PA-DIM Bridges the OT/IT Process Data Chasm

PA-DIM technology simplifies and streamlines the transport of valuable data from process plants to enterprise computing resources.

Advances in communications, digital technologies, and open architectures provide a wide range of interconnectivity options for process and manufacturing industries, but also introduce challenges to establishing and maintaining smooth communications throughout a company’s operations. A Control Engineering September/October 2024 article by FieldComm’s Paul Sereiko titled How to Use PA-DIM to Improve OT/IT Process Data shows how it is possible to standardize connectivity from field devices, up through plant networks and control systems, and on to enterprise computing systems.

Traditional automation data flow strategies and hierarchies have been rigid and resource intensive. Greater availability of field-sourced data, especially from intelligent instruments and systems, is driving the need for streamlined communications from the operations technology (OT) realm up to information technology (IT) resources as part of digital transformation and OT/IT convergence initiatives. This need is being partially met by modern internet of things (IoT) communications, but obstacles remain.

Evolution and Current Challenges

Recognizing the need for improved communications, FieldComm Group and the OPC Foundation in 2017 began to specify the Process Automation Device Information Model (PA-DIM). As part of a comprehensive digital automation architecture, PA-DIM standardizes connectivity and data representation from OT-based field devices (using protocols such as FOUNDATION Fieldbus, PROFIBUS, HART, and others), up through plant networks and control systems, and securely on to IT-centric enterprise computing systems (primarily using OPC UA). The discrepancy between OT and IT protocols, data structures, and other requirements necessitates a semantic standard to ensure clear communication between OT and IT systems.

The Role of PA-DIM

As end users undertake digital transformation projects, an important organization is NAMUR, which has published Recommendation NE 175 titled “NAMUR Open Architecture – NOA Concept” to introduce the concept of a monitoring and optimization (M+O) domain. PA-DIM is a technical underpinning of the NOA M+O concept, and it is used to standardize data semantics using existing IEC standards such as IEC 61987, which defines data structures and common data dictionaries. PA-DIM transforms OT data into a format easily understood by IT, facilitating tasks such as analytics, process optimization, and predictive maintenance.

In summary, the PA-DIM model provides an avenue for IT systems to easily achieve read-only integration directly with field devices—which may support different automation protocols—exposing the necessary data with full contextual semantics.

PA-DIM is a new information architecture providing a transparent and traceable way to uniquely identify instruments and their multiple signals in the context of P&IDs and other diagrams, drawings, and documents, while overcoming the issues associated with older methods, which required unique function-centric models for each type of field device.

PA-DIM deployment, and FDI

While users can manually create PA-DIM mappings, a better approach is to use Field Device Integration (FDI) packages enabled with PA-DIM.

With FDI, the PA-DIM data is created from the electronic device descriptor (EDD) file associated with the device. OT systems already rely on this EDD file for setup configuration and maintenance of the device, but IT systems do not, they just understand OPC UA.

FDI was jointly developed by leading process industry standards organizations to solve the problem of integrating field devices with the multitude of networks, operating systems, and control systems used in the process industries.

Simplifying data access with PA-DIM

PA-DIM is a significant advancement for bridging the OT/IT gap with its standardized approach to data integration. By leveraging OPC UA and aligning with NAMUR NOA requirements, PA-DIM facilitates simplified and seamless data flow from field devices to enterprise systems, enhancing data accessibility and usability for improved operational efficiency and insight generation.