The Process Automation Device Information Model Standard (PA-DIM) is a specification that defines protocol agnostic communication of common process automation instrument parameters, including semantic IDs as defined by IEC 61987, using OPC UA information modeling techniques. Eliminating protocol dependencies simplifies the integration of IT and OT systems, while enabling a semantic device information approach for unambiguous machine-to-machine (M2M) communication. Fieldbus-specific implementations are converted into the address space of the PA-DIM Information Model. Seamless communication is achieved through data-mapping of fieldbus-specific instrument parameters using the address space defined in PA-DIM specification.
PA-DIM fulfills NoA-Use-Cases. Products using PA-DIM can easily support the NAMUR Open Architecture (NOA) use cases including automated as built, unique identification, device dimensioning, multivariable possibility check, read multivariable process values, device life cycle backup, health monitoring, and diagnosis.
The PA-DIM Owners Alliance includes standards development and end user organizations that share a common interest in collaboratively developing specifications and technology to accelerate the digital transformation of the process automation industry. Each participating organization in the Alliance is a co-owner of the PA-DIM specification which is managed by the FieldComm Group hosted PA-DIM Working Group. The PA-DIM activities started in 2017 as a Joint Working Group of the OPC Foundation (OPC) and the FieldComm Group, Inc. (FCG). In 2022 the ownership has been extended to NAMUR, ODVA, PNO, VDMA, WCI-ASCI, and ZVEI.
Current Alliance organizations are:
- The scope of the Joint Working Group is to prepare and propose enhancements to the OPCUA Unified Architecture for Devices (DI) companion specification.
- Ensure compatibility between FDI Technology specifications and the OPCUA Unified Architecture for Devices (DI) companion specification
- Specify and maintain OPC UA Information Models for Process Automation Devices initially based on NAMUR Core Parameters according to NE 131 including assignment of semantic identifiers according the IEC Common Data dictionary and/or eCl(at)ss
- Enhance the OPC UA Information Model for FDI based on requirements from e.g. NAMUR Open Architecture, Industrie 4.0 or IIoT initiatives
FDI Technology and the OPC UA Information Model for Process Automation Device shall enable client applications to access device information and specifically Process Automation Device Information in a standardized vendor independent way and independent of specific fieldbus protocols. The access can happen through an OPC UA Server directly integrated in a Process Automation Device, or through an OPCUA Server aggregating multiple Object Dictionaries of multiple Process Automation Devices, or through the Object Dictionary of an FDI OPC UA Server representing multiple Process Automation Devices. By this device information can be provided to the enterprise level, e.g. for diagnostics, configuration, condition monitoring, visualization, maintenance etc.
The use cases define the content of this Device Information Model and can be broken into Telemetric and Asset Management categories. Telemetric use cases publish dynamic data e.g. to a cloud application for remote monitoring. Asset Management use cases require client server interaction with the information model typically for on-premises applications.
NAMUR Open Architecture (NE175) defines uses cases with parameters, names and semantic ids, which are an important input for the definition of the PA-DIM. Additional details about these use cases can be found in the NAMUR descriptions found on their web site referenced in Section two.