“Strictly according to protocol”
Railway applications are becoming more and more complex. Melanie Kleinpötzl, Frauscher Product Management, explains in an interview how high-performance software protocols guarantee the essential problem-free communication between systems.
Software protocols open up a wide range of possibilities in the railway sector.
It is impossible these days to imagine the railway industry without digitalisation and networking. What role do software protocols play in all this?
The use of digital data has opened up a wide range of new and improved applications to the railway industry. This has facilitated the mutual exchange of a wide variety of information between systems. But this transfer of data needs more than just suitable interfaces. Digital communication only becomes possible by implementing the relevant protocols – thereby giving them a key role.
Selecting the optimum software protocol must therefore be taken into consideration at the project planning stage. Either a protocol that is already being used in the existing system is adapted, or a protocol that is alien to the system or a completely new protocol is fed in or developed. In any case, there are different factors that should or must influence this decision.
Many system integrators are already using specific protocols. What should they consider when making adaptations if new components are to be integrated?
We have already implemented three projects where this very approach was chosen. This has allowed us to gather valuable experience in the interplay and compatibility of protocols and interfaces and we know that having precise knowledge of the respective protocol specifications, for instance with regard to the initialisation process, is indispensable. Basic prerequisites must also be fulfilled at hardware level. The adaptation of existing protocols can therefore incur considerable costs, depending on the requirement.
But, if a system integrator has implemented a secure protocol of its own in order to bring about communication between interlockings or in order to communicate with the elements located in the field, then the connection of, for example, an axle counter or tracking solution via that very same protocol will be the simplest and most effective solution for the system integrator concerned. This is because this guarantees that additional data can be easily integrated into the existing system environment and then processed further.
And what are the options if there is no protocol?
This is when you usually revert to existing protocols, which however have not yet been used with the existing system and must therefore also be adapted accordingly. For applications within the railway sector, this also means taking into consideration the relevant standards and requirements. As the data transfer system is generally exposed to a diverse range of threats, it must be possible to identify the message errors listed in EN50159. In the past, countless standardised and proprietary protocols were developed that incorporated the corresponding security features. The standardised protocols, such as UNISIG, Subset-098 or RaSTA, are mostly very complex, with the result that implementation would give rise to considerable expense.
Proprietary protocols are available both in simple and complex forms. They have often gone through developments, which generate partly unnecessary overheads that are carried forward. Specifications may well be available, but these often lack additional matters that must be considered at the implementation stage. The main problem, however, relates to the entitlement to implement this protocol in the first place and then to use it.
So, the Frauscher Safe Ethernet FSE protocol was developed against the backdrop of these different options?
Yes indeed. The objective of the work on the FSE in the first instance was to develop a railway-specific software protocol. Based on UDP/IP, this facilitates communication between two points, thus satisfying the requirements in accordance with CENELEC SIL 4 and EN 50159 Category 2.
This significantly speeds up the integration of new components in various projects. Up to 201 bytes of application data can be sent in two directions via a safe transmission in cycles. Besides information of up to 40 counting heads or 80 track sections via just one communication board, this includes resetting information and I/O information from the interlocking to the communication board. Redundant board or network structures are also supported.
Why has Frauscher opted for the Ethernet format when developing this software protocol?
What clinched it for us was how widespread the format is: Ethernet is state-of-the-art and can be used as standard in most existing networks, with no additional hardware costs. With regard to use in the railway sector in particular, various benefits speak in favour of the Ethernet format. These include the extremely safe connection, which assures very high-speed data transmission – up to real-time transmission.
And the very stable connection ensures that virtually no data is lost. The vast address space allows for a large number of participants to have simultaneous access. Furthermore, it is also possible to transmit various data via a network where different data transfer media, such as cables, optical fibres and radio can be combined.
How does Frauscher make this protocol available to its customers and partners?
We have discussed this at great length, as we do not simply want to give away our newly acquired know-how without any thought. The unanimous decision in the end, however, was to make the FSE freely available for various applications. This is also in keeping with Frauscher's philosophy: Both parties should benefit from the open partnerships and collaborations with users – namely by exchanging information and practical use.
So far, the FSE protocol has been successfully implemented on four different PLC platforms. This made it possible for us to implement twelve customer projects for various applications. These solutions are now being used around the world. In 20 other companies, work has already started on implementing these solutions using additional hardware platforms. All in all, information relating to the protocol has so far been discussed with 80 interested parties to explore the potential in various applications.
And even though the protocol was specifically developed for transmitting axle counting data, its beneficial features have also enabled it to be used to transfer nonaxle counting data. We too are learning something with every new implementation.
To receive the freely available information about the FSE protocol, simply get in touch with us. Once details such as the intended purpose and any possible adaptations have been clarified, we can get started with the implementation work – together and with a completely flexible approach, but always strictly according to protocol.
The Ethernet format offers a range of benefits.
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