Converging automation standards

Competing standards and protocols often cover the same ground but are not compatible, to the dismay of end users. Sometimes they can be brought together to benefit vendors and users.


Even a casual observer working in our industries will soon realize that there are many standards and protocols covering various aspects of hardware, software, and work practices. They cover safety, communication, form factors, and all sorts of related elements. It’s hard to imagine life without them as such standards ensure interoperability in ways we take for granted.

The darker side of this discussion emerges when two competing standards cover the same area but are incompatible. The classic example, if you’re old enough to remember it, was the development of competing VHS and Beta tape formats for home video recorders. These were developed in the 1970s originally by JVC and Sony, respectively, and did, for all practical purposes, exactly the same thing. If you wanted to buy a VCR back then, you had to choose one or the other. Sellers had to have both available. Tape rental stores had to have two departments with the same titles. Ultimately, natural selection pushed Beta out of the market. Let’s not think about how much money was wasted in the process.

This story has been repeated many times in industrial circles. A number of products and protocols have been relegated to the dustbin of history along with Beta tapes. At the same time, a handful of efforts have emerged in various areas to smooth over differences between competing standards and create something new that accommodates both. These are often driven by groups of users and even vendors interested in reducing pointless redundancy. Normally, the ultimate goal of such an effort is to structure the solution so that it has backward compatibility with equipment from either camp. This can often be a major technical undertaking.

The most recent example of how that has worked out positively is the development of FDI in an effort to bridge the gap between FDT/DTM and EDDL as device integration platforms. While the differences between these two approaches were fairly extensive, the group was able to create a new approach that is able to work with both. As vendors implement the new standard, users will not have to choose one or the other, or worse, duplicate efforts and support both.

Another area where some consensus would go a long way is wireless field device communication. In a 2010 Control Engineering article, Herman Storey, a process industry consultant and co-chair of the ISA100 committee, advanced this argument on behalf of users: “Proprietary technologies limit users’ abilities to select the best system, the best field equipment for an application, and the best integration of system and field equipment with reasonable engineering cost. Proprietary technologies may offer attractive features when working in a single vendor environment, but the downside of these features is their lack of general applicability and permanence. Users want interoperable standards-based products and systems. Interoperability needs a significant amount of support, but the payoff is improved risk management for vendors and users. Users are now demanding interoperable solutions (the ability to freely mix vendors) for industrial wireless technologies.”

While this is certainly a compelling motivation, sometimes these bridging efforts are not effective. In December, the ISA100 committee disbanded its ISA100.12 subcommittee that was trying to create a convergence of ISA100.11a and WirelessHART standards aimed primarily at wireless process instruments. While the two platforms are similar, no ideal technical solution that could work with both had emerged. The group also suffered from contentious differences between vendor representatives.

Disbanding this group does not mean such efforts have ceased. Another organization called the Heathrow Wireless Convergence Team continues its work as an open interest group dedicated to creating a single communication standard for wireless field device networks in process industries. The structure of the organization is more along the lines of the FDI Group, which is arguably better suited to this type of work than an ISA subcommittee.

Technical developments continue under this banner and now include WIA-PA from China in addition to the original two. A critical mass of users, vendors, and academic institutions is now behind the effort, providing the best hope for wide support. This is a critical first step, but it is only a first step in that creation of a convergence path has to launch development of a new standard. Writing standards is inherently a slow process which has to move on to the vendors for adoption. A 10-year time span is typical to move from formation to having products available for users.

The opportunities related to wireless deployments have been discussed extensively. Some users have decided to drag their collective feet and refrain from installing such systems until all these standards discussions have been finalized. With some unified effort and a little technical luck, maybe this one will gain some lost ground.

Peter Welander is a content manager for Control Engineering. pwelander(at) 

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