Online condition monitoring for PAT measuring devices at INVITE

Process analytical technology (PAT) is costly to maintain. PAT specialists make regular inspections on site at fixed time intervals.

Through remote access based on the NAMUR Open Architecture (NOA) principle, the status of the measuring device can be checked online and in real time using the vitality data. The costs associated with on-site inspection are eliminated and lengthy troubleshooting is no longer required.

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Online condition monitoring for PAT measuring devices at INVITE

Customer profile

INVITE GmbH is a private-public partnership between Bayer AG, TU Dortmund University, and Heinrich-Heine University Düsseldorf.

The INVITE subsidiary in the CHEMPARK chemical industry estate, Leverkusen, Germany

As a link between the life sciences industry and research, INVITE provides a platform for innovative projects in digital process and laboratory automation as well as in formulation development.

As part of INVITE, the Digital Showcase Center also demonstrates new technological approaches. It features demonstration systems for the NAMUR topics of MTP (Modular Type Package) and NOA (NAMUR Open Architecture).

Application

Together with Bayer AG and Lanxess AG, the partnership has identified online condition monitoring for PAT measuring devices particularly as an application that can benefit hugely from the NOA concept.

To test the technical implementation, a demonstrator was set up in the INVITE technology center. This demonstrator maps several pH measurements taken by devices from different manufacturers. In addition, the demonstrator was also equipped with the NOA IIoT server from Phoenix Contact.

The NOA test facility at INVITE in the CHEMPARK chemical industry estate, Leverkusen, Germany

Solution

However, through remote access based on the NOA principle, the status of the measuring device can be checked online and in real time using the vitality data. The costs associated with on-site inspection are eliminated and lengthy troubleshooting is no longer required.

Reliable extraction of system data

NAMUR Open Architecture (NOA) aims to generate greater benefits from existing system data. Particularly in older existing systems, the corresponding data is difficult to access. An interface for making the system data useable does not exist.

The NOA concept enables the standardized and secure export of the existing data from the current system. Often, the system does not have any modern interfaces. To take this into account, the classic automation pyramid is extended to include a side channel through which access-secure communication takes place.

In this context, the term “data diode” has been coined. Information can be extracted without anyone being able to penetrate the system.

OPC UA data exchange standard

A flexible and secure data interface has proven to be an essential building block for realizing the NOA concept. Open Platform Communications Unified Architecture (OPC UA) includes all the features needed for this. The standard aims to connect platforms via a unified architecture. This type of connection is often known as IT/OT integration, which to the field level (operational technology, OT) and the office area (information technology, IT) being coupled together. The OPC UA interface can be integrated just as well into a small field controller as it can into a complex enterprise tool. Because OPC UA can also incorporate numerous state-of-the-art security features, the standard is particularly suitable for the NOA concept.

Improved orientation with an information model

With such an information model, the OPC UA interface can be adapted in terms of the data structure and the namespace. The information model provides better orientation in the data because the structure and names are standardized. This is a significant improvement. The names of the pieces of information were not consistent before, because they were assigned individually by the sensor manufacturer, for example.

The information model for NOA is abbreviated to NOA IM. The OPC Foundation published the precursor PA DIM (Process Automation Device Information Model) in cooperation with the Field Comm Group. In the PA DIM, the basic information for each standard process sensor – such as temperature, pressure, and flow sensors – is defined in the form of a name and structure. NAMUR now adds additional information, thus extending the model to become the NOA IM.

Intelligent software for data collection

The NOA IIoT server from Phoenix Contact is a practical implementation of the NAMUR Open Architecture. In other words, it is intelligent software for our compact PLCnext Control field controllers. The server collects the information from the HART sensors installed in the field. The sensors often contain a variety of informative but as-yet unutilized data.

The NOA IIoT server connects to HART-compatible sensors over a HART gateway via a branch line. The individual devices are identified. The server uses the specific description file that is held available in a large pool. All of the information can be retrieved from the respective sensor and made available on the OPC UA server in a uniform format.

A remote I/O station from the Axioline P product family for process engineering systems will soon be integrated into the solution. This will enable the NOA IIoT server to communicate directly via the bus coupler.

PLCnext Control, OPC UA server, and HART gateway in a control cabinet

PLCnext Control, OPC UA server, and HART gateway for signal coupling

Extended definition of the vitality data

For the online condition monitoring application, specific values are required that are based on the respective measuring task. For this reason, the NAMUR Process Analysis Technology Working Group has defined what is known as vitality data for various PAT measurement tasks. This vitality data extends NOA IM. This enables the users to inspect process analysis devices via remote access based on the information transmitted. For example, the glass impedance, the impedance of the reference electrode, and the date of the last calibration are required for a pH measurement.

Alexander Wittenbrink and Thilo Glas in the INVITE test facility

Online condition monitoring application at INVITE

NOA test facility control cabinet with control and measurement technology

Timely availability of a device-specific description file

Realizing the online condition monitoring application on the demonstrator revealed that branching the HART signal off to the NOA IIoT server is challenging. The solution to this depends heavily on the individual situation in the brownfield. For many applications, however, using HART-transparent separators, which pass on the HART input signal transparently to two output signals, is sufficient. The integration of remote I/Os will enable further connectivity options in the future.

Summary Automated data structure export

Upon installing the NOA IIoT server and generating the description files for the INVITE demonstrator, the key advantage of a uniform information model was clearly evident. Despite using devices made by different device manufacturers, the data structure on the OPC UA interface of the NOA IIoT server is identical for all devices.

This structure can then be exported automatically to data histories or cloud applications. The PAT specialists can now call up all vitality data from the measuring devices via remote access. The values are sorted and prioritized in accordance with the NAMUR Process Analysis Technology Working Group and are available with a uniform syntax and semantics for all devices. It is possible to utilize these via trend analysis or other maintenance software. In addition, maintenance costs are reduced. Inspections are via remote access instead of locally. Maintenance plans are created to be event-based instead of time-based.

The next step is to collect vitality data in the production facility. This pilot project will thus be used to examine whether the selected vitality data proves itself in day-to-day operations. The aim is to adapt the NOA information model precisely to the respective application.

Alexander Wittenbrink - Invite GmbH, Automation Engineer