How I Customized my Inverter Monitoring via Modbus

by Ray Mitchell (guest post), , 11 Comments

After using SMA’s Sunny Portal and Sunny Places web sites to monitor some central inverter PV systems I realized that I wanted more detailed information about system performance than these sites provided.


Specifically, I wanted to know how the individual PV strings in a system were performing so I could get a better idea of the effects of orientation, shading, and other issues. As a result I wrote two custom C# Windows applications to collect data and provide a graphical display of the DC power, current, voltage, and energy production of the individual trackers in the Sunny Boy TL series of inverters, although certain other inverter series should also be compatible.

The first application collects data from all inverters in the system via their Modbus TCP servers every 5 minutes and stores it in daily “history” files on the computer. The second application graphically displays data from these files for the selected day. For the most thorough results I run the data collection application 24/7, but in reality running it only during daylight hours would be sufficient. Since the graphical display application is not involved in data collection I only run it when I wish to view previously collected data. Examples of the graphical displays are provided below.

Power/Energy display for the three strings in a dual SB6000TL-US-22 system. Note the approximate 13% power/energy loss in the inverter2 (1) string due to all-morning chimney shading:




Composite Power/Energy display for the three strings in a dual SB6000TL-US-22 system:



Voltage display for the three strings in a dual SB6000TL-US-22 system:



Current display for the three strings in a dual SB6000TL-US-22 system:



Interested in my application?

If anyone is interested in using my applications I have no problem in sharing them free just for the fame and glory it will bring me 😉 Please write an email to and I will get back to you.

I’m always interested in enhancing and improving what I’ve done. So in case anyone has any requests for different inverter information monitoring, please let me know. I’m looking forward to your feedback and questions in the comment section.


You will find more information on SMA Developer.


  1. Brian Grad says:

    Hello Ray, my wife and I purchased a PV rooftop system for our home in April 2015 and within a couple months our PUD had revised the Interconnection Rules to include language regarding “smart inverter” technology. It creates a provision which may require us to update our inverter if and when a standard emerges to facilitate their ability to manage our co-generation. IEEE 2030 seems to be the emerging standard. Europe uses EEG 2012. I see that SMA produced a Power Control Module for the European market. We have two SMA SB-6000TL-US-22 Inverters. Will the Power Control Module interface with our equipment or is there a product which will expand or upgrade the 6000TL? Will we have to replace our new Inverters in the near future? Any information and assistance in understanding this issue would be greatly appreciated. Thank You, Brian Grad

  2. peter brouwer says:

    Hello Ray,

    Interesting options open up with modbus interface now being available.
    Problem with SMA’s monitoring architecture is that it seems patchy, not everything works with all devices.
    Example for instance is MAC OSX users do not have an option to set parameters in SMA devices like you can do with explorer or webbox. Now that the support foe webbed is gone, mac OS X users are left a bit in limbo. The only way to use explorer is to install a windows version in virtualbox ( free software from Oracle), and use a usb bt adapter.
    I digress, with the new monitoring via modes, it would be nice if the homemanager box could act as mobus proxy/gateway for all installed SMA devices. That way devices with BT communication (no speedwire ) could be monitored too.

    BTW I am interested in a pointer to the software, would like to port it to a raspberrypi/linux version. Already run something on that for monitoring my gas boiler. Using red tool for the database and creating graphs, nice lightweight database software,


    • Nigel Rogers says:

      Hi Peter,

      I think I should be able to assist you. I have sent a Facebook message to someone of your name living in Edinburgh.

      I am only up the road so I am sure we can sort something fairly quickly.


      • Kevin Murray says:


        in your reply to Peter, were you indicating that the Sunny Home Manager could be used as a Modbus proxy to access older Bluetooth inverters?



      • Nigel Rogers says:

        Hi Kevin,
        No – I have seen that line of reasoning elsewhere but to the best of my limited knowledge that is not an option. Having said that I dare say someone will correct me!!
        What I was offering was help in setting up a raspberry pi to interrogate an inverter using the modbus protocol.

        This is something I have recently achieved myself and found it very useful.


  3. Nigel Rogers says:

    Hi Ray,
    Thanks for your article. I was beginning to lose hope that I could even get a conversation about the modbus interface 🙁

    I have a sunny island and a sunny boy. And my biggest frustration was that I couldn’t operate the SI 8.0 remotely as if I was at the control panel. Fortunately I discovered the modbus interface and that has largely changed.

    Thanks to raspberry pi and an rudimentary understanding of python I can now monitor the state of charge (SOC) of my battery bank and top it up at night with grid power (cheapest grid rate) and maintain a minimum SOC during the day – if the forecast or demand was not as expected. What I would like to do is recharge the batteries at a set rate irrespective of consumption, that way I can put on the dishwasher, tumble dryer and washing machine overnight and still be guaranteed that my batteries would be full in the morning. The problem I am having is to determine the correct modbus address that will return the real time consumption ? Any ideas?

    I have tried the obvious choices but don’t get the expected values returned. So I am beginning to doubt the coding or the limited documentation

    Kindest regards

    P.S The other good thing about monitoring the SI is that I can now control the battery room fan and raise alerts without relying on the limited number of internal multifunction relays.

    • Nigel Rogers says:

      Hi Ray,

      Sorry for my earlier posting. I just realised you probably don’t have access to a Sunny Island. In which case my questions would be somewhat unrealistic to answer – my bad.

      As you have kindly stuck your head above the parapet, you may well get loads of questions fired at you like mine. Please keep my details on file and if you think I might be able to assist others then feel free to refer them. I suspect we might generate sufficient traffic for our own forum!

      Kindest regards.


      • Julia Stunz says:

        Hi Nigel,
        Thanks for your comment. Do you have a SMA Energy Meter, to meter the energy consumption?

        Kind regards,

    • Georgina says:

      Hi Nigel,

      I also have a Sunny Island and have been struggling to find the real time consumption – did you manage to get anywhere with this?

      Kind Regards,

  4. Nigel Rogers says:

    Hi Julia.

    The short answer is yes and without it i wouldn’t get those lovely graphs in sunnyportal.

    If I could get access to that data I would be able to drill down on mains consumption. Which should be interesting as I use each phase (l1,l2 and l3) for different purposes as I only have one phase to the house.

    I have requested via the developer team that the data should be in in modbus format too. As there appears to be a demand from owners to get access.

    However if you are referring to my question to Ray regarding consumption I was in fact referring to energy consumed from the battery bank. Which equates to domestic load..

    Kindest regards

  5. Wernich says:

    Hi Nigel,

    Have you been able to communicate with the Sunny Island? We are also experiencing problems to write to the Sunny Island registers using modbus.

    Kind Regards



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