Communications
11
Smartlock 400 with Smart I/O
Architecture
A later release of Smartlock 400 offers a
replacement for DLM and TFM networks
and the TFM gateway, allowing the CIXL to
address a much greater number of I/O
points at increased speed. It will enable
migration of an existing trackside network to
this architecture by replacing the track data
link cable and DLMs, whilst retaining the
existing TFMs. New trackside networks will
benefit from a TFM equivalent with improved
remote diagnostics.
Functionality
Start Up
SSI has 3 modes of start up:-
Mode 1 (Cold) – Enforced when the system
detects extended power out or more than
one disagreement between the preserved
states of technician’s controls. This mode
requires confirmation from a technician to
start up – allowing the technician to re-apply
controls having consulted a paper log.
Mode 2 (Warm) – Enforced where mode 1 is
not enforced (not a lengthy power out and at
most one difference in the technician’s
controls), but significant differences in some
flag memory states. Flag states over which
there are differences are forced to the most
restrictive state, but the interlocking comes
on-line automatically after a time delay.
Mode 3 – Permitted where neither of the
other modes is enforced (few differences in
only certain flag memories permitted). The
interlocking continues without interruption,
forcing those flag memories where there
were disagreements to the restrictive state.
Smartlock 400 permits an equivalent to
modes 1 and 2. It protects from power
outage and permits hot swap board
replacement.
Normal Operating Mode
SML 400 Interlocking functionality will be
almost identical to conventional SSI, the only
behaviour variations when compared to SSI
being response times (within permitted limits).
Smartlock 400 – SSI Comparison
12
SSI introduces an average cross boundaryroute setting delay of 4 seconds, with amaximum of 8 seconds (excluding pointoperation times). These times increase to 8seconds and 16 seconds respectively if aroute crosses 2 interlocking boundaries.
Smartlock 400’s ability to manage larger areasavoids such delays and permits boundaries tobe chosen at less time-critical locations.
Key response times between an SSI andSML400 interlocking are similar. For SML400,the average time to revert a signal to dangerin the event of a change of trackside inputstate is less than 2 seconds. The maximumtime is less than 4 seconds.
A Smartlock 400 system can cover an areaequivalent to 6 panel SSIs, or 8 if controlledby a VDU based system. This number willincrease with the future introduction ofSmart I/O.
Maintenance IssuesDiagnosticSmartlock 400 diagnostic information ismade available to maintainers remote fromthe interlocking cubicle via standardcommunications networks.
On-line RepairSimilar to SSI, replacement of failed units inthe central interlocking cubicle can be effectedwithout taking the interlocking off-line.
Data RecordingIt is possible to perform a ‘live’ search backthrough 28 days of recorded history of thesystem’s behaviour and copy parts of thehistory onto media, for offline analysis, suchthat it cannot be altered and will survive 5years storage without degradation.
The SSI log is typically shorter than 28 days.
Performance
13
The main differences to an SSI scheme aresummarised below.
The initial stages of the process for configuringthe central interlocking data is the same asthose used for SSI. SSIsource files are initiallyprepared using thecurrent automated tool,then completed using atext editor tools to addcustomised data.
The desk check is soonto be assisted by a PCsimulation of the logicat this time, rather thanby visual inspectionalone – as is currentlythe case for SSI.
Pre-processing of the original SSI sourcefiles expands some of the “special”constructs into multiple standardconstructs. A compilation stage follows toproduce data that can be executed by theSmartlock 400 system.
Similar to SSI, a diverse de-compiler is usedto provide verification that the compiler hasnot introduced errors.
The physical media onto which the wholeinterlocking application is prepared for
insertion into the interlocking is a set of 3USB memory devices (rather than theEPROMs used for SSI). The contents of theUSB devices are diversified, forcingdifferences in software execution between
channels to improve safety. Unlike SSI, theUSB devices contain the fixed interlockingand operating system software, as well asthe scheme specific data.
Automated testing on a target platform isprovided to catch errors early and boostconfidence following changes.
Formal principles testing is undertaken on atarget system with external simulation,rather than the Design Work Station (DWS)as for SSI.
System Configuration
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As with SSI, a separate mechanism isprovided to check the interlocking identityand version number, to prevent incorrect orold data, or data for the wrong scheme frombeing used by mistake.
The TFM Gateway components must alsobe configured. There is no directly equivalentprocess for this with SSI, which employsconnector looping to set scheme specificaddresses on the LDTs.
Tool support is provided in the future forscheme design: Scheme Plans, ControlTables, CAD Design for build and tracksideinstallation, linked to the interlockingconfiguration data.
RAMS PerformanceThe main improvements in availability aredriven by improved, remote diagnosticfacilities to speed mean time to repair offailed components.
Smartlock 400 – SSI Comparison
Signalling Solutions Limited
Borehamwood Industrial Park
Rowley Lane Borehamwood
Hertfordshire
WD6 5PZ
Telephone: +44 (0) 20 8953 9922
Facsimile: +44 (0) 20 8905 1085
www.signallingsolutions.com
Prices are correct at the time of publication. Signalling Solutions Limited reserve the right to change specifications and prices.
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Issue 3 August 2010