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X20 I/O Implements OPC UA Pub/Sub

X20 I/O Implements OPC UA Pub/Sub

A new X20 I/O system bus controller from B&R Industrial Automation makes it possible to implement OPC UA communication from sensors to the ERP layer without using any interfaces, or a connected PLC. Using an OPC UA server implemented in the X20 system, any OPC UA client can request information about connected I/O modules and sensors, and can change or read the I/O points connected to it.

"Users are able to deploy basic I/O, a temperature module or a high-speed counter, and there is no need for a PLC to be able to turn devices on/off or monitor and retrieve data. Basically, users have a headless I/O system that can be used to retrieve information from sensors, or pass sensor data up to higher enterprise-level software systems," Derrick Stacey, solutions engineer, B&R Industrial Automation, told Design News.

A new X20BC008U bus controller functions as an OPC UA server and provides all information about connected I/O modules to OPC UA clients from any manufacturer including controllers, SCADA systems, ERP systems, or cloud applications. Production process data can be transferred using a single protocol, and, using the new publish-subscribe model (Pub/Sub), data can be distributed in a very efficient manner. The bus controller can be used with all controllers and I/O modules from the company's X20 and X67 product lines.

The system doesn't provide real-time performance because TCP protocol used to implement OPC UA is not deterministic. But if that is not a requirement, users can wirelessly easily connect to field-deployed I/O racks and the possibilities are endless. I/O and sensor data is easily accessed without requiring a connection to a PLC, and users can communicate using wireless Ethernet technology.

"Implementing the OPC UA server not only provides Big Data but more importantly smart data because users can pick and choose selectively the information they want," Stacey added. "They are able to turn I/O on and off, and monitor system performance. With Big Data, accessing more information makes it possible to see patterns but it also requires a lot of computing power to sift through it all."

OPC UA Pub-Sub Messaging

"The OPC UA protocol communicates using a TCP stack which is very lightweight," Varad Darji, a senior product engineer for B&R said. "Basically any device that has implemented a TCP stack and has the ability to communicate using the OPC UA protocol can access the server. The OPC Foundation has made it effortless by providing the OPC UA stack which has been implemented by hundreds of software manufacturers."

The goal of OPC UA has always been to provide a multi-vendor, multi-platform and offer secure, reliable, interoperable communications that can be used for moving data/information from the embedded world to the enterprise. In April 2016, the OPC Foundation announced support for the addition of the publish/subscribe messaging pattern to the OPC UA specifications, and the first live demonstration featuring multiple vendors at this year's Hannover Fair.

The addition of publish/subscribe functionality to OPC UA provides the necessary infrastructure to achieve seamless interoperability for IIoT, IoT, and Industry 4.0 applications and devices. OPC has been based on a client/server architecture, but now the architecture provides a solid infrastructure that allows information integration from embedded devices to the cloud.

The OPC Foundation says it is working currently with more than 40 international suppliers that are developing products and solutions for the IIoT and needed to provide publish/subscribe to the technology portfolio to facilitate high-performance, highly reliable device application connectivity for this important market. Existing applications already using OPC UA client/server communications can add the publish/subscribe features with minimal effort.

Al Presher is a veteran contributing writer for Design News, covering automation and control, motion control, power transmission, robotics, and fluid power.

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