The OPC Foundation, a not-for-profit, multi-vendor organization devoted to solving the connectivity problems of control technology through open standards, celebrates its tenth anniversary this year. That milestone brings with it another: the organization's most significant specification to date -- the OPC Unified Architecture (UA). OPC-UA, which will provide a framework for connecting the factory floor to the enterprise, is due out in its final form this summer, with the first compliant products ready in the fall.
The OPC Foundation was started in 1996 by a handful of engineers who set out to solve the device driver problem in industrial control. The foundation has signed 400 members to date. From the start, the group's humble goal was to "keep things simple," notes current OPC president Tom Burke. The first specification born of that mantra was OPC Data Access (DA). Using Microsoft COM/DCOM, it leveraged a simple object model that allowed any PLC to communicate with any HMI without writing custom drivers. Over time, the specification expanded to address alarms, events, and security functions, and eventually added XML capability to allow connectivity across corporate firewalls.
Even as the specification evolves, however, manufacturers' investments remain protected. "One of OPC's claims to fame is that the applications developed in 1996 will work with new products developed in 2006," Burke says. "From a developer's perspective it can be frustrating, but it is a commitment we made to the end users that once you bought an OPC server, an OPC client should be able to talk to it no matter what."
As a result, support of OPC has skyrocketed. Burke estimates there are about 3,000 companies building OPC products. "And that doesn't count all of the companies that are using OPC in ways we never dreamed," he says, noting one large automotive company that leveraged an OPC interface on top of ODBC, a standard database access method.
"OPC never was a true standard, but the adoption rate has been phenomenal," says Craig Resnick, an analyst at ARC Advisory Group (Dedham, MA). According to an ARC 2004 Plant Connectivity report, 60% of those surveyed said OPC was the preferred plant connectivity choice for control systems, and 70% of respondents use OPC for HMI/SCADA connectivity. "To this day, there is no specification number, but people refer to it as a standard because it is so commonly implemented," Resnick says.
Burke acknowledges that OPC has always been a de facto standard, but the introduction of OPC-UA will formalize that. Work is currently underway to make it an International Electrotechnical Commission (IEC) standard, which is a way to garner international recognition, he says.
Over the years, the OPC Foundation has aligned itself with many different groups -- from the Fieldbus Foundation to EDDL and FDT organizations, and, most recently, PLCOpen and a collaboration with MIMOSA to create the Open Operations & Maintenance (Open O&M) initiative. But perhaps the greatest accomplishment of the OPC Foundation, Burke notes, is the spirit of collaboration that has united the fiercest of competitors. OPC-UA, specifically, requires that vendors share intellectual property on proprietary architectures.
"OPC is about people working together. That is what has made it so successful," Burke says.
This article originally appeared in the May 2006 issue of Managing Automation magazine.