John Rezabek is a process control specialist for ISP Corp., Lima, Ohio. Email him at [email protected]You've probably heard by now that there's been a merger of fieldbus protocol foundations representing HART and Foundation fieldbus (FF). After 2014, there will no longer be separate foundations governing the HART and FF protocols. There will be one group, one board of directors and one president.
But news of the merger has also created speculation and outright dreaming. One end user asked Chuck Micallef, marketing director for the HART Communication Foundation, "Will this mean I'll be able to use my HART device for Foundation fieldbus?" Sadly, such dreams will have to be left on the pillow. We may sooner see interoperability between WirelessHART and ISA 100.11a. So why won't HART and FF beget an even cuter and more lovable protocol like a Labradoodle of buses?
HART and FF do indeed share a lot of the same DNA. That's one of the reasons the merger makes a lot of sense. Back in the days of the enhanced electronic device description language (EDDL) cooperation group, it was often heard, "When we looked at HART, FF and Profibus PA, we found we had 97% of parameters in common." Humans are said to share 99% of their DNA with chimps and bonobos, too. While we don't expect any chimps to be boarding the bus with the kids in the morning, the three aforementioned protocols merged their DD languages into a single IEC standard a few years ago. Why would these three protocols have this much in common to begin with?
Also Read: Fieldbus Foundation and HCF Make Progress towards Potential Merger
[pullquote]While we may think of the communication technologies as separate "houses," they are, in fact, composed of nearly the same member companies. I can count on one hand the suppliers that don't have an offering in at least two of the major protocols, if not all three. Most of our favorite suppliers belong to all three clubs, and the disparate technologies really are fueled both intellectually and financially by the members of each club, so we shouldn't be shocked or amazed when similar features emerge from all three protocols.
On the system side, the economies of convergence can be even more compelling. A site can easily find itself employing multiple protocols, from HART and Modbus to DeviceNet, EtherNet/IP, Profibus and Foundation fieldbus. All these are integrated—or not—into what's often a single host or asset management system. An abundance of intelligence and features on the device side are "stranded" if there are no services on the system side to interpret, organize and display the useful insights and diagnostics to thinking humans. Having greater uniformity between a few of these more common protocols can only help system developers deliver new features. The folks at FDT group point out, "a single frame application supports HART, Profibus, Foundation fieldbus—and others coming soon."
Which brings us to the FDI Cooperation, the latest joint venture between HART, Foundation fieldbus and Profibus PA, which also includes the FDT Group and OPC Foundation. (FDI stands for "field device integration.") By deploying a unified standard for the integration, configuration and management of assets used in process control, FDI aims to make the delivery and utilization of smart assets/devices easier, more uniform and more economical for both suppliers and end users.
Many of the same engineers have been showing up at the same meetings and on the same expense accounts, and the supplier companies who largely foot the bill for these non-profits wondered why they belonged to so many clubs. With HART and Fieldbus Foundation both headquartered in Austin, Texas, the logistics and legal hurdles were low enough to make the merger compelling. That's why it's happening.
Next year, they'll be under the same roof. So why won't the HART device speak FF? While the HART device may incorporate many of the same diagnostic capabilities of its seemingly identical FF kin, the protocols are fundamentally different both in philosophy and use. Next month, we'll explore the main distinctions in a little more depth.
