OPC DX: Specification to achieve candidate release status
Rockwell's PLC was left talking OPC DX to itself at Hannover.
Cleveland, Ohio, USA - The OPC Foundation's DX Protocol is to make its long awaited transition to Candidate Release status at the end of June, and will be available for public review and comment, according to Tom Burke, President of the OPC Foundation.
"It's been longer than we expected but it's better than we expected," he said.
He added that the OPC DX interoperability demonstration previewed at Hannover Fair would run again at the ISA show in Chicago (21-24 October 2002) with the three instigating companies, Rockwell Automation, Siemens A&D, and Emerson Process Management again joined by Phoenix Contact. Up to 10 more companies are making plans to participate, he said.
This promise must be compared with the disappointing demonstration at Hannover this spring. Of the four controllers mounted on the interoperability wall in the OPC Foundation stand, only the ControlLogix PLC from Rockwell had OPC-DX capabilities actually embedded in it, explained John Baier, Director of Software Architecture at Rockwell Software.
Vendor independent configuration tools may have been available but they couldn't be demonstrated without multiple vendors' hardware to connect to, he explained.
"The people that I feel have been let down are the Rockwell engineers who gave up their weekends and evenings to get a working DX demo ready with an ever moving specification. While we clearly demonstrated some interoperability between OPC DX implementations at Hannover, we would have preferred that our embedded OPC DX server had another embedded server to talk to. We look forward to this type of demonstration at the upcoming trade shows, because we believe that embedded OPC DX implementations will be the most useful in practice," said Mr. Baier.
"This time, the focus of the individual companies will have to be on delivery, rather than on spin," he continued. "Helmut Gierse of Siemens A&D has predicted real products this autumn. Rockwell Automation has yet to make a formal announcement but is expected to have the PC-based implementation, and their own configuration tool available during this calendar year. To maintain the credibility of this initiative these should be on show with no excuses, no PCs `behind the wall.'"
Mr. Burke says that users are starting to ask a number of challenging questions: what problems will OPC DX solve; how will OPC DX and OPC XML be merged together into a single application; what is the future for DCOM based technologies as Microsoft moves to .NET?
Hopefully the OPC Foundation will have some answers at ISA 2002.
Control Engineering Daily News Desk
Michael Babb, editor, Control Engineering Europe