SunSpec Device Interface (SunSpec Modbus) Work Group

The Device Interface (SunSpec Modbus) Work Group will work on updates to the SunSpec Modbus specification package. The updates include additions to SunSpec information modeling, new DER information models for IEEE 1547-2018 support, and a device RESTful web service interface using SunSpec information models. Starting June 2022, the work group will turn its focus to addressing common issues and pitfalls associated with implementing SunSpec Modbus in the IEEE 1547-2018 context. 

Group Leaders

Project Leader(s):

David Erhart of STEM

Bob Fox of DER Security Corp

SunSpec Representative:

Kudrat Kaur

Current Work Items (February – April 2023)

In the first sprint of 2023 this Work Group will work on:

  • Review the following specifications and publish updated versions:
    • SunSpec Device Information Model Specification
    • SunSpec DER Information Model Specification
  • Resolve outstanding SunSpec Modbus issues:
    • Function adopt curve timing
  • Complete SunSpec Modbus Device Web Services API Specification DRAFT


    Topics To Be Covered

    The work group scope is to enhance and develop the SunSpec Modbus interface in each of the functional areas it serves.  As we restart this workgroup, we will focus on the following  areas:

    • Updating the new SunSpec information models that support the IEEE 1547 interface for Distributed Energy Resources
    • SunSpec Device Web Service API Specification
    • Energy Storage model update
    • Implementation Guide for Installers and System Integrators
    • SunSpec Modbus client/gateway compliance criteria and testing program
    • Additional profile development



      You must be a Contributing Member of the SunSpec Alliance to participate in this Work Group. Members may enroll through the Member Portal under ‘work groups’.

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      Meeting Time

      This Work Group meets on Thursdays at 8am PT. Meeting coordinates are provided on the standing calendar invite.


      SunSpec Modbus was officially named in the IEEE 1547-2018 standard as an approved standard interface. Due to functional changes in IEEE 1547, additional SunSpec Modbus information models and data points were required. The current work group effort seeks to ratify the changes made to the SunSpec Modbus models and educate the community how to use these models in practice.


      Work Group Teamwork Shared Space (must be registered to access, contact

      Complete the following form to download the SunSpec Modbus Document package:

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