This is an attitude that I probably picked up during my career working on standards development committees. Some standards are designed for safety, some for efficiency and some for interoperability—that is, the benefit to the user of the products and technologies is to be able to use and integrate these products and technologies from a variety of suppliers with a minimum of pain.

There exist a plethora of kinds of standards. Some have a rigorous development process resulting in the blessing of or adoption by government or trans-government agencies. On the other hand, some standards are simply practices or technologies—some of which may even be proprietary to the developer—that everyone just picks up and uses. These are de facto standards. In another context, an industry chief executive once told me, “The best standards are de facto standards.” I took him to mean that these are standards that people actually use without waiting for official blessing.

To paraphrase singer Arlo Guthrie in “Alice’s Restaurant,” what I really came here to talk about is wireless. This is a technology that drew more ink in automation than anything since the days of “PC-based control.” There exist, of course, many types of wireless technologies already in automation. Human communication across large facilities—from refineries to automobile factories—was facilitated by such devices as “walkie-talkie” radios, pagers and then mobile phones. The industry battle lines first became drawn over the area of wireless sensor networks, and then expanded to include control of process loops and perhaps other input/output devices over the wireless networks.

Perhaps the greatest value to industry of the International Society of Automation (ISA) is its standards-setting activity. Its procedures are so rigorous that its standards are recognized by governmental agencies such as the American National Standards Institute (ANSI)—which is why you see the nomenclature “ANSI/ISA standard XXX.” So, ISA authorized the development of a committee to develop standards governing these wireless technologies for the process industries. Unfortunately, as sometimes (usually?) happens in standards committees, competing technologies championed by different industry-leading suppliers were proposed and battle lines were drawn.

A second standard

In the meantime, another group—the Hart Communication Foundation, owner of the ubiquitous Hart protocol used to transmit digital information of process instruments that also still use analog signals—went to work on a wireless standard. HCF also has a rigorous process that can result in recognition of its standards by the International Electrotechnical Commission (IEC).

The WirelessHart standard was issued first, and it was immediately embraced by some process systems suppliers as well as a large number of instrument suppliers. Then the ISA 100.11 subcommittee developed a recommended standard that has just passed through the remaining channels of the ISA process to be adopted by ISA and forwarded to ANSI for adoption (and probably IEC after that). This standard is different from the WirelessHart standard and each is championed by a different set of major systems suppliers.

It’s strange in that the final announcement of ISA100.11a was so terse that it seemed like an anti-climax. The net result for users is that there now exist standards to which suppliers can build products. The products should have the usual degree of interoperability, not to mention technical stability. This should give engineers the confidence to adopt wireless sensor networks and start reaping benefits of increased information at reduced cost of installation. So, even though there are now two standards, that’s probably not a bad thing for users. One would have been better, but now the battle can move to the market—where it counts.

Subscribe to Automation World's RSS Feeds for Columns & Departments