How to connect Fronius hybrid and solar inverters (SYMO, PRIMO, TAURO, VERTO, GALVO, ECO, GEN24, GEN24 Plus) with Reduxi controller
Connect your Fronius solar or hybrid inverter to the Reduxi Controller via Modbus over Ethernet.
Text description of this image
Photo of a grey and black Fronius inverter on a white background, seen from the front left. Red Fronius logo in an oval on the upper housing, a small display with the value 3840 at the left of the lower part, and the print FRONIUS SYMO in red on the dark lower front panel. Cable glands are visible at the bottom.
1 Technical documentation and supported models
1.1 Supported models
The integration of Fronius solar and hybrid inverters with the Reduxi system uses Modbus communication via Ethernet. These models are supported:
- Symo – Fronius product page
- Symo GEN24 – Fronius product page
- Symo GEN24 Plus – Fronius product page
- Primo UL – Fronius product page
- Primo GEN24 – Fronius product page
- Primo GEN24 Plus – Fronius product page
- Tauro – Fronius product page
- Verto – Fronius product page
- Eco – Fronius product page
SnapINverter models are supported as well.
Text description of this image
Photo of a grey and black Fronius inverter on a white background, seen from the front left. Red Fronius logo in an oval on the upper housing, a small display with the value 3840 at the left of the lower part, and the print FRONIUS SYMO in red on the dark lower front panel. Cable glands are visible at the bottom.
Text description of this image
Photo of a white Fronius inverter seen from the front on a white background. Rounded square white housing with a round black fan grille in the upper right, a black rotary DC disconnect switch at the left edge, and a dark grey panel in the lower part with the red Fronius logo and the print SYMO at the lower right corner of the panel. Small connection fittings are visible at the bottom.
1.2 Fronius manuals
Follow the original Fronius documentation. More information about the Fronius inverters is on the Fronius GEN24 Plus page.
- Fronius operating instructions: network connection – Setting up the LAN or WLAN connection
- Fronius operating instructions: Modbus – Modbus settings of the inverter
- Video: Solar.start app – Installation steps in the app
- Video: network configuration – Connect the inverter to your network
2 Required equipment
You need the following:
- Fronius solar or hybrid inverter
- Reduxi Controller
- Network connection (LAN or Wi‑Fi) for the inverter and for the Reduxi Controller
- Smartphone with the Fronius Solar.start app, or a device that connects to the hotspot of the inverter
- Admin password of the inverter (see Point 3, Point 3.4, if you lost it)
- Laptop or tablet with internet access to configure the device in Reduxi
3 Configure the Fronius inverter
The network and Modbus settings connect the Fronius inverter to the Reduxi environment.
3.1 Install the Solar.start application
Install the Fronius Solar.start app from Google Play or the App Store. The app guides you through the installation steps. For more details, watch the Solar.start video.
Text description of this image
Photo of a smartphone held in a hand, showing the Solar.start app Setup screen on a white background (phone status bar shows 15:39). Top: back arrow, title Setup. Text: Choose product. Three red buttons: GEN24 + TAURO with the subtitle Primo, Symo, Tauro; SnapINverter with the subtitle Eco, Galvo, Primo, Symo, S-Hybrid; OTHER with the subtitle Datamanager Box 2.0, IG Plus. At the bottom left a button CANCEL.
Text description of this image
Photo of a smartphone held in a hand, showing the Solar.start app menu on a white screen with red buttons (phone status bar shows 15:39). Top: back arrow with the text back, user icon at the right. Title: PRIMO GEN24 PLUS. Red button NETWORK with a WiFi symbol: Ethernet (169.254.0.180). Red button PRODUCT with a gears icon: Only for trained technicians. Red button SOLAR.WEB with a graph icon: The network connection has to be configured first!
3.2 Configure the network
Use the app or connect directly to the hotspot of the Fronius inverter. For more details, watch the network configuration video and read the Fronius manual.
Text description of this image
Screenshot of a manual page (text on white background) with the heading LAN: and a small icon of an inverter connected by a cable plug to a router. Text: Establishing a connection: 1 Enter the host name. 2 Select the connection type: Automatic or Static. 3 For the Static connection type, enter the IP address, subnet mask, DNS, and gateway. 4 Click the Connect button. Result line with check mark: The connection is established. Closing sentence: After connecting, the status of the connection should be checked (refer to the chapter headed Internet services on page, with a blue link and a page arrow).
Text description of this image
Screenshot of a manual page (text on white background), titled Selecting and connecting to a WLAN network. Text: The networks found are displayed in the list. Clicking on the Refresh button will perform a new search for available WLAN networks. The selection list can be limited further via the Search network input field. Numbered steps: 1 Select network from the list. 2 Select the connection type: Automatic or Static. 3 For the Automatic connection type, enter the WLAN password and host name. 4 For the Static connection type, enter the IP address, subnet mask, DNS, and gateway. 5 Click the Connect button. Result line with check mark: The connection is established. Closing sentence: After connecting, the status of the connection should be checked (refer to the chapter headed Internet services on page, with a blue link and a page arrow).
3.3 Log in with the admin password
On some inverters you need the admin password to change the Modbus settings. Log in with it first.
Text description of this image
Screenshot of a Fronius inverter web interface login page on white background. Heading: Login (blue). Dropdown with the selected user: admin. Password field, empty (placeholder Password). Checkbox: Keep me logged in, not ticked. Button: Login (greyed). Blue link: Forgot password?
3.4 Reset a lost admin password
If you lost the admin password, request a new one in the Solar.web portal:
Text description of this image
Screenshot of a Fronius inverter web login page. Heading: Login (blue). Dropdown: -- Select user --. Password field (empty, placeholder Password). Checkbox: Keep me logged in, not ticked. Button: Login (greyed). Blue link Forgot password? marked with a red rectangle.
Text description of this image
Screenshot of the Fronius inverter web page Forgot password. Text: Choose a user for which you want to reset the password. Dropdown: admin. Text: The pin for resetting the password is, followed by a 6-digit PIN circled with a red ellipse (value not reproduced here). Text: System owners may reset the admin password themselves in Solar.web under Settings-Components. For all other passwords please contact the Fronius TechSupport, there you will receive your recovery key. Fields: Recovery key (empty), Password (empty), Repeat password (empty). Button: Save (greyed). Blue link: Cancel.
Text description of this image
Screenshot of the Fronius Solar.web overview page for the system Reduxi Office Klagenfurt. Top bar: Fronius logo, title Reduxi Office Klagenfurt, Product registration icon, user icon. Menu: OVERVIEW (active, underlined), ANALYSIS, ENERGY BALANCE, REPORTS, SERVICE MESSAGES, SETTINGS (circled with a red ellipse), red button PREMIUM. Tiles: CURRENT POWER: inverter icon in a yellow ring, 0 W, Utilization 0 %; ENERGY BALANCE TODAY: No data available, Last update: N/A; EARNING: Total 0.00 EUR; CO2 SAVINGS TOTAL: 0 kg; REDUXI OFFICE KLAGENFURT: illustration of a house with solar panels and a car; KLAGENFURT: weather tile with 20°C, mostly cloudy, wind 2.6 m/s, and a forecast row Today, Th, Fr, Sa, Su, Mo, Tu, We with temperature bars.
Text description of this image
Screenshot of the Fronius Solar.web page for Reduxi Office Klagenfurt, menu COMPONENTS circled with a red ellipse. Menu: PROFILE, IMAGE, CONTACTS, COMPONENTS, PERMISSIONS, TARIFFS, OPERATION MODE (badge NEW), MORE. Heading New device with button ADD. Heading Data sources, table columns: Data source ID, IP Address, active until, Update, Actions. One row: blue check icon, a black bar covers the Data source ID and IP Address (blacked out), Active, Update: Queued. Please wait... with a version number (small). The Actions column with its three-dot icon is circled with a red ellipse. Greyed buttons below the table: CHANGE, DEACTIVATE.
Text description of this image
Screenshot of the Fronius Solar.web page, menu COMPONENTS selected. Top bar: Fronius logo, Reduxi Office Klagenfurt, Product registration, user icon. Menu: PROFILE, IMAGE, CONTACTS, COMPONENTS (active, underlined), PERMISSIONS, TARIFFS, OPERATION MODE (red badge NEW), MORE. Heading New device with button ADD. Heading Data sources, table columns: Data source ID, IP Address, active until, Update, Actions. One row: blue check icon, 240.1947934, 213.164.15.46 (blue link), Active, Queued. Please wait... version 3.31.1-7. A small pop-up menu with the entry Reset admin password appears at the Actions column, circled with a red ellipse. Greyed buttons: CHANGE, DEACTIVATE.
Text description of this image
Screenshot of the Fronius Solar.web page with a Password recovery dialog open over a greyed background. Background: Fronius logo, title Reduxi Office Klagenfurt, Product registration at the top right; menu entries PROFILE, IMAGE, CO..., MORE with a red badge; heading New device with button ADD; heading Data sources with a table. Table columns: Data source ID, IP Address, active until, Update, Actions. One row: blue check icon, Data source ID 240.1947934, IP Address 213.164.15.46 (blue link), active until: Active, Update: Queued. Please wait... with version 3.31.1-7. Dialog Password recovery (close x at the right): field PIN code with info icon, empty, placeholder text Enter the six-digit code. Red button in the dialog: GENERATE AND COPY.
Text description of this image
Screenshot of the Fronius Solar.web page with a Password recovery dialog open over a greyed background. Background: Fronius logo, title Reduxi Office Klagenfurt, Product registration, user icon; menu entries PROFILE, IMAGE, CO..., MORE with a red badge; heading New device with button ADD; heading Data sources with a table, columns Data source ID, Update, Actions; one row with a blue check icon, Data source ID 240.1947934, blue IP link 213.164.15.46, status Active, Update: Queued. Please wait... with version 3.31.1-7; buttons CHANGE and DEACTIVATE (greyed). Dialog Password recovery (close x at the right): PIN code field with a green outline, a 6-digit value is shown (value not reproduced); Recovery key field with a long text string cut off at the field edge, circled in red (value not reproduced). Yellow notice with check icon: The recovery key has been copied to the clipboard. Now go to inverter web interface login-section and insert the recovery key there. Red button: GENERATE AND COPY.
Text description of this image
Screenshot of the Fronius inverter web page Forgot password. Text: Choose a user for which you want to reset the password. Dropdown: admin. Text: The pin for resetting the password is, followed by a 6-digit PIN in bold (value not reproduced here). Text: System owners may reset the admin password themselves in Solar.web under Settings-Components. For all other passwords please contact the Fronius TechSupport, there you will receive your recovery key. A red rectangle marks the three input fields and the Save button: Recovery key (filled with a long text string, value not reproduced), Password (empty), Repeat password (empty), Save (greyed). Blue link below: Cancel.
3.5 Configure Modbus
The Fronius inverter must support Modbus control. Log in with the new password and open the Fronius web interface or app. Set the Modbus settings as shown below.
GEN24 / Verto / Tauro:
Text description of this image
Screenshot of the Fronius inverter web interface (dark grey header with Fronius logo, white page), section Communication, page Modbus. Left menu: Communication (with red back arrow), Network, Modbus (selected), Cloud control, Solar API, Solar.web, Internet Services. Content: heading Modbus. Modbus 0 (M0) RTU: options Modbus Client (selected), Modbus Server, Disabled. Modbus 1 (M1) RTU: options Modbus Client (selected), Modbus Server, Disabled. Heading: Control secondary inverter via Modbus TCP. Toggle Activate: on. Fields: Modbus Port *: 502; SunSpec Model Type *: float (dropdown); Meter Address *: 200. Toggle Allow Control: on. Toggle Restrict Control: off.
SnapINverter:
Text description of this image
Screenshot of the Fronius SnapINverter web interface, page Settings, section MODBUS. Header: Fronius SnapINverter, icons, mail icon with 1, language en, Fronius logo. Left menu: GENERAL, PASSWORDS, NETWORK, FRONIUS SOLAR.WEB, IO MAPPING, LOAD MANAGEMENT, PUSH SERVICE, MODBUS (selected), INVERTERS, FRONIUS SENSOR CARDS, METER, DNO EDITOR. Form Modbus with confirm (check mark) and cancel (x) buttons. Data export via Modbus: off, tcp (selected), rtu. Modbus port: 502. String control address offset: 101. Sunspec Model Type: float (selected), int + SF. Demo mode: not ticked. Inverter control via Modbus: ticked. Restrict the control: not ticked. Section Controlling priorities: 1. Controlling via Modbus, 2. IO control, 3. Dynamic power reduction; Legend: 1 ... highest priority, 2 ... medium priority, 3 ... lowest priority. Note: a change of control priorities is possible only in the DNO editor with the service password. Right side menu: Current data: Current general view; Services: System information, Network diagnostics, Firmware update, Start assistant; User: service, Logout; Settings.
For more details, see the Fronius manual.
4 Log in to the Reduxi web interface
You can open the Reduxi web interface in two ways:
Text description of this image
Screenshot of three Reduxi mobile app screens side by side, with cyan boxes and number badges 2 to 4. Left screen (dashboard, dark theme): menu icon at top left marked with a box and badge 2; 'reduxi' logo; tabs 'Real time data' (active) and 'Statistics'; price 5.79 € and temperature 3.2 °C; energy flow diagram with a house in the centre (-1.25 kW) and icons with values 69.0 W, 1.3 kW, 1.1 kW (red ring), -165.0 W with 97 % (red ring) and 0.0 W values at the bottom; tabs 'Power' and 'Energy'; bottom navigation: Dashboard, Diagnostics, Device control, Settings. Middle screen (side menu): 'reduxi' logo, 'Number of locations: 1233', heading 'Reduxi device management', entries '+ Add Reduxi location' and 'Reduxi devices' (marked with a box and badge 3), then 'My profile' and 'About app'. Right screen (device page): Back; picture of a black Reduxi controller with two Ethernet ports; status 'Connected'; card 'Update available': 'New update is available for your Reduxi device.' with button 'Download and install update'; card 'Connect to configurator': 'Tunnel connection enables remote access to your Reduxi configurator, without need to be connected to the same local network.' with button 'Activate tunnel connection' (marked with a box and badge 4); card 'Unit details' with field 'Unit ID'.
Text description of this image
Screenshot made of two parts side by side. Left part: Reduxi mobile app screen on a dark background. Top: Back button; picture of a black Reduxi controller with two Ethernet ports and a terminal block; status 'Connected' with a Wi-Fi icon. Card 'Update available': 'New update is available for your Reduxi device.' with button 'Download and install update'. Card 'Connect to configurator' with a key icon: 'Tunnel connection enables remote access to your Reduxi configurator, without need to be connected to the same local network.' and button 'Open configurator', marked with a cyan box and number badge 5. Below: card 'Unit details' with a field 'Unit ID' (value not visible). Right part: Reduxi Configurator opened in a browser, marked with a cyan frame and number badge 6. Header: back arrow, 'Tunnel connection', reload icon. Left sidebar with icons (lightning, chip, lightning bolt, bar chart, gear). Page 'Home' with a green link icon. Green notice: 'New patch available. Click here to apply.' with a close X. Time 09:12:56. Energy flow diagram with a house in the centre (1.700 kW) and icons for grid (0.000 kW), solar (1.700 kW), battery (green, 0.000 kW and 0.800 kW), a device at left (0.900 kW), electric vehicle and a charger or device at bottom. Label 'Energy manager' at the bottom.
http://reduxi.local. You can find the controller's IP address in your router's device list or in the Reduxi app under Reduxi devices.admin · Password: admin (factory default)Text description of this image
Screenshot of the Reduxi Configurator login page in a Chrome browser window. The address bar shows 'Not secure' and 'reduxi.local'; the address bar is marked with a cyan box and an enlarged copy of it (cyan box, text 'Not secure reduxi.local') is shown at the left, connected by a cyan line. Page background: light grey line drawing of a house with solar panels (green), a wall box, an inverter, a car and a charger. Top left: 'reduxi configurator' logo. Login box in the centre with title 'Login', a language selector (English flag, 'English'), a username field and a password field, and a dark 'Login' button.
Text description of this image
Screenshot of the Reduxi Configurator web interface after login, light theme. Top left: 'reduxi configurator' logo. Header bar: 'Home' at left, green 'Connected' status at top right. Left sidebar: expanded section 'Devices' with a list of entries, then collapsed sections 'Manager' and 'Configuration' and 'Settings'. Main area: energy flow diagram. House in the centre with ring, value 24.20 kW. Grid icon at top left, 24.20 kW (red dot on its line). Solar icon at top right, value '-'. Left icon (battery or device), 6.700 kW (green dot on its line). Right icons (battery storage and a device), values '-'. EV charger icon at bottom left, 31.00 kW. A further device icon at bottom right. Label 'Energy manager' below the house.
5 Add the Fronius inverter to Reduxi
Use these steps to add a new Fronius inverter or to edit an existing one. The general procedure is in section 7 "Devices" of the Reduxi Configurator article.
5.1 Basic settings
Log in to the Reduxi Configurator (see Point 4), click + Add device and select the basic parameters:
- Device type: the matching type, for example
Solar power plant,Batteryor hybrid inverter - Type: the specific model, for example
Symo - Name: a name of your choice
Click Next.
5.2 Communication settings
Enter the IP address, the port and the Modbus unit IDs you configured in Point 3. The example below shows the values:
| Parameter | Example value |
|---|---|
| Connection | TCP/IP |
| IP |
192.168.1.123: the IP address of your inverter |
| Port | 502 |
| Modbus unit ID of inverter | 1 |
| Modbus unit ID of energy meter | 200 |
Text description of this image
Screenshot of the Reduxi web page Communication channel and device configuration (light grey form). Fields: Connection *: TCP/IP (dropdown); IP *: 192.168.1.123; Port *: 502; Modbus unit ID of inverter *: 1; Modbus unit ID of energy meter *: 200. Buttons at the bottom: Back (left), Test communication, Next (dark, right).
5.3 Test communication
Click Test communication at the bottom of the wizard. It reads the Fronius inverter once and saves nothing. If the test succeeds, click Done: only Done creates the device.
Text description of this image
Screenshot of the bottom button bar of a Reduxi Configurator page. Left: button 'Back'. Right: button 'Test communication' (marked with a cyan box) and dark button 'Done'.
Text description of this image
Screenshot of the Reduxi Configurator page 'Communication channel and device configuration'. Connection *: TCP/IP (dropdown). IP *: 192.168.50.243, with button 'Scan for IP'. Port *: 502, with button 'Test port'. Modbus unit ID *: 1. Buttons at the bottom: Back (left), Test communication and Done (right). The Done button is marked with a cyan box.
6 Check the readings
6.1 Test with manual setpoints
Test the function with manually defined setpoints. Open Reduxi – Devices – Fronius and select Manual mode. Try different setpoints and watch how the inverter responds.
Text description of this image
Screenshot of the Reduxi Configurator, page Device / Fronius GEN24, tab Last measurements (other tabs: Analyze, Archive); a dropdown at the top right starts with Each (cut off). Left menu: Reduxi Configurator logo (red arrow pointing at it), Devices (red arrow, minus sign), device list: Fronius GEN24 (red arrow), Iskraemeco AM550, Kronoterm KSM, Tesla - current measurement, Tesla Wall Connector Gen 3; Strategies (plus sign); Utility Rate Plan. Tiles: Control type: buttons Auto (dark) and Manual (turquoise, selected, red arrow pointing at it), timestamp 18. 12. 2024 15:43:07. Grid import active power limit, Grid export active power limit, Battery active power setpoint: each with minus button, empty input field, unit kW, plus button. Mode name setpoint: buttons Max. production, Self consumption, Max. consumption, Peak shaving, Setpoint. Cards: Battery: Active power setpoint, kW, 18. 12. 2024 15:43:11; Grid: Import active power limit and Export active power limit, kW, 18. 12. 2024 15:43:11; Other: Communication error ON, Control type MANUAL, Mode name setpoint.
6.2 Automatic control
When everything works, define strategies, connect to the cloud application and use automatic control. See Strategies for Reduxi controller.
✓ Summary
Preparation (Points 1–2): Check the supported models and the Fronius manuals. Prepare the inverter, the network and a laptop or tablet.
Fronius inverter (Point 3): Install Solar.start, configure the network, note the IP address, get the admin password and set up Modbus. Note port and unit ID.
Add to Reduxi (Points 4–5): Log in to the Reduxi web interface, click + Add device, enter IP, port and unit IDs and click Test communication. Click Done.
Go live (Point 6): Test with manual setpoints. Then define strategies and switch to automatic control.
→ Common issues
| Issue | Solution |
|---|---|
| Modbus settings cannot be changed | Log in with the admin password. If you lost it, reset it as described in Point 3, Point 3.4. |
| Test communication fails | Check the IP address of the inverter, the port and the Modbus unit IDs. Compare them with the Modbus settings of the inverter (Point 3, Point 3.5). |
| Open configurator does not open or stays empty | The tunnel is not active yet. Wait about 30 seconds and check that the controller is online. |
Login with admin is rejected |
The password was changed during installation. Ask the installer. The Reduxi account password does not work here. |
reduxi.local does not load |
Your device is not in the same network as the controller. Use the IP address or the tunnel connection. |
| Communication test fails, device shows offline | Check reachability, IP address / port / unit ID, and that the protocol is enabled on the device. |