The OPC Foundation (OPCF) announced Nov. 8 that its Field Level Communications (FLC) Initiative has released the first set of OPC UA Field eXchange (UAFX) specifications. These lay the groundwork for using OPC UA for open, secure communications at the field level. Four years in the making, UAFX specifications have passed in-depth OPCF member reviews and extensive prototyping to ensure their implementations maintain cross-vendor interoperability. They allow automation vendors to adopt UAFX functionality in their products, and let end-users look forward to the advantages UAFX-based field communications.
UAFX specifications consists of four parts focused on exchanging process and configuration data between automation components. The parts use OPC UA client/server and publish-subscribe (PubSub) extensions in combination with peer-to-peer connections and basic diagnostics. The four parts are:
- Part 80 (OPC 10000-80) provides an overview and introduces the basic concepts of using OPC UA for field level communications.
- Part 81 (OPC 10000-81) specifies the base information model and communication concepts to meet factory and process automation's various use cases and requirements.
- Part 82 (OPC 10000-82) describes networking services, such as topology discovery and time synchronization.
- Part 84 (OPC 10000-84) defines the controller profile with details to fulfill conformance requirements.
The foundation reports this release lays the foundation for upcoming specification extensions, which will address controller-to-device (C2D) and device-to-device (D2D) use cases, as well as development of application profiles for motion control devices, field instruments, and I/O peripherals.
Demonstration at SPS event
At the recent SPS show in Nuremberg, the OPC Foundation showcased a multivendor UAFX-based interoperability demonstration comprised of automation components from 20 manufacturers, including ABB, Beckhoff, Bosch Rexroth, B&R, Emerson, Festo, Honeywell, Hirschmann/Belden, Huawei, Keba, Kuka, Mitsubishi, Moxa, Omron, Phoenix Contact, Rockwell Automation, Schneider Electric, Siemens, Unified Automation, Wago and Yokogawa.
The exhibit demonstrated horizontal communication between third-party controllers, such as controller-to-controller (C2C) communications. Utilizing the UAFX extensions, the controllers share process data using UAFX Connections and PubSub mechanisms via UDP/IP over wired Ethernet, Ethernet TSN and 5G wireless connections. UAFX connections use UAFX publisher and UAFX subscriber functions, and the controllers are configured and interconnected via built-in or standalone UAFX connection manager software. Siemens and Unified Automation implemented the UAFX connection managers used in the demonstration. The controllers in this demonstration are monitored in real time via a central dashboard, which visualizes the status, selected process data, and other information from the UAFX asset information model for each automation component.
"We’re happy about the progress that our working groups have made over the last months,” says Peter Lutz, field-level communications director at the OPC Foundation. “The publication of the first UAFX specification release and an impressive multivendor live demo are major achievements because the specifications are now mature so that real products can be implemented and conformance tests can put into place."
Since the start of OPC’s field-level communications Initiative in November 2018, more than 320 experts from over 65 foundation-member companies have contributed to generating the technical concepts and elaborating the specification contents for extending the OPC UA framework for field-level communications, including determinism, motion, instrumentation and functional safety.
"Big congratulations to all involved in these specifications. OPC UA already serves as a communication backbone in several process and factory automation initiatives due to its versatility, security and vendor independence," says Stefan Hoppe, president of the OPC Foundation. "As a first step, the UAFX extensions close the gap of standardized horizontal controller-to-controller communication, and will be referenced by many other organizations as a base technology foundation."
