OPC UA – A Complete Solution for IIoT Communications

We are Ocean Data Systems, makers of Dream Report – the “Industrial” solution for reports and dashboards. When selecting interfaces for secure connectivity to data sources across the internet, our first choice for Dream Report was OPC UA.

Background

You have probably known of OPC for many years. Its history began back in the mid 1990s, leveraging then “new technology” COM and DCOM. The OPC Foundation strives to deliver a complete solution that would enable vendor agnostic interoperability. There are many different forms of data; real-time values, Alarms and Events, and repositories of history information. The OPC of the 1990s addressed these data types with different specifications; OPC DA, OPC AE and OPC HDA, among others.

Proving interoperability between vendors was addressed through test applications, OPC meetups, and Certification Tools, where vendors could bring products and test on a common network. Again, the key was to deliver interoperability between all vendors and products without the need for vendor specific integrations. OPC Classic, as the original specifications have been come to known, is still the connection of choice today for single computer and Intranet applications (the latter being somewhat more complicated with the need to configure and support Microsoft’s DCOM).

OPC UA for IIoT

We are now in the Internet age and there are additional standards to leverage for connectivity. OPC has evolved again to leverage the latest technologies, industry practices and learn from the past. Over 10 years ago, OPC UA was introduced as a unification of the previous specifications into one new architecture, leveraging today’s best available technologies and design practices. No longer based solely on Microsoft operating system technology, OPC UA delivers an architecture appropriate for the Internet age, delivering modern transports, security technologies and data and transaction specifications. The last two items are the key to a complete solution and were the defining criteria for its selection as an IIoT (Industrial Internet of Things) ready Dream Report interface. There are alternate IoT Protocols such as MQTT, AMQP, CoAP among others, but many only define transports and not data structures. It is like being able to phone another country, but not speaking the right language over that connection.

Easy to Use

Supporting OPC UA in a product isn’t that difficult and there are plenty of toolkits and sample code to help with the effort. You can learn much more by visiting the OPC Foundation website. In our case, developing an OPC UA client driver was accomplished using OPC Foundation sample code and accompanying documents.

Dream Report now includes an OPC UA implementation for real-time data access. That means Dream Report can act as a client to poll data from remote data servers, even securely across the Internet. The most common Servers to be used with Dream Report, and ones we’ve tested with are Kepware’s KEPServerEX and Software Toolbox’s TOP Server. The connection between the two OPC UA products and Dream Report is very straight forward. You may specify one or more Server Endpoints, letting you have different and secure connections for different external clients. You need to identify the IP Address of the Server, the Port to use, the encryption level and the User and Password. When using encryption, you will also need to transfer security certificates to enable the secure and approved communications between your various clients and servers.

In this image, you can see two Endpoint definitions in KEPServerEX that are easily set up with the Add Button.

KEPServerEX offers the ability to select and Trust connecting Client applications.

On the Dream Report side, you would specify the Server Endpoint and set up matching levels of security. Once the connection is established, Dream Report can browse tags, access and log data as necessary for Reports and Dashboards. (Settings below are for demonstration purposes only and it is always best to enable encryption and define named users.)

Summary

While there are more and more and more options for IIoT connectivity, OPC UA is a very straight forward solution that already offers a great deal if industry support and has been proven in real-world applications. For a list of OPC UA compliant products, visit the OPC Foundation Product List.

Roy Kok
VP Sales & Marketing
Ocean Data Systems