Representative End User Clients
Representative Automation Clients
Representative Software Clients
The Object Management Group (OMG) and the OPC Foundation announced a collaborative strategy for market and technical interoperability for two standards for the Industrial Internet of Things (IIoT). The OMG and OPC Foundation have developed a technical positioning and FAQ document for usage of both the OMG Data Distribution Service (DDS) standard and the OPC Unified Architecture (OPC UA) standard.
The positioning document explains that the DDS and OPC UA standards are largely complementary and compatible. Both are important to the future of the IIoT. The document is a joint recommendation designed to help companies implement an IIoT strategy.
The Standards
OPC UA is an industrial communication architecture for interoperability between sensors, field devices, controllers, and applications at the shop-floor level in real-time as well as between the shop floor and the enterprise IT cloud. OPC UA helps to allow SoA-based "plug and produce" scenarios. The information about the system, its configuration, topology, and data context (the metadata) are exposed in the collective "address space" of the individual OPC UA servers. This data can be accessed by authorized OPC UA clients that can see what is available, and choose what to access. OPC UA is designed so as new networking technology is developed, it can be plugged into OPC UA in a "plug & play" fashion. Client/Server, Pub/Sub and cloud protocols are integrated into OPC UA.
DDS provides location transparent, real-time data sharing across multiple networks. DDS lets applications define and share user data with controlled "Quality of Service" (QoS). DDS hides network topology and connectivity details from the application, providing a data-sharing abstraction that scales from local area networks to fog and cloud computing. It can support large fan out and sub-millisecond latency. DDS defines a "common data-centric information model", so that applications can run "plug & play" with minimal deployment configuration. System configuration details are deemphasized to help ease redundancy and interoperability.
Today, there is little overlap between DDS and OPC UA in applications. Even when used in the same market (e.g. energy) the use cases are different. OPC UA provides client-server interaction between components, such as devices or applications. DDS is a data-centric "bus" for integration and peer-to-peer data distribution. Because the focal applications and approaches for DDS and OPC UA are different, most applications fit better with one or the other.
The OMG and OPC Foundation are working together on integration and have developed two ways for the technologies to work together. First, an "OPC UA/DDS gateway" will permit independent implementations to work together. Second, "OPC UA DDS Profile" will enable integrated use cases. Both are in active development. By working together, the DDS and OPC UA communities will provide a non-proprietary path to interoperability, regardless of the customer's choice of starting technology.
This information was released by the standards development organizations responsible for both standards (OMG and the OPC Foundation), and supported by two consortia using the standards (IIC and Industrie 4.0). It is a cooperative result of their joint drive to help further enable the IIoT.
Keywords: Industrial Internet of Things (IIoT), Shop Floor, IT Cloud, Data-Sharing, IIC, Industrie 4.0, ARC Advisory Group.