Arduino's Opta Family Gains a New Industrial Automation Capability: OPC UA Support

Arduino has announced a new string in its Opta programmable logic controller (PLC) bow: support for the Open Platform Communications (OPC) Unified Architecture, or OPC UA.

"OPC Unified Architecture – OPC UA in short – is a cross-platform, open-source machine-to-machine communication protocol for industrial automation. It was developed by the Open Platform Communications (OPC) Foundation and is defined in detail in the IEC 62541 standard," the Arduino team explains. "With the release of the Arduino_OPC_UA library we enable users to convert any product from our Arduino Opta range into an OPC UA-enabled device."

Arduino's Opta family, which sits at the heart of the Arduino PLC Starter Kit and the company's attempts to address the growing skills gap in the field of industrial automation, marked the company's entry into the programmable logic controller (PLC) market. Already supporting the full raft of IEC 61131-3 languages, plus the familiar Arduino IDE, the addition of OPC UA support covers a gap that may have previously kept the devices out of established industrial automation projects.

Based on Frauhofer's Open 62541 project, the Opta OPC UA functionality can be added to any model of Opta and provides access to analog and digital inputs, relay outputs, and on the Opta WiFi the user-programmable button and status LED. Any existing OPC UA system can communicate with an Opta and vice-versa, using the standard's binary encoding specification over TCP sockets — and the library can automatically detect up to two official expansion modules connected to each Opta and configure them.

"You can extend the default OPC UA server to add additional OPC UA properties such as data collected from a sensor device connected to the Arduino Opta," the Arduino team notes. "As a demonstration, we’ve created an example showing how to collect temperature and humidity data from a Modbus RTU device (connected to the Opta’s RS485 port) and subsequently expose this data via OPC UA properties."

The source code for the Arduino OPC UA library is available on GitHub under the permissive Mozilla Public License 2.0; instructions are included for compiling the firmware and uploading it to a connected Opta PLC.