> For the complete documentation index, see [llms.txt](https://docs.voltmasters.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.voltmasters.io/device-integrations/pv-inverters/fronius.md).

# Fronius

#### 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.

<figure><img src="/files/nAhUf1Frrydl9NDYkIH1" alt=""><figcaption></figcaption></figure>

**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.

<figure><img src="/files/2KZZyDTVH4JQwRRC486i" alt=""><figcaption></figcaption></figure>


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