OPC UA PubSub for IIoT: The new 1.04 version of the OPC Foundation specification now includes the pub/sub communication model which is a better fit for Industry 4.0 and IIoT implementation work than the client/server architecture defined in the previous OPC UA standard.
PubSub is an attractive option for control systems and field devices
The new OPC UA PubSub specification makes OPC UA into an attractive option for control systems and field devices. For cyclic, deterministic data exchange, OPC UA now offers mechanisms that are comparable with Ethernet/IP or PROFINET RT. For this reason, Softing has expanded its OPC UA family to include an OPC UA Embedded Toolkit. The new “uaToolkit embedded” has been designed with embedded systems in mind that have little available memory and low computing power. As one example, the implementation of an OPC UA publisher with the uaToolkit embedded requires just 150 kB of flash memory storage for the code and static data, plus 10 kB RAM for runtime data. In comparison, implementing an OPC UA publisher with a Nano Embedded Device Server protocol-compliant OPC UA server requires 230 kB flash memory and 40 kB RAM. OPC UA also offers good levels of performance on embedded platforms. On a Raspberry Pi 1, a server implemented using the uaToolkit embedded is capable of reading or writing over 140,000 variable values per second. A test version, which can be used to evaluate development with the uaToolkit embedded on Linux and Windows, is available for download.