The train communication network (TCN) is a hierarchical combination of two fieldbus for data transmission within trains. It consists of the Multifunction Vehicle Bus (MVB) inside each vehicle and of the Wire Train Bus (WTB) to connect the different vehicles. The TCN components have been standardized in IEC IEC and UIC have now been issued as a set of international standards to overcome this situation: IEC , the Train Communication Network. STANDARD. IEC. First edition. Electric railway equipment –. Train bus –. Part 1: Train Communication Network. Matériel électrique ferroviaire .
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The train communication network TCN is a hierarchical combination of two fieldbus for data transmission within trains.
The wire train bus has been designed for international passenger trains with variable composition, consisting of up to 22 vehicles. The medium consists of a duplicated shielded twisted pair cable, which runs in the UIC cables between the vehicles.
Train communication network – Wikipedia
The connector between the vehicles is the pole UIC connector. Since connectors are exposed and can oxidize, a current pulse is applied at connection establishment to evaporate the oxide layer, called fritting. No repeaters are foreseen since vehicles in between can have discharged batteries.
A unique property of the WTB is the train inauguration Zugtaufe in which the newly connected vehicles receive an address in sequence and can identify the vehicle side called port and 61735 like in the marine so that doors open on the correct side.
Up to 32 addresses can be dynamically allocated. When two train compositions join, the addresses are reallocated to form a new composition of vehicles with a sequential address. Vehicles without WTB node “conduction vehicles” are not counted. The frames have a maximum payload of bits. The WTB operates cyclically to provide deterministic operation, with a period of 25 ms, used mainly for the traction control. The WTB also supports sporadic data transmission for diagnostics. The content of the periodic and sporadic frames is governed by the UIC standard.
The multifunction vehicle bus connects individual nodes within a vehicle or in a closed train set. The plugs and sockets are the same as used by Profibus with two 9-pin Sub-D sockets per electrical device.
There is no inauguration, the addresses are statically allocated. The physical level is using transmissions at a 1. The maximum distance is determined on the restriction of a maximum allowed reply delay of This explains why MVB and FIP have similar operation cyclic and event-drivenonly the arbitration method in case of multiple access differs, as MVB used a binary bisection mode relying of collision detection while FIP piggy-backed a “look-at-me” bit over periodic data. The MVB frames are not compatible with IEC fieldbus frames as it omits most of the preamble synchronization which is not required if zero-crossing detection is possible.
The difference came from the fieldbus physical layer which assumes a phase-locked loop to decode the Manchester data, requiring a preamble to synthonize the decoder, while MVB operated principally with optical fibres where this method is useless, MVB’s decoding relies on zero-crossing detectors and Manchester pattern recognition.
The MVB standard was introduced to replace the multitude of field buses in the train equipment. While the WorldFIP, CANopen, Lonworks and Profinet are controlled by international manufacturer associations targeting a wide range of application, MVB was tailored to the rolling stock application, with the goal of plug-compatibility, and therefore allows no options. This was intentional as the fight between the field busses raged in the s and the decision of the IEC that any of the eight field busses was a standard did not help plug-compatibility.
This is not due to the communication technology: But railways certification is costly and not always needed for uncritical applications such as comfort and passenger information. When total cost of ownership is considered, the cost of the hardware elements can easily be outweighed by additional engineering costs in the railways market with its small series.
MVB for critical operation such as traction control and signalling in the driver’s cab, and LON for uncritical and slow data transfer, but low-cost connections such as passenger displays and diagnostics. This separation is not iev observed. Additionally more and more components are added to rail vehicles that need far more bandwidth than any field bus can provide e. Still all the alternate vehicle buses are connected to the Wire Train Bus.
Train communication network
MVB is similar to FlexRayboth have the “process data”, which is called “static segment” in FlexRayand “message data”, which is the “dynamic segment” and are driven by a fixed TDMA scheme. Running FlexRay with 2.
Despite the similarities, no rail-manufacturer has considered FlexRay, since they valuated a common solution higher than a multitude of better busses. From Wikipedia, the free encyclopedia. Archived from the original powerpoint on Technical and de facto standards for wired computer buses. Interfaces are listed by their speed in the roughly ascending order, so the interface at the end of each section should be the fastest.