Using weeWX to record solar PV power generation data from a Power One Aurora inverter and optionally publish this data to PVOutput

The Aurora extension allows weeWX to download, record and report solar PV power generation data from a Power One Aurora inverter. The Aurora extension also allows optional posting of solar PV power generation data to PVOutput using the PVOutput API.

The Aurora extension consists of:

• a weeWX driver for the Power One Aurora inverter,
• a custom weeWX database schema to support the Aurora inverter,
• a RESTful service for posting data to PVOutput, and
• a utility for bulk uploading of solar PV generation data to PVOutput should Internet access be lost for some period of time.

Note: The weeWX driver used in the Aurora extension was developed using the Power One Aurora Inverter Series Communication Protocol Rel 4.7 dated 19 May 2009 and tested on a Power One Aurora Inverter model PVI-6000-OUTD-AU manufactured in November 2010. Whilst there have been changes to the Aurora inverters manufactured since this time, it could reasonably be expected that the Aurora extension weeWX driver will work with other Aurora models covered by the Communication Protocol Rel 4.7.

The Aurora extension requires weeWX v3.7.0 or greater. Use of the Aurora extension to upload data to PVOutput requires a PVOutput account with system ID and API access key.

The Aurora extension requires a functioning serial communications link between the weeWX machine and the inverter. In my case, this was achieved using a Raspberry Pi 1 model B+ running Raspbian Jessie with a USB-RS485 converter interfacing to the inverter's RS-485 interface. This link functioned without the need for installation of any additional software other than the Aurora extension. There is a lot of information on the Internet, in particular the Whirlpool discussion forum, on interfacing to Aurora inverters.

The Aurora extension can be installed manually or automatically using the wee_extension utility. The preferred method of installation is through the use of wee_extension.

Note: Symbolic names are used below to refer to some file location on the weeWX system. These symbolic names allow a common name to be used to refer to a directory that may be different from system to system. The following symbolic names are used below:

• $DOWNLOAD_ROOT. The path to the directory containing the downloaded Aurora extension.
• $HTML_ROOT. The path to the directory where weeWX generated reports are saved. This directory is normally set in the [StdReport] section of weewx.conf. Refer to where to find things in the weeWX User's Guide for further information.
• $BIN_ROOT. The path to the directory where weeWX executables are located. This directory varies depending on weeWX installation method. Refer to where to find things in the weeWX User's Guide for further information.
• $SKIN_ROOT. The path to the directory where weeWX skin folders are located This directory is normally set in the [StdReport] section of weewx.conf. Refer to where to find things in the weeWX User's Guide for further information.

1. Download the latest Aurora extension from the Aurora extension releases page into a directory accessible from the weeWX machine.

   wget -P $DOWNLOAD_ROOT https://github.com/gjr80/weewx-aurora/releases/download/v0.4.0/aurora-0.4.0.tar.gz
   

   where $DOWNLOAD_ROOT is the path to the directory where the Aurora extension is to be downloaded.

2. Stop weeWX:

   sudo /etc/init.d/weewx stop
   

   or

   sudo service weewx stop
   

3. Install the Aurora extension downloaded at step 1 using the wee_extension utility:

   wee_extension --install=$DOWNLOAD_ROOT/aurora-0.4.0.tar.gz
   

   This will result in output similar to the following:

   Request to install '/var/tmp/aurora-0.4.0.tar.gz'
   Extracting from tar archive /var/tmp/aurora-0.4.0.tar.gz
   Saving installer file to /home/weewx/bin/user/installer/Aurora
   Saved configuration dictionary. Backup copy at /home/weewx/weewx.conf.20170215124410
   Finished installing extension '/var/tmp/aurora-0.4.0.tar.gz'
   

4. Edit weewx.conf:

   vi weewx.conf
   

5. Locate the [Aurora] section and change the settings to suit your configuration with particular attention to the correct setting of the port option:

   [Aurora]
       model = Aurora PVI-6000
       port = /dev/ttyUSB0
       address = 2
       max_tries = 3
       loop_interval = 10
       use_inverter_time = False
       driver = user.aurora
       [[FieldMap]]
           string1Voltage = getStr1V
           string1Current = getStr1C
           string1Power = getStr1P
           string2Voltage = getStr2V
           string2Current = getStr2C
           string2Power = getStr2P
           gridVoltage = getGridV
           gridCurrent = getGridC
           gridPower = getGridP
           gridFrequency = getFrequency
           inverterTemp = getInverterT
           boosterTemp = getBoosterT
           bulkVoltage = getBulkV
           isoResistance = getIsoR
           bulkmidVoltage = getBulkMidV
           bulkdcVoltage = getBulkDcV
           leakdcCurrent = getLeakDcC
           leakCurrent = getLeakC
           griddcVoltage = getGridDcV
           gridavgVoltage = getGridAvV
           gridnVoltage = getPeakP
           griddcFrequency = getGridDcFreq
           dayEnergy = getDayEnergy
   

6. If data is to be posted to PVOutput, locate the [StdRESTful] [[PVOutput]] section ensuring enable is set to true and system_id and api_key are set appropriately:

   [StdRESTful]
       [[PVOutput]]
           enable = true
           system_id = replace_me
           api_key = replace_me
   

   Note: enable is set to false by default during the Aurora extension installation.

7. Save weewx.conf.

8. Edit $BIN_ROOT/user/extension.py:

   $ vi extensions.py
   

9. Add the following lines to extensions.py:

   # ============================================================================
   #                  Aurora units definitions and functions
   # ============================================================================
   
   import weewx.units
   
   # create groups for frequency and resistance
   weewx.units.USUnits['group_frequency'] = 'hertz'
   weewx.units.MetricUnits['group_frequency'] = 'hertz'
   weewx.units.MetricWXUnits['group_frequency'] = 'hertz'
   weewx.units.USUnits['group_resistance'] = 'ohm'
   weewx.units.MetricUnits['group_resistance'] = 'ohm'
   weewx.units.MetricWXUnits['group_resistance'] = 'ohm'
   
   # set default formats and labels for frequency and resistance
   weewx.units.default_unit_format_dict['hertz'] = '%.1f'
   weewx.units.default_unit_label_dict['hertz'] = ' ohm'
   weewx.units.default_unit_format_dict['ohm'] = '%.1f'
   weewx.units.default_unit_label_dict['ohm'] = ' ohm'
   
   # define conversion functions for resistance
   weewx.units.conversionDict['ohm'] = {'kohm': lambda x : x / 1000.0,
                                        'Mohm': lambda x : x / 1000000.0}
   weewx.units.conversionDict['kohm'] = {'ohm': lambda x : x * 1000.0,
                                         'Mohm': lambda x : x / 1000.0}
   weewx.units.conversionDict['Mohm'] = {'ohm': lambda x : x * 1000000.0,
                                         'kohm': lambda x : x * 1000.0}
   
   # assign database fields to groups
   weewx.units.obs_group_dict['string1Voltage'] = 'group_volt'
   weewx.units.obs_group_dict['string1Current'] = 'group_amp'
   weewx.units.obs_group_dict['string1Power'] = 'group_power'
   weewx.units.obs_group_dict['string2Voltage'] = 'group_volt'
   weewx.units.obs_group_dict['string2Current'] = 'group_amp'
   weewx.units.obs_group_dict['string2Power'] = 'group_power'
   weewx.units.obs_group_dict['gridVoltage'] = 'group_volt'
   weewx.units.obs_group_dict['gridCurrent'] = 'group_amp'
   weewx.units.obs_group_dict['gridPower'] = 'group_power'
   weewx.units.obs_group_dict['gridFrequency'] = 'group_frequency'
   weewx.units.obs_group_dict['efficiency'] = 'group_percent'
   weewx.units.obs_group_dict['inverterTemp'] = 'group_temperature'
   weewx.units.obs_group_dict['boosterTemp'] = 'group_temperature'
   weewx.units.obs_group_dict['bulkVoltage'] = 'group_volt'
   weewx.units.obs_group_dict['isoResistance'] = 'group_resistance'
   weewx.units.obs_group_dict['in1Power'] = 'group_power'
   weewx.units.obs_group_dict['in2Power'] = 'group_power'
   weewx.units.obs_group_dict['bulkmidVoltage'] = 'group_volt'
   weewx.units.obs_group_dict['bulkdcVoltage'] = 'group_volt'
   weewx.units.obs_group_dict['leakdcCurrent'] = 'group_amp'
   weewx.units.obs_group_dict['leakCurrent'] = 'group_amp'
   weewx.units.obs_group_dict['griddcVoltage'] = 'group_volt'
   weewx.units.obs_group_dict['gridavgVoltage'] = 'group_volt'
   weewx.units.obs_group_dict['gridnVoltage'] = 'group_volt'
   weewx.units.obs_group_dict['griddcFrequency'] = 'group_frequency'
   weewx.units.obs_group_dict['energy'] = 'group_energy'
   

10. Save extensions.py.

11. Start weeWX:

    sudo /etc/init.d/weewx start
    

    or

    sudo service weewx start
    

The weeWX log should be monitored to verify data is being read from the inverter and, if posting to PVOutput is enabled, data is being posted to PVOutput at the end of each archive period. Setting debug = 1 or debug = 2 in weewx.conf will provide additional information in the log. Using debug = 2 will generate significant amounts of log output and should only be used for verification of operation or testing.

1. Download the latest Aurora extension from the Aurora extension releases page into a directory accessible from the weeWX machine.

   wget -P $DOWNLOAD_ROOT https://github.com/gjr80/weewx-aurora/releases/download/v0.4.0/aurora-0.4.0.tar.gz
   

   where $DOWNLOAD_ROOT is the path to the directory where the Aurora extension is to be downloaded.

2. Stop weeWX:

   sudo /etc/init.d/weewx stop
   

   or

   sudo service weewx stop
   

3. To be written....

General support issues may be raised in the Google Groups weewx-user forum. Specific bugs in the Aurora extension code should be the subject of a new issue raised via the Aurora extension Issues Page.

The Aurora extension is licensed under the GNU Public License v3.