Hart Communication Protocol


The process automation industry uses several standards-based automation protocols, including HART, FOUNDATION Fieldbus and PROFIBUS PA to represent information made available by field instrumentation. Since each automation protocol represents field device information differently, integration of information from process automation OT (operational technology) to higher level IT systems is difficult. And with an extremely large installed base of instrumentation, it is hard to imagine how the OT/IT chasm can be bridged without a common “information model” to represent information generated by the different protocols. 

To ensure interoperability and seamless access to device information, it is necessary to standardize on the form and basic contents of the information models for certain device classes independent of a specific communication protocol, thus enabling seamless instrumentation information flow throughout the enterprise.

In short, PA-DIM is a common language for describing device data regardless of protocol, type of device or manufacturer.

In 2017 FieldComm Group and the OPC Foundation formed a joint working group to specify a Process Automation Device Information Model (PA-DIM®), using the OPC UA information modelling specification, that would be used to bridge this gap.  The scope of the working group is to:

  • Prepare and propose enhancements to the OPC UA Unified Architecture for Devices (DI) companion specification.
  • Ensure compatibility between FDI Technology specifications and the OPC UA 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@ss.
  • Enhance the OPC UA Information Model for FDI based on requirements from e.g. NAMUR Open Architecture, Industrie 4.0 or IIoT initiatives.

Understanding Semantic Identification

One of the principle benefits of PA-DIM is the ability to “map” protocol specific parameters to globally standardized terms for these parameters.

Registered Products

FieldComm Group’s Product Registry provides a current list of Registered FDI, FOUNDATION Fieldbus and HART products from a multitude of manufacturers and categories. Products that carry the registration mark(s) have been tested in our lab to ensure conformance to the standards for interoperability and functionality regardless of manufacturer.


All PA-DIM development requires the use of the PA-DIM Specifications. These Specifications are available now.

Development Tools

FieldComm Group provides test and registration services for developers of PA-DIM technology based products. FDI Development Tools provide the software needed to build PA-DIM enabled products.


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