Apart from the large backward compatibility,the second conceivable improvement compared with classical fieldbus technology is that despite all proprietary modifications, Ethernet and, to a large extent, also the IP suite are being recognized as a technological basis for the new generation of industrial communication systems.
All approaches allow for a standard TCP/UDP/IP communication channel in parallel to process data communication.
Even the real-time Ethernet solutions (such as PROFINET, Ethernet Powerlink, EtherCAT, etc.) have such a conventional channel for configuration purposes.
The separation of real- and nonreal-time traffic is accomplished on an Ethernet MAC level with prioritization or time-division multiple-access (TDMA) schemes, together with appropriate bandwidth allocation strategies such as time-slotting mechanisms or token passing.
In such a parallel two-stack model, IP channels are no longer stepchildren of industrial communication but offer sufficient performance to be used for regular data transfer.
While this enables, in principle, the coexistence of automation and non automation applications on industrial Ethernet segments, the mixing of automation and office is not advisable for performance but, more importantly, for security reasons.
The value of this standard IP channel is rather to be seen in a simple direct access path to the field devices.
Therefore,the currently favored solutions for configuration tools(i.e., Extensible Markup Language (XML), Simple Object Access Protocol (SOAP), and, more generally, Web technology) can be consistently used.
This again does not mean that industrial Ethernet solutions are interoperable or use the same configuration tools, but at least, the basic principles are the same.
All this could have already been done with traditional fieldbus systems as well, and it certainly would have been done had particularly the achievements of the Internet and the World Wide Web been available in the early 1980s.
Thus, what we see today with the rapid evolution of Ethernet in automation can in fact be regarded as a second wave of fieldbus development, which takes into account all the technological achievements of the last decade and exploits them for field-level communication