Fronius Manual


  1. Fix unit to wall: Your myWatt unit comes with a choice of fixings to attach it to the wall next to your Fronius inverter
  2. Power up: Connect the supplied A/C power adapter to the myWatt unit and plug it into a  nearby wall socket
  3. Connect the myWatt to your inverter: 
Last updated on April 2, 2019

Configuration of Fronius Inverters to work with myWatt

myWatt monitors Fronius inverters using the SunSpec Alliance protocol, which require that the inverter be enabled to Modbus-TCP.


  • Fronius inverter installed, running and configured on customers network (ethernet or Wi-Fi)
  • Physical access to the inverter’s control panel
  • A smart device with Wi-Fi networking, preferably a tablet or laptop as the Fronius web interface does not adapt well to the small screen of a mobile phone
  • Fronius inverter front panel in its default “AC Output Power” display
Last updated on April 2, 2019

Putting the inverter into Wi-Fi Access Point mode

    1. Press the back button (the third button from left) to change the display mode
      Fronius Setup start
    2. Press the right arrow (the second button from left) and scroll through to SETUP. Then hit the enter button (the last button on the right)
      Fronius Wifi - Step 1
    3. From the Setup display, scroll down to Wi-Fi Access Point using the down button (second button on the left). Then hit the enter button (the last button on the right)
      Fronius WiFi Setup 3
    4. The display will change to show the Wi-Fi Access Point status. Press the enter button again to again to activate the Wi-Fi Access Point
      Fronius Wifi - Step 5
    5. You should now see a screen similar to the below. Confirm that the Wi-Fi Access Point is now Active and the screen shows the Wi-Fi SS: FRONIUS_240.xxxx (the x represents numbers) and PS: 12345678
      Fronius Setup 12
Last updated on March 28, 2019

Enabling Modbus-TCP via the web interface

With the inverter in Wi-Fi Access Point mode, use your smart device to access the inverter.

  1. On your smart device, go to your Wi-Fi settings and select the Wi-Fi Access Point shown on the inverters front panel e.g. FRONIUS_240.xxxx
  2. Open up your web browser and enter the inverter’s IP address,
  3. The web page will display the Fronius inverter’s output. Click on the Settings link in the right hand panel
  4. Now click on the MODBUS tab in the left hand panel
    • Set the “Data export via Modbus” to “tcp
    • Set the “Modbus port” to 502 (this is the default)
    • The “String control address offset” is not important
    • The “Sunspec Model Type” can be set to either “float” or “int+SF”, it does not need to be changed
    • Make sure “Demo mode” is disabled
    • If the customer is required to have grid export limitation, enable “Inverter control via Modbus” and disable “Restrict the control”
      Fronius Interface Diagram
  5. Once you have completed Step 4, click the big tick to save them. You should see an alert message pop up that confirms the settings were applied successfully. Click the OK button to dismiss the alert.
Last updated on April 2, 2019

Check the rest of the inverter's setup is correct

  • In the web browser, click on the “GENERAL” tab in the left hand panel to show the System Name, Yield and System Time details. Confirm that the displayed date and time are correct and that the time zone is also correct. Make any required changes and click the big tick to save them
  • Click on the “INVERTERS” tab in the left hand panel to show the System Name and the inverter list. Each inverter will have an assigned number (starting at 1). If any inverter has a number other than 1, make a note of it as you may need to know that number when configuring the inverter in myWatt. If any changes are required, click the big tick to save them.

When all changes have been made, return the web page to the standard display by clicking on the “Current general view” at the top of the right hand panel.

Last updated on April 2, 2019

Turn the Inverter's Wi-Fi Access Point Off

The final step is to return the inverter to normal operation by turning the access point off.

  1. With the inverter’s screen showing the Wi-Fi Access Point status, press the Enter button to deactivate the access point. The screen will return to Setup mode, as seen earlier
    Fronius Setup 12
  2. Use the Left or Right arrow buttons to select the “Home” icon, then press the Enter button to return to the normal display.

This completes the setup of Fronius Inverter for myWatt.

Last updated on April 2, 2019

How to change Fronius Wi-Fi Network Settings

  1. Be near your Fronius inverter and have a Wi-Fi enabled device, such as a smart mobile phone, with you
  2. Make sure your Wi-Fi is active on your device
  3. On the small screen on the front of the inverter press the second button from the left and scroll through to SETUPFronius Wifi - Step 1
  4. To select SETUP, press the last button on the right
    Fronius Wifi - Step 2
  5. From the menu display, scroll down to Wi-Fi Access Point using the second button on the left.Fronius WiFi Setup 3
  6. Press the last button to enter
    Fronius Wifi - Step 5
  7. From this screen, press the last button on the right again
    Fronius Setup 7
  8. Now go to your smart device and go into your Wi-Fi Settings. You want to choose your Fronius inverter’s Wi-Fi signal (hint: it usually starts with 240.???? and it will match the number displayed on your inverter screen (as above)
  9. Select it and when prompted, enter the password – 12345678 and click join
  10. Now, on your smart device bring up your web browser, such as Google Chrome, Internet Explorer or Safari
  11. In the address bar, type the following: and click enter. This will take you to the Fronius Inverter’s home page
  12. On the right hand side of the page is an option called Settings. Click on this and once you are on that page, click on the option in the column on the left hand side called Network
  13. At the bottom of this page will be a list of available networks – look for your network, select it and hit Set…
  14. Enter your password and then select Save
  15. Now select Configure Wi-Fi and ensure that Dynamic is selected and click OK
  16. Scroll to the top of the page and save all changes by clicking on the Tick icon. You should receive a notification showing that the settings were saved successfully.
  17. You now need to check that the settings have been updated in your Inverter. So repeat steps 1-6 to Activate your Wi-Fi Access Point and connect your device to the Wi-Fi Access Point
  18. Finally go back your smart device (repeat steps 10 & 11, if necessary) and select System Information from the column on the right hand side
  19. On the System Information page, look for the row called LED Status. If you see 4 green icons, everything should now be working correctly.
Last updated on March 28, 2019
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