Can the legacy of fieldbus ever be replaced by industrial Ethernet?

While the fieldbus war may be over, the battle for industrial Ethernet vs. traditional fieldbus technologies is coming. The future looks strong for industrial Ethernet, but we probably aren't going to see the last of fieldbus for many years.

By Tom Moore, IHS Technology July 30, 2014

There is no doubt that the fieldbus wars had a resounding effect on industrial communications. The technologies they offered and the vast amount of press about them created a difficult environment to select just one, especially when many of them were standardized by the International Eelectronic Commission. While that war may be over now, the next battle is industrial Ethernet vs. traditional fieldbus technologies.

IHS Technology has been examining the markets for industrial Ethernet and fieldbus for over 13 years now. The latest edition of the study has recently published and the findings show a gradual move towards industrial Ethernet solutions. Although fieldbus outweighed Ethernet at approximately 2.7:1 in 2012 – Figure 1 shows the ratio of fieldbus to Ethernet nodes; this is forecast to decrease to approximately 2.1:1 in 2017. The use of industrial Ethernet is slowly increasing but it is likely to take many years before it overtakes fieldbus in terms of new node connections. Initial forecasts put Ethernet as being the predominant technology (greater than 51% of new nodes) in 2030.

Figure 2 shows the increase in the number of new Ethernet nodes vs. the decrease in market share of fieldbus technologies. Overall, this share is forecast to decrease slowly, despite a large number of new Ethernet nodes being implemented. This is because many more new fieldbus nodes are still installed each year than new Ethernet nodes-even though Ethernet is likely to become the predominant technology in the future. The legacy of fieldbus technologies remains extensive, having been around since the late 1970’s. And these older technologies aren’t simply going to disappear. Users of fieldbus technology, for instance, are advocates of their simplicity and reliability. This is unlikely to change without active engagement by automation vendors and protocol associations to promote Ethernet and the benefits of transitioning. Moreover, the use of these fresher technologies as the main source of networking is likely to be implemented only in newer plants and factories.

Process automation in particular is very fieldbus centric, with Profibus, HART, and Foundation Fieldbus standing out as leading technologies. The slow moving nature of process automation and high cost of facility upgrades mean that fieldbus solutions will continue to be widespread long time to come. The intricate and extensive wiring of process facilities, together with large scale, also mean that refits are a last resort. If the current networking backbone works then it’s very likely to be changed.

The huge legacy of fieldbus is somewhat of an issue in terms of new ideas and innovations. There is little room for innovation when users become comfortable (over many years) with what they’re using. There can be major backlashes from users when changes are implemented (Windows 8 and Microsoft’s reversal of removing the start button is a good example). Continued use of older technologies is obviously useful for users wishing to run a plant with existing, and knowledgeable engineers, but it does mean there is potential to miss out on the advantages that newer technologies offer.

Some of the latest gains in terms of factory efficiency and reduced down-time are best felt on industrial Ethernet networks. Power saving protocols, integrated safety, as well as aspects of ‘factory of the future’ can be implemented much more easily on Ethernet. Retraining engineers who have used the same technology for 30 years can be prohibitively difficult, however, so it often falls to younger engineers to promote the advantages of newer technologies.

One of the major trends seen by IHS during research was the buzz around "Industry 4.0" or "Smart Manufacturing". This next step in the evolution of the industrial environment revolves around several sub-trends including big-data, pervasive sensing, and mobility. Although it is still in its infancy, the concept is drumming up further interest in industrial Ethernet solutions, which in turn could potentially boost other trends leading to "Industry 4.0". Mobility also brings in the use of wireless communication, which is already most commonly used with process measurement devices. The ability to monitor and control many applications from anywhere in the facility will prove beneficial if the stigma over reliability and security can be overcome.

In the short term, fieldbus technologies are certainly suitable for many industrial applications. However, long term, industrial Ethernet will be more widely adopted, leading to efficiency gains, more flexibility, remote access, better diagnostics, faster networking and the ability to integrate the factory floor with the enterprise environment. Overall, the future looks strong for industrial Ethernet, but we aren’t going to see the last of fieldbus for many years.

IHS Technology has research teams focused on automotive, industrial automation, physical security, gaming, digital signage and cellular communications. Bringing together these industry experts, in turn, has helped provide for the first time a substantive overview of the size, penetration rate and forecast growth of the embedded vision market.

Tom Moore is an analyst with IHS Technology. He is part of the Industrial Automation group and focuses on the industrial Ethernet, fieldbus and wireless communications research. Tom is also responsible for the industrial communications quarterly index. Edited by Joy Chang, Digital Project Manager, CFE Media,