Device integrations

Fronius

Sysmo

Enabling Modbus TCP (SunSpec) on Fronius Inverter

1. Access the inverter's local web interface
Connect to your local network and enter the inverter's IP address in your browser. This opens the Fronius web interface.

2. Go to Settings → Modbus
In the left-hand menu, click MODBUS.

3. Enable Modbus TCP data transfer
Under "Gegevensoverdracht via Modbus" (Data transfer via Modbus), select tcp.

4. Set the SunSpec Model Type
Under "Sunspec Model Type," select int + SF (integer + scale factor). This is the standard SunSpec register format most third-party EMS platforms, including ours, expect.

5. Verify the Modbus port
The default Modbus port is 502. Leave this unless your network setup requires a different port.

6. Enable inverter control via Modbus
Make sure the checkbox "Inverterbesturing via Modbus" (Inverter control via Modbus) is checked. This allows the EMS to send control commands (curtailment, setpoints, etc.), not just read data.

7. Confirm and save
Click the checkmark (✓) icon top-right to save the settings.

The Modbus page in the Fronius inverter settings, in Dutch, with data transfer over Modbus set to tcp and the Sunspec model type set to int plus SF.

8. Enable data logging during night hours
Go to FRONIUS SOLAR.WEB in the left menu, and under "Datalogging tijdens de nachturen" (Data logging during night hours), select Ja (Yes). This prevents the inverter from powering down its communication interface overnight, which would otherwise cause the EMS to lose connection during nighttime hours.

9. Save these settings too with the ✓ icon.

The Fronius Solar.web settings page, in Dutch, with datalogging during the night hours set to yes.