OPC UA Do you actually know what IT is doing in your production?

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Digitalization means more and more IT in production environments. This creates new dependencies. Because only if the IT works reliably, does the production run smoothly. But do you know if your IT components are currently functioning? Fortunately, there is OPC UA.

Johannes Liegert is the Product Manager for Industry and IoT at Paessler AG.

In the past, everything was simpler; machines were analog, and IT had no place in production. Then came digitalization, namely Industry 4.0 and with it IIoT, introducing promising innovations like Digital Twins or Predictive Maintenance. Everything was supposed to get better and much more efficient. However, the digital revolution requires IT.

Industrial PCs (IPC) now control production facilities, networks transport data, and older systems are integrated into the new digital reality through retrofitting. For all this to function, all components and processes must be constantly monitored, both those from the OT world and from IT. Systems for this already exist, as machines, IT networks, and infrastructures have always been monitored; however, this was done by different systems. In the OT world, these were control rooms: screens and control panels that monitor and control individual production lines or even entire industrial plants. When there were disturbances, lights would blink, and the responsible technician would go and resolve the issue.

Today, systems like SCADA or MES are the standard: software-based solutions that integrate or replace traditional control rooms. In the OT world, data is captured using industrial protocols and methods such as Modbus, MQTT, or OPC UA, transported over the production network, and processed. In IT, monitoring tools take over the surveillance. Using IT protocols like SNMP, HTTP, or NetFlow, information on the availability and performance of IT components and systems is collected, analyzed, and communicated. Here, the range of offerings is diverse and extends from manufacturer-specific tools to solutions for specific tasks like network performance monitoring or availability monitoring, to comprehensive solutions that monitor the entire IT infrastructure and beyond.

How do IT and OT come together?

In many companies, the monitoring systems for OT and IT are still separate. This separation makes it difficult to monitor cross-sectional processes and to identify the causes of disruptions. One approach is to teach IT monitoring systems industrial protocols. For instance, Paessler PRTG, a classic IT monitoring solution, now also supports industrial protocols and methods such as Modbus, OPC UA, or MQTT, allowing it to integrate machines and systems from the OT environment into a comprehensive monitoring framework.

However, an IT monitoring solution is designed for IT environments and IT specialists. While it is possible to integrate monitoring data from production facilities, relate it to data from the IT environment, and then publish it on dedicated dashboards for OT managers, this does not solve the fundamental handicap of specialization: only experts know what and how to monitor within their area of responsibility. This means that OT specialists set up the monitoring of the production environment and IT specialists handle the IT side. This requires both parties to use a solution optimized for their respective application area, one that they are familiar with, and metaphorically speaking, where the buttons are located where they expect them to be.

When OT and IT specialists work closely together in a team, the solution just described, namely an IT solution that can also process OT information, can certainly be an option. However, the larger the company, the higher the likelihood that responsibility for IT and OT lies with different departments.

This means that IT specialists often do not work in the production control room; possibly not even within the company—if the IT is outsourced to a service provider, which is relatively common in the context of IT in production environments. Outsourcing the monitoring of machines and production processes to an IT service provider, who then communicates the results to OT experts through appropriate displays, would be counterproductive. There is a lack of expertise about the production processes, the extra effort for knowledge transfer during ongoing operations would be too high, and the OT monitoring would be too indirect. The goal here is to integrate the information on availability and performance of IT components relevant to production into the OT monitoring, namely into the SCADA system or the control room. But how do we get the IT data into the SCADA system?

OPC UA as an intermediary between the worlds

OPC UA, which stands for Open Platform Communications Unified Architecture, is an industrial standard for data communication between various devices and systems in production. It enables seamless integration of machines, equipment, sensors, and other devices in a production environment and provides secure, reliable, and interoperable communication through a standardized interface for the exchange of data between different systems and applications. This is independent of the manufacturer or platform used. It includes real-time monitoring of machinery and equipment, remote maintenance and control, as well as the integration of data from various sources into a central control system. Additionally, OPC UA offers a high level of security by supporting encrypted data transmission and authentication.

OPC UA is well-suited for moving data in production environments, as well as for exchanging data between IT and OT environments. Specifically, Part 9 of the OPC UA specifications, "Alarms and Conditions," makes OPC UA a method well-suited for dynamic handling of alarm messages across different areas. An additional argument for using OPC UA is its capabilities for data encryption and authentication. Security plays a crucial role in opening OT environments to IT because it introduces new potential vulnerabilities that were not a concern for completely isolated production environments in the pre-digitalization era.

An overview of IT and OT is possible—and necessary

We now have three components for our comprehensive overview of a digitized production environment:

• A SCADA system or control room, where OT managers can find all information about their production environment and which enables the control and management of the same;

• an IT monitoring solution that monitors the network and other IT components;

• a method, OPC UA, that enables data transfer within the OT environment, as well as between IT and OT.

We could now transmit IT data via OPC UA from the IT monitoring solution to the SCADA system, thus enabling complete monitoring of the digitized production environment including all OT and IT components. However, there is still a small obstacle we must overcome: IT monitoring solutions typically do not speak OPC UA. Some solutions, like those from Paessler, do understand OPC UA and can receive data via OPC UA. But they do not speak OPC UA and therefore cannot directly transmit monitoring results to SCADA systems and control rooms around the world.

Thus, we arrive at a fourth component: an OPC UA Server—at Paessler, this is a new, standalone extension to PRTG. The software serves as a translator between the monitoring solution and the SCADA system or control room. More precisely, the Paessler PRTG OPC UA Server does not translate, but instead receives IT information and alarms, formats the received data in compliance with OPC UA standards, and sends it on to the corresponding systems on the OT side. Thanks to OPC UA Alarms and Conditions, the standalone solution can not only send alarms but also acknowledge them. This ensures parity of information between IT and OT teams, which allows for quick detection of disruptions, immediate identification of the source of errors, and clarification of responsibilities. Only in this way can disruptions of production processes, which include both OT and IT components, be promptly resolved, preventing serious consequences and failures.

“This article was first published on our sister portal "MM MaschinenMarkt" (German Edition), Vogel Communications Group.“