Modbus TCP
OpenEMS Modbus-API (grid)
OpenEMS
Overview
The OpenEMS Modbus-API is a software interface built into the OpenEMS Edge energy management platform. Configured as a grid meter component, it exposes the grid connection point's real-time data over Modbus TCP on port 502. This template reads two key channels: instantaneous grid active power at address 315 and cumulative grid energy at address 359. Both are floating-point values polled directly from the OpenEMS _sum component block. Connecting the ModbusCloud Gateway to any OpenEMS Edge installation running the Modbus-API Controller gives installers continuous grid visibility inside the ModbusCloud portal without additional hardware.
Use cases
- Monitor instantaneous grid import and export power to verify self-consumption ratios on PV-coupled sites.
- Track cumulative grid energy over billing periods to cross-check utility meter readings for accuracy.
- Alert on sustained grid import above a threshold to detect unexpected load increases on managed sites.
- Compare grid power trends before and after battery storage commissioning to verify peak-shaving results.
- Report daily and monthly grid exchange figures for energy performance contracts or grid operator submissions.





