Indeed, that seems to be where demons lie. “Our work is cut out for us — and it will not be easy,” declares Richard Caro, CEO of CMC Associates, Acton, Mass., and co-chair of ISA’s SP-100.12, the WirelessHART Convergence Subcommittee. He suspects, though, “that there will be enough resistance from the WirelessHART community that will force the changes to be made only in the ISA100 specification.” Translation: interoperability will be a one way street.
Karschnia also believes that ISA100 will fully embrace WirelessHART. After all, more than 24 million HART devices already are installed and many of these can benefit from WirelessHART. “It’s where the future is,” he notes, adding that the IEC just approved WirelessHART as a publicly available specification.
“Interoperability is very achievable and, in fact, is the cornerstone of both HART and WirelessHART,” says Helson. “I suppose that it depends on what ISA100 decides to do about incorporating WirelessHART into the ISA100 standards.”
Regardless of whether interoperability is uni- or bi-directional, Caro’s committee is laboring to incorporate the wireless portion of the latest HART specification. ISA has permission to use the HART information submitted to the IEC. “Now we can accomplish the chartered mission of the subcommittee 12 of ISA100, which is to perform a features comparison. We’ll look for differences and pay attention to only those differences that affect end-users.” He expects completion of the comparison by the end of 2008.
After that milestone, achieving functional convergence — which doesn’t mean there will be a single document — still will require time. “I think it would take, at minimum, nine months — probably, September or October of 2009. It will take that long to figure out how to do it [achieve convergence] and then write the first draft of that standard,” Caro predicts.
Standard finalization can’t be achieved before 2010, he believes. “Then, what we have will be a specification that will allow equipment to be manufactured to a WirelessHART standard that will be interoperable with ISA100-enabled equipment, which is also designed to be interoperable with WirelessHART,” says Caro.
“Interoperability is a must,” emphasizes Bondoc. “Otherwise, we will not realize the universal adoption that is one of the promises of wireless.”
An Unfettered Future
The current challenges certainly aren’t undermining end users’ interest in the technology. “There are big audiences for seminars and knowledge transfer. We’re at the early stage — where Foundation Fieldbus was in the late 1990s,” says Johnston.
But the momentum is building. After all, plants must grapple with ever-increasing pressures to improve equipment uptime, operational efficiency, environmental performance and worker safety. Wireless may signal a new way to achieve better results.