up until recently, OPC UA has successfully positioned itself as a standard for vertical communication. Due to its design, meeting real-time reqs was out of scope and therefore the standard didn't compete with field-level protocols/busses such as Profinet, EtherNet/IP etc. Since the demonstration of OPC UA PubSub over TSN showed that deterministic communication with OPC UA was possible, I have wondered if this stack might in the future be used for machine-internal communication as well.
Do you guys think this might happen? Are there any fieldbus capabilities that OPC UA PubSub TSN misses?
The OPC Foundation has started several activities - TSN working group in 2015, Safety working group in 2017, Field Level Communications (FLC) Initiative in 2018 - in order to extend the OPC UA framework to cover additional requirements for applications in process and factory automation. An important extension to the OPC UA framework in this context is to include deterministic communication by applying Ethernet TSN, Ethernet-APL/SPE and the IEC/IEEE 60802 Industrial Automation (IA) TSN Profile (selection of TSN features) which is currently under development. However, to cover all the requirements of an industrial communication solution for the field level (comparable to Profinet and Ethernet/IP), additional features have to be specified: e.g. device-specific semantics for the various devices & applications (motion, safety, remote I/Os, …) and concepts for configuration & bootstrapping. Such specifications are being developed by the FLC initiative, which will target in a first step C2C (Controller-to-Controller) use cases, and then extend these concepts to C2D (Controller-to-Device). It will take some time to finalize the work, but significant progress has already been made (e.g. a first Safety specification has already been released, the first specification release for C2C to be expected later this year).
The big advantage of bringing OPC UA to the field level is that - in contrast to other pure fieldbus protocols - OPC UA scales from the sensor across all levels to MES / ERP and also into the cloud – with integrated IT security, which has been planned in from the start.
Please join the free of charge OPC-Day on June 23-25.June to get a 1h update on the OPCF-FLC initiative.