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What is not lovable is a standard that is a-building, when controversy clouds the issues, arguments grumble on, and useless light and heat are thrown off. Welcome to the currently unlovable standards situation in wireless communications for industrial use.

Of course, wireless for industry is just a radio. And controls these days are just computers. In the world where radios and computers play together, there are plenty of existing standards for all sorts of needs—ZigBee, Bluetooth, WiFi, to use their street names—but for various reasons, they have problems in factories. Some consume more power than is feasible for battery-operated equipment. Some invite highly problematic interference. Some require unwanted middleware or kludges to connect to automation. Some are just not reliable enough to handle industry (you would not, for example, want to use your cell phone to monitor a pressure vessel full of volatile compounds).

Fortunately, people are tackling the problem of wireless for automation. One effort is the WirelessHart communications standard, a fledgling that is recently out of the nest and learning to fly. And there is the ISA100 effort, still hatching.

WirelessHart, part of the Hart 7 specification of the Hart Communication Foundation, can be thought of as a vertical standard, one developed for a single automation protocol for process industry. At the moment, it is happiest when applied to devices that provide intermittent and more or less one-way sensor reportage. In contrast, ISA100 (more specifically ISA100.11a) in development by the Instrumentation, Systems and Automation Society (ISA) is horizontal—or more nearly horizontal—because it is being designed to meld various specifications into what ISA100 documents call “a family of standards.” This family will eventually cover such protocols as Hart, Foundation Fieldbus, Modbus, Profibus, Common Industrial Protocol (CIP) and more. It will eventually cover all automation needs, including closed-loop control. Further, it will be (or can be) applicable to both process and discrete manufacturing.

The strongest positive for WirelessHart is that it is done, having been ratified in September of last year. Fully and officially compliant devices will be available this year from ABB, Emerson Process Management, Endress+Hauser, Siemens and perhaps others. A second positive for those with Hart-compliant automation installations is that if it lives up to the promise, WirelessHart equipment will easily join any existing Hart network, no problem, no learning curve, no lost time.

On the other hand, the greatest promise of ISA100 is its one-standard-fits-all approach. If it can deliver on its promises, the benefit to end-users is huge, simplifying equipment procurement, reducing spares inventories, and cutting network installation and configuration time. A second promising note is that ISA100 has long actively solicited input from end-users, with a number of end-user members on various committees. When done (and if it is done right), ISA100.11a should have stronger standards as a result of this participation.

At the same time, negatives are inherent in each. A protocol-specific wireless specification such as WirelessHart raises the specter of competing specifications for every individual automation protocol still in use, new or old. The biggest drawback of this is potential fragmentation of vendor offerings—and the laws of production dictate that the fewer devices produced for a given protocol, the higher the cost per device. On the other hand, the overarching drawback of ISA100 is its ambitious attempt to be comprehensive. There is a chance that is has bitten off more than it can chew. And, there will be a lot of jawing and a lot of friction before everyone is equally happy (or equally unhappy but grumbling only slightly).

There are significant benefits to a standardized technology. Jim Reizner, corporate engineering, at The Procter & Gamble Co., the big Cincinnati-based consumer products company, puts it this way: “Take the 4-to-20 milliAmp (mA) standard, which is so ubiquitous that many don’t even recognize it as a standard. The 4-20 standard defines a lot more than just electrical current levels—it defines a multitude of aspects required to make systems and instruments from various vendors interchangeable. Think about it—when a 4-20 mA pressure transmitter from one vendor fails, what happens when technicians go to the storeroom to get a replacement? They need only make sure the replacement device meets the application requirements—things like pressure range, metallurgy, process connection method and so on.

“The tech does not need to make sure the 4-20 mA from vendor A is compatible with the 4-20 from vendor B,” Reizner notes. “This kind of interchangeability is defined by the ...