OPC for embedded applications
OPC interoperability has brought connectivity to many things; next efforts may include embedded controllers, human-machine interfaces (HMIs), and programmable logic controllers (PLCs), Thomas J. Burke, OPC Foundation president and executive director, told Control Engineering during a recent Make2Pack ISA88 Part 5 committee meeting.
Burke, who joined the Part 5 committee in the home stretch toward a final draft, said, “We weren’t thinking about embedded applications when we started OPC UA, and we had to make a few subtle changes to accommodate [them]. That includes removing or limiting security to create less overhead, and allowing for client-server arrangements.”
Burke ponders a future with a whole lot more interoperability, where Profibus and Fieldbus Foundation architectures could merge, field device translation (FDT) and electronic device description language (EDDL) unify, and different manufacturers’ PLCs interchange programming without translation. Many hoped IEC 61131-3 would lead to interchangeable PLC programs, but that never quite made it.
Filling in the divisions among many of these areas, Burke hopes, will be companion specifications to OPC UA, which would create a full XML schema describing data, metadata, and information. Mapping to physical devices can happen with help from domain experts and many vendors have expressed interest, Burke says, including Beckhoff, B&R, Emerson, GE Fanuc, Invensys (via Wonderware), Rockwell Automation, and Siemens. Organizations and groups interested include ISA88, ISA95, MIMOSA, PackML, and PLCopen.
Certification and many other efforts underway are expected to help, Burke suggests. Stay tuned. First cut at some templates may come as early as June.