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Fronius Inverter Configuration Guide

How to configure Fronius inverters and test the connection.

Updated 2026-06-02Read in Svenska

Fronius inverters can be configured for Modbus TCP in two different ways, depending on your model. This guide covers both standard Fronius inverters with Datalogger and GEN24 models.

Prerequisites​

Access level requirements vary by model:

  • Standard Fronius with Datalogger : Admin credentials

  • GEN24 : Technician account or Customer account with support assistance

  • Network connectivity

  • Web browser

Configuration for Standard Fronius with Datalogger​

Initial Connection​

  1. Connect to inverter's WiFi access point:

    • Locate network name containing Datalogger ID (240.xxxxx or 239)

    • Use default WiFi password: 12345678

    • Access web interface at 192.168.250.181 (or assigned IP)
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Modbus Configuration​

  1. Log in with Admin credentials

  2. Navigate to Modbus settings

  3. Configure the following:

    • Set "Data export via Modbus" to tcp

    • Change "Sunspec Model type" to float

  4. Save configuration

Note that the modbus configuration will affect the type of the inverter when adding the it to the gateway. There are some options: Fronius, Fronius SF and SunSpec Compatible when adding the device. These must correspond to your Modbus settings in your inverter configuration page.
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Control Priority Setup​

  1. Access DNO Editor

  2. Set "Controlling via Modbus" to priority 1

  3. Adjust priority order if needed

  4. Save changes

Configuration for GEN24 Series​

Initial Access Setup​

  1. Connect to inverter WiFi (password: 12345678 )

  2. Navigate to 192.168.250.181

  3. Access System → Support

  4. Enable both:

    • Remote Access

    • Support User

Modbus Configuration (Technician Access)​

  1. Navigate to Communication → Modbus

  2. Enable "Control via Modbus TCP"

  3. Set String Control Address-Offset to 101 in the inverter settings (or 102 for the second inverter), but always use 1 (or 2 ) in the configurator or app.

  4. Set "SunSpec Model Type" to float

  5. Enable Allow Control

Control Priority Setup​

  1. Access Safety and Grid Regulations

  2. Set Modbus Control to highest priority

  3. Save all changes

Important Notes​

  • Password management varies by model type

  • Multiple inverters require individual configuration

  • Document settings for each unit

Troubleshooting​

Access Issues​

For login problems:

  1. Contact support with model and serial numbers for password resets

  2. Verify network settings

  3. Double-check IP addresses

Configuration Problems​

If experiencing issues:

  1. For GEN24 models, consult installer or Fronius support

  2. Verify all settings are saved properly

  3. Check network connectivity
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Testing connectivity (advanced)

After configuring Modbus TCP on your Fronius inverter, it's important to verify that the connection is working properly. You can follow our testing guide to confirm the connection. For Fronius inverters, use the default Modbus port 502. The Unit ID is typically set to 1, but you might need to check your specific configuration if this doesn't work. Remember that both standard and GEN24 models use the same Modbus TCP port and Unit ID conventions.

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