Transcript IEC/IEEE Train Communication Network

The IEC / UIC / IEEE Train Communication Network
for time-critical and safe on-board communication
Pierre Zuber, Bombardier Transportation, Pittsburgh, USA
Hubert Kirrmann, ABB Corporate Research, Baden, Switzerland
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What is the Train Communication Network ?
Wire Train Bus
Multifunction Vehicle Bus
Real-Time and Deterministic data transfer
Message Services
Available and Safe Architecture
Standardization of Vehicle data
ROSIN -TrainCom - ERRI projects
Conclusion
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The IEC Train Communication Network
Train Bus
Vehicle Bus
Vehicle Bus
Vehicle Bus
international IEC and IEEE standard for data communication aboard rail vehicles.
developped by IEC TC9 (Electric Traction Equipment) with the collaboration of:
railways operators:
manufacturers:
Chinese Railways
DB (Germany)
FS (Italy)
JRRI (Japan)
NS (Netherlands)
RATP (France)
SNCF (France)
PKN (Poland)
UIC (Union Internationale des Chemins de Fer)
UITP (Union Internationale des Transports Publics)
Alstom (FR, GB, BE)
Bombardier - ADtranz (CH, DE, SE)
ANSALDO (IT)
CAF (ES)
Firema, Ercole Marelli Trazione (IT)
Mitsubishi (JP)
Siemens (GB, DE)
Toshiba (JP)
Westinghouse Signals (GB)
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Objectives of the TCN
Define interfaces between programmable equipment's,
with the aim of achieving plug-compatibility:
1) between vehicles
2) between equipment aboard a vehicle:
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TCN’s network architecture
train bus
node
node
node
vehicle bus
vehicle bus
vehicle bus
vehicle bus
devices
The Train Communication Network consists of:
• a Train Bus which connects the vehicles (Interface 1) and of
• a Vehicle Bus which connects the equipments within a vehicle (Interface 2).
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Wire Train Bus (WTB)
standard communication interface between vehicles
node
node
node
main application
open trains with variable composition such as UIC trains
covered distance
860 m, 22 vehicles (including passive, retrofit vehicles)
number of nodes
32 (some vehicles may have more than one node)
data rate
1 Mbit/s over shielded, twisted wires
response time
25 ms cycle time
inauguration
assigns to each node its sequential address and orientation
references
thousand of vehicles in daily operation
conformance
ERRI (European Rail Research Institute, Utrecht, NL)
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WTB traffic
train attendant
diagnostic computer
locomotive
coaches for destination Y
coaches for destination X
driver's cab
driving coach
Vehicles of different types communicate over the train bus for the purpose of:
1) telecontrol
traction control: remote, multiple traction,...
vehicle control: lights, doors, heating, tilting, ...
2) diagnostics
equipment failures,
maintenance information
3) passenger comfort
next station, delays, connections.
seat reservation
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WTB wiring
Wiring over shielded twisted pairs, jumpers or automatic couplers between vehicles.
Fritting (voltage pulses) is used to overcome oxidation of contacts
Since there are normally two jumpers, wiring is by nature redundant
UIC specified a data cable ( 18 pole) compatible with the 13-pole UIC connector
WTB cable
Line B
Line B
classic
UIC lines
1
classic
UIC lines
1
jumper
Line A
top view
UIC data cable
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WTB node
2
WTB node
Line A
vehicle
jumper
WTB node
vehicle
redundant nodes
2
MVB - the standard vehicle bus
Why standardize the vehicle bus ?
MVB is important for:
• small equipment manufacturers
(reduced bus diversity)
• vehicle assemblers
(wider choice of suppliers, commissioning)
• railways operators
(less maintenance and spare parts)
All MVB devices are interoperable: there exist no incompatible options
MVB paves the way to interchangeability of equipment and simplified maintenance.
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Multifunction Vehicle Bus (MVB)
“standard interface for plug-compatibility between equipment on-board vehicles”
radio
power line
cockpit
Train Bus
diagnostics
Multifunction Vehicle Bus
brakes
power electronics
motor control track signals
data rate
1,5 Mbit/s
delay
shortest period 1 ms
media
number of stations
shielded twisted pairs and optical fibers
up to 255 programmable stations
up to 4095 simple sensors/actuators
status
tens of thousand of vehicles in service
time distribution
clock synchronization within a few microsecond
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Example: Vehicle Control Units
MVB
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MVB wiring
The MVB can span several vehicles:
Train Bus
node
repeater
MVB
devices
devices with short distance bus
The number of devices under this configuration amounts to 4095.
The MVB can serve as a train bus in trains with fixed configuration, up to a
distance of 200 m (EMD medium) or 2000 m (OGF medium).
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TCN combinations
Open train
860 m (without repeater)
MVB
0 node
(conduction vehicle)
0 vehicle bus
1 vehicle bus
(standard MVB)
MVB
WTB
(standard)
2 vehicle busses
(standard & not)
Connected train sets
WTB
(standard)
MVB
1 vehicle bus
not standard vehicle bus
200 m (without repeater)
Closed train
MVB
MVB
1 vehicle bus
0 vehicle bus
200 m without repeater
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MVB or other
(not standard)
TCN protocols
both the train and the vehicle bus use the same protocols
- reliable, demand-driven messages in
• point-to-point and
• multicast
Variables
Messages
Application
Interface
Application
Interface
common
Presentation
Session
Transport
Network
Multifunction
Vehicle Bus
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Wire Train
Bus
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other
bus
Network
Management
- deterministic (periodic) transmission
of time-critical process variables
Train and Vehicle Bus Operation
State Variable
State of the Plant
Response in 1..200 ms
Messages
Events of the Plant
Response at human speed: > 0.5 s
... commands, position, speed
• Diagnostics, event recorder
• Initialization, calibration
Periodic Transmission
On-Demand Transmission
Spurious data losses will be
compensated at the next cycle
Periodic Data
Sporadic Data
Flow control & error recovery
protocol for catching all events
Basic Period
Basic Period
event
Sporadic data
determinism is the condition for safe and available operation
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time
WTB and MVB: Integrity and availability principles
Both WTB and MVB comply with IEC 60870-5-1 integrity (HD = 4 on TWP, 8 on fiber)
A study at Carnegie Mellon University fully confirmed TCN’s integrity.
The TCN architecture allows to build a network without a single point of failure.
Duplicated physical layer is the default, single line is also possible.
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Further standardization
TCN laid the ground for standardization of data interchange not only between
vehicles but also between vehicle and ground (signaling) and radio links
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UIC (International Railways Union) train data
Electrical and data link interoperability is necessary, but not sufficient for interoperability
Once vehicles are able to communicate, they exchange their identification and capabilities:
e.g.
“I am a traction vehicle, my weight is 50 T, my length 23 m,….
“I support diagnostic data, passenger information, multiple traction,…”
The “mapping server” in each executes the protocol for cross-identification of the vehicles
To ensure “plug-and-roll”, UIC defined all traffic on the WTB:
UIC556
vehicle data
UIC557
diagnostic data
UIC647
traction data
UIC176
passenger info
operatorspecific
UIC556 cross-identification, process and message data formats
IEC 61375 / IEEE 1473 train and vehicle bus, process and message protocols
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ETCS - Eurocab
MVB is used as the vital on-board bus for Eurocab (European Train Control System).
To this purpose, safety protocols on top of TCN have been developed
Radio
Data
Logger
Clock
Vital
Computer
MVB
Track
Interface(s)
Balise
Interface
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Speed and
Distance
Measurement
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Brake
Traction
Interface
ManMachine
Interface
Safe Architecture
Vital and non-vital devices of different origin can interoperate over the same MVB.
Single channel, dual redundant and triple redundant devices can interoperate.
Safety protocols were developed for 2/3, 1/2 or coded processors,
provide time-stamping, authentication and value check over cyclic services.
intelligent
devices
(application
programs)
coded
monoprocessor
A
F c
and/or
diverse
programming
A
F1 F2
B
F c
triple modular
redundancy
and/or
B
F1 F2
A
F
B
F
C
F
untrusted bus
dumb devices
(no application
programming)
and/or
simplex sensor/actor
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and/or
duplicated sensor/actor
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triplicated sensor/actor
ROSIN - European Program
air conditioning
power
light
doors
brakes
Device: Door control
Made by: Westinghouse
Year: 1995
Revision: 1998 May 19
Parameters: position, status, indication, ...
...
Maintenance messages:
....
1996 Jun 25 10:43 23" low air pressure
1996 Jun 26 10:55 09" emergency open
1996 Jun 26 11:01 17" manual reclose
....
Universal
Maintenance
Tool
This multi-year (and multi-million $) project of European Union based on TCN.
It defined data interchange for passenger vehicles, freight trains, radio links,…
This work supported the parallel standardization in UIC 556 / 557
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RoMain - Rosin Maintenance
Remote web access over radio was demonstrated on the Eusko train
operators
manufacturers
remote
RoMain clients
Internet Explorer
Netscape
ADtranz
server
ERRI
servers
Ansaldo
server
Secure TCP/IP
Network
ROSIN server
radio proxy
RoGate
Bus A
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node
node
Bus A
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Bus B
IEEE standardisation
The IEEE Rail Transit Vehicle Interface Standard Committee influenced TCN
WG1 adopted TCN as IEEE 1473 Type T and defined interoperation with foreign components.
WG9 is working on information interchange standards and collaborates with UIC
WTB
WTB node
other bus
LVB
MVB
station
ML
gateway
MVB
station
MVB
Administrator
MVB
LSB
Operation of mixed systems in the USA showed the importance of strict definition of
interchanged data and how money spared by off-the-shelf is wasted in costly adaptations
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TRAIN
COM
TrainCom
The successful ROSIN project was followed by another European project: TrainCom.
TrainCom considers in particular:
- locomotive interoperability (multiple traction) in collaboration with UIC 647
- GSM radio links
MORANE
ERTMS kernel
TrainCom
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Acknowledgements
To all engineers of ABB, Adtranz, AEG, Alstom, Duagon, ERRI, Firema, I.PRO.M, Siemens,…
To the railways people in UIC which dedicated years of work in the standard groups
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Conclusion
• TCN imposed itself as the standard communication network in railways
• UIC did a great job in the definition of the application data, the industry could
readily support this effort in the ROSIN and TrainCom projects. IEEE RTVISC
WG9 has adopted UIC 556 as the basis for IEEE 1473-T train bus
data communication.
• TCN is a suite of communication and application protocols tailored for the
railways, not just a field bus.
• TCN is an open technology - there are no royalties, patents or copyrights.
Anyone can build a TCN according to specs - chips are available.
TCN source code is available on www.traincom.org
• TCN (MVB) has been adopted in electrical substations and printing machines
capitalizing on the work done by the railways community.
• Work on TCN is not finished - UIC, TrainCom and IEEE RTVISC WG9 are at work…
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Reserve slides
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Why not Ethernet instead of WTB ?
Ethernet uses a star topography (point-to-point to a hub). A train has a linear topography.
Ethernet would need special hubs which recognizes right and left in each vehicle.
Hubs would be a single point of failure, a battery failure in a vehicle would stop the bus.
Hubs cannot be used for freight vehicles (no battery in the vehicles).
In spite of providing 100 times more speed then WTB, Ethernet real-time response is not
better, because of overhead associated with transmitting numerous, small data items.
Ethernet is just a level 2 (up to data link) specification mutual identification of vehicles are yet
to be developed.
IP and UDP are too slow for time-critical data (traction data), reconfiguration in case of failure
takes several minutes.
there is no alternative to WTB as a train bus
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Process Data transmission by source-addressed
broadcast
Phase1: The bus master broadcasts the identifier of a variable to be transmitted:
bus
master
subscribed
device
subscribed
device
sink
source
subscribed devices
sink
sink
devices
(slaves)
bus
variable identifier
Phase 2:The device which sources that variable responds with a slave frame
containing the value, all devices subscribed as sink receive that frame.
subscribed
device
bus
master
sink
subscribed
device
source
subscribed devices
sink
sink
devices
(slaves)
bus
variable value
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The concept of real-time, distributed database
cyclic
algorithms
cyclic
poll
application
1
bus
master
Periodic
List
Traffic
Stores
cyclic
algorithms
application
2
Ports
Ports
cyclic
algorithms
application
3
source
port
Ports
sink
port
bus
controller
bus
controller
cyclic
algorithms
application
4
Ports
sink
port
bus
controller
bus
controller
bus
controller
bus
port address
port data
Bus traffic and application cycles are asynchronous to each other.
Bus and applications interface through a shared memory, the traffic store.
Cyclic bus traffic blends with IEC 61331-style of programming
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Hard Real-Time and Soft Real-Time
1 element
2 elements in series
e.g. vehicle bus and train bus
e.g. vehicle bus
probability
t1
probability
t1
t3
t2
hard
(cyclic)
t4
t2+t4
bounded !
response time
probability
t2
t1
t1+t3
still bounded !
t3
t2
t1
soft
(event-driven)
response time
t1+t3
unbounded !
Determinism is not a bus, but a system issue.
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unbounded !
Locomotive 465 Frame Occupancy
% periodic time
Already today, long frames dominate
number of devices: 37 ( including 2 bus administrators)
30 frames of 128 bits
65 frames of 64 bits
37 of 16 bits
18 of 32
49 frames of 256 bits
occupancy is proportional to surface
total = 92%
period
16 ms
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32 ms
31
64 ms
128 256
1024