How to Test the Connection to Your SMA Inverter

From on January 25, 2016 in Category Technology with 13 Comments

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.


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  • avatar

    Vincent Quintin

    February 28, 2017 at 20:20


    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.



    Reply »
  • avatar


    February 12, 2017 at 13:50

    Thanks for the discussion on testing the connection to a SMA inverter, it was really helpful to me.

    Reply »
  • avatar


    July 12, 2016 at 13:16

    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,


    Reply »
    • avatar

      Lucas Unbehaun

      July 13, 2016 at 07:55

      Hello Willy,

      please contact my services colleagues directly at, they need further information.

      Kind regards, Lucas

      Reply »
  • avatar


    April 26, 2016 at 00:57

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

    Reply »
  • avatar

    J Dawson

    March 31, 2016 at 06:37

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

    Thanks, Janet.

    Reply »
    • avatar

      Julia Stunz

      March 31, 2016 at 08:48

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

      Best regards,

      Reply »
  • avatar

    Max Müller

    March 10, 2016 at 19:16

    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?

    Reply »
    • avatar

      Julia Stunz

      March 11, 2016 at 09:20

      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,

      Reply »
      • avatar

        Max Müller

        March 11, 2016 at 14:14

        Can I use a data logger/gateway of any brand to get this data query? (i.e. Novus FieldLogger)

      • avatar

        Julia Stunz

        March 11, 2016 at 14:37

        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,

  • avatar

    J.G. Tersteeg

    March 5, 2016 at 17:33

    Hoe krijg ik sunny explorer op mijn tablet

    Reply »
    • avatar

      Leonie Blume

      March 7, 2016 at 16:49

      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.


      Reply »

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