What makes a system open?

In the recent Control Engineering Webcast, “Bridging Gaps with Wireless,” one participant claimed another's wireless system was an “integrated but closed architecture.” While fisticuffs were avoided on air, it did prompt moderator Peter Welander (Control Engineering process industries editor) to consider what makes a system “open.

By Control Engineering Staff December 1, 2008

In the recent Control Engineering Webcast, “Bridging Gaps with Wireless,” one participant claimed another’s wireless system was an “integrated but closed architecture.” While fisticuffs were avoided on air, it did prompt moderator Peter Welander ( Control Engineering process industries editor) to consider what makes a system “open.”

Welander asked two individuals what they think makes something open: Jeff Becker from Honeywell Process Solutions and Ron Helson, executive director of the HART Communications Foundation, a group founded on interoperability.

“Open systems may be one of those terms where different people may have different interpretations,” said Becker. “When I talk about open systems in the context of computer systems, I am referring to using well-known and widely deployable system interfaces that allow for interoperability with products from other vendors. The advantage of open systems to users is that they can integrate and combine elements of a system from different vendors, which prevents vendor lock-in. There is also a larger talent pool available that knows how to work with these interfaces. This ultimately lowers cost and improves choices through competition.

Becker said he considers Honeywell’s OneWireless an open system because it uses well-known and widely deployed interfaces like Ethernet, WiFi, and Modbus. “It passes IP traffic across the mesh in conformance with IP networking standards, and can be managed with network management tools that use typical SNMP protocols,” he said. “We make our sensor radio hardware and software available to any vendor at reasonable cost today, and we are migrating towards ISA100 Standard sensor interfaces in the future. Any vendor can therefore design a product that will work with our system, and any user can buy products from multiple vendors for use in their OneWireless network.”

Helson explains that the HART Communication Protocol (which includes WirelessHART) is an open communication technology. “An open technology is one that is not owned by one company, but is openly available to anyone who wants to use it,” Helson said. “The HART Protocol standards are well documented and available to anyone who wants them,” to understand the details or to implement the technology in products. The HART Protocol became an open communication technology in 1990, and the HART Communication Foundation was founded in 1993 to establish and administer programs that ensure the technology remain openly available for the benefit of industry.

“The HART Communication Foundation provides a full range of services to support the technology and ensure the compliance of products around the globe…. Any company (supplier, systems integrator, end user, educational institute, government agency) interested … can join the Foundation.”

To view the Webcast , visit www.controleng.com , click on the “Webcast” tab in the multimedia box in the upper right hand area of the home page, click on “View All Webcasts” and then select the “Bridging Gaps with Wireless” Webcast.