How to Test the Connection to Your SMA Inverter

You have created your own application for querying SMA inverters via SMA Modbus or SunSpec Modbus. Unfortunately, something does not seem to be working properly and the inverter is not responding as expected.

A Modbus simulator enables you to test the connection to your SMA inverter. Using this tool, you can query the value of a register from your SMA inverter—and if you receive a response, this means that you can rule out the IT environment, for example, as a potential source of the problem.


You can obtain the freeware from the following website:

Modbus Master Simulator

Important: The simulator is not SMA software and we cannot perform any service activities for it.


SMA requirements:
  • Inverter with Speedwire (Ethernet) interface
  • Inverter with Modbus interface


Quick Reference Guide:

1. Set the network address

First, you have to find your inverter’s network IP address. This is the same address where you access the inverter in a web browser or in Sunny Explorer.



Open the tool and choose Connection/Settings or click the icon in the toolbar.


Enter the IP address of the inverter that you want to query.



2. Connect to the inverter

Once you have entered the IP address, connect to the inverter by clicking “Connect.”



3. Create a new file

Once the connection is active, create a new query window.



4. Enter the parameters

Now enter the following parameters:

  1. “Device ID”: 3 (for querying via … 3 – SMA Modbus, 126- SunSpec Modbus)
  2. “Address” (register to be queried; here 30051)
  3. Select “Holding registers” (read and write)

Simulator with SMA documentation

Simulator with SMA documentation


Once you have queried the value of the register, you will receive a response like the one shown above in the sample screenshot.

Register: 30051 (query of device class)

Response: 8001 (output value = Solar inverters)


I hope that this quick reference guide is helpful for you.


How to Test the Connection to Your SMA Inverter
5 (100%) 1 vote

    • Leonie Blume
      Leonie Blume says:

      We regret to tell you that Sunny Explorer is designed for Microsoft Windows OS only. The software won´t be able to run on a tablet device.


  1. Max Müller says:

    I have a STP-12000TL-20 and I am trying to communicate with a 485 Interface Data Module Type B, and this method is not working for me.
    There´s something I am doing wrong?
    If so, where can I find instructions to get data through RS485 to my SCADA system?

    • Julia Stunz says:

      Hello Max,
      We regret to tell you that it isn`t possible to have access to the inverter from type STP-12000TL-20 without a data logger/gateway,
      such as the SMA Sunny Webbox or the SMA Cluster Controller. Therefore, data query through RS485 only through your SCADA system won´t work.

      Kind regards,

      • Julia Stunz says:

        Hi Max,
        We would like to suggest that you contact directly the manufacturer of your choice.
        Please kindly understand that we have not tested all available gateway units.
        Therefore, we can not guarantee the functionality of the data logger you have mentioned in your previous message.

        To learn more about the Modbus protocol interface, please follow the link.

        Kind regards,

  2. J Dawson says:

    Sunny portal iOS app crashes when I try to open it. I tried reinstalling, but that didn’t help. Any ideas?

    Thanks, Janet.

    • Julia Stunz says:

      Hi Janet,
      Could you please tell us, which version of the Sunny Portal App do you use?

      Best regards,

  3. Max says:

    Hi, I have an STP-12000TL-20. Does it have a SMA Modbus / SunSpec ModBus Data Interface? Is it different from STP-12000TL-US?

  4. Willy says:

    I’m trying to write to the registers of the Sunspec Profile (unit id 126) of my Sunny Island 3.0M-11 (with SpeedWirte module). In particular I’m writing a ‘1’ to register 40375 to which I’m supposed to have read/write access. This should change the mode of the battery management system to ‘Battery discharge’. I’m getting no Modbus-exception when I do a ‘Write Multiple Registers’ (Modbus function 16)- but reading that register again shows me no change- it still holds a ‘0’.

    Do I have to login as some super user first, to be able to write to registers of the SunSpec profile?
    Is there any other possibility to manually discharge the battery over Modbus TCP?

    Best regards,


  5. Vincent Quintin says:


    Should it work with this model?

    SB 5000TL-21 536
    Firmware: 02.81.01.R
    Communication version:

    I have just tested with the simulator with the parameters given in this article and I get 65565 as value for all addresses (without any error read or write).

    Via Sunny Explorer, modbus is activated (TCP/502+UDP/502) and Unit Id is well set on 3.

    Thanks in advance for your answer.



  6. Rajko says:

    Hello, I have the STP 1000TL10 inverter, with software 02.55.00.N and Speedwire/webconnect module. I am trying to read Modbus TCP data, but all I got is data showing 4294967295 results. I doubt that the software version is correct because I read that it must be, at least, version 2.65.02.R. Where can I find the upgrading firmware software? I took a look on SMA webpage, but unfortunatly I did not find the correct one for my inverter type.

    Best regards!


    • Rhea Terlinden
      Rhea Terlinden says:

      Dear Rajko,

      Since the inverter has been discontinued already, the firmware updates are available at in the download section “Archive”.
      Please read the update instructions carefully in order to install the update.

      Kind regards


  7. Jeroen says:

    I have the Sunny Boy 3600 Smart Energy and I’m using Modbus to charge/discharge the battery.
    When I send the 6 commands for grid management per second, the battery charges/discharges but after 10 seconds the Sunny Home Manager takes over for a short time.

    I changed the time between the commands but that doesn’t help.

    Can someone help me please?

    Best Regards,


    • Carolyn Schlosser
      Carolyn Schlosser says:

      Hello Jeroen,

      Please contact you installer. He knows your system and the local conditions the best. In case he is not able to help you, feel free to sign in on our Service-Line.

      Sunny regards,

      • Sheshbahadur says:

        Hello Carolyn ,
        We have installed SMA Sunny Tripower Solar Inverter Model No : STP25000TL-30 , Serial No : 1901252689.
        Connected the Internet cable on Lan Port A , But Inverter is unable to get IP address and other Information due to this we are unable to view online data, If we remove the cable and connect to Laptop we are able to browse the internet , kindly let us if any setting or configuration need s to activated or deactivated. Router is on DHCP . Could you guide us what is the problem

  8. Jeff Unabia says:

    We installed an Inverter Manager and a Janitza meter for the zero export function.
    We already configured the details on the “Limited Export” tab of the LCS tool.
    Is there other configurations that we need to do to assure that there will be a zero export?
    We got advised that we need to access Sunspec Modbus and set register 19026 to zero,


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