sb_bt

Tool to read power production data for SMA Sunnyboy power invertors on a Linux machine.
Copyright 2012, Creagraphy / Ernst de Moor.

SunnyBoy Bluetooth communications. Reads actual values in a reliable way, and adds them to a CSV file.

This software is to be called from a Cron job, e.g. every 5 minutes.
It will add the current values to a .csv file, with the date as part of the filename.

Examples of filesnames that are created:

• test2012-09-05.csv (with option -f test )
• /tmp/pv-2-2012-09-05.csv (with option -f /tmp/pv-2- )

Optionally this program will set the internal clock of the SunnyBoy, either once a day or every 5 minutes.
This is not necessary for this tool, but might be useful to read the graphs lateron with SunnyExplorer.

Tested with a SMA SunnyBoy 2100TL, but expected to work with all SunnyBoy inverters with a piggyback Bluetooth module.

Usage:

See for installation instructions: https://github.com/creagraphy/sb_bt/wiki/How-to-install

I use this software by calling it from Cron, every 5 minutes.
I use a separate script to upload The resulting CSV file to my webserver, that will add the data to a Mysql DB.
This is done by the upload.sh script (see below), which is too specific to add it to this repo.

To see the resulting graphs: https://creagraphy.nl/grafieken (Dutch page)

Add in /etc/crontab:

# Read Sunnyboy values every 5 minute
*/5 * * * * root /etc/cron.watches/sb_bt -t 1 -a 00:80:25:A4:B6:C2 -p xxxx ; /etc/cron.watches/upload.sh

Commandline options:

Usage: sb_bt [OPTION]...
Read information from SunnyBoy inverter via BlueTooth
Optionally set the internal clock (not necessary for us, but for SMA Sunny Explorer)

Mandatory arguments:

• -a ADDRESS : Bluetooth address of the inverter
• -p PASSWORD : User level password of the inverter (default: 0000)

Optional arguments

• -f FILENAME : Output filename lead-in (date and csv extension is added, default: /tmp/pv-2- )
• -t SETTIME : Set the time of the converter, 1: Once a day, 2: every request
• -v : verbose. If off, the application is silent for cron
• -d LEVEL : activate debug, 1: status info, 2: additional hexdumps, 3: additional translations
• -h : this help info

Files in this repository:

• README.md : This readme file
• sb_bt : A pre-compiled unix executable
• sb_bt.c : The source code
• gpl.txt : The GNU license

How to compile:
gcc -lbluetooth -lm -o sb_bt sb_bt.c

Versions:

• 0.9 : Initial version
• 0.9.1 : Updated readme, added GNU license text
• 0.9.2 : readme info fed back to sourcecode
• 0.9.3 : Remove unnecessary "secret inverter code"
• 0.9.4 : Some improvements in the Readme file
• 0.9.5 : Recognise if the SunnyBoy returns a status message instead of data, and retry (better implementation)
• 0.9.6 : Disconnect SunnyBoy to begin with, sometimes there seem to be hanging sessions
• 0.9.7 : Bugsolve, and better implementation for disconnecting the SunnyBoy. Debug code removed.
• 0.9.8 : (Nick Prater) Fix multiplier on PV Ampere result - reported value was previously 10x actual value
• 0.9.9 : Fix versions (description was outdated), and some minor changes in README.md

Limitations:

• A Little-Endian processor is assumed, because data structures are built directly in memory (using structs). Don't worry, most Linux machines are Little Endian, at least the Intel and ARM processors.
• Probably only works with SunnyBoy inverters with a piggyback BlueTooth module, not with the newer ones with built-in BT.

Technical notes:

• I have put a lot of effort in understanding the communications protocol, and detect CRC errors in messages from the Sunnyboy. Therefore the BT communications is very reliable, chances of reading wrong values are very small.

• I have chosen to communicate with small messages, rather than reading lots of data at once. This makes the communications more reliable too.

• This software uses global data, as it has a very specific use.

  • The config structure contains settings from the commandline.
  • The comms structure holds communications settings like addresses, and the send/receive buffers.
  • The results structure contains the results of querying the Sunnyboys, values for Watt etc.

  making these structures global, keeps the software fast and easy to understand. Note however that the functions are NOT re-entrent because of this. So if you want to use these functions in a multithreading program, or if you want to write a program that communicates with more than one SunnyBoy, you will have to modify the code!

Problems

I sometimes experienced that the BT driver was not up and running, especially after a new Linux release. Some useful Linux commands in my case:

• hciconfig restart
• hciconfig hci0 up
• hcitool scan

Special thanks:

Thanks to the following sources for showing the structuring of data:

• Yasdi tool of SMA themselves (Serial version of the protocol)
• Dean Fogarty : https://github.com/angrytongan/dfinvrelay/
• Wim Hofman and Stephen Collier : http://code.google.com/p/sma-bluetooth/

GNU license

This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program. If not, see http://www.gnu.org/licenses/.