question

Updated with latest results on 17-Apr-2020

Situation

At home, I have three roofs (east, south and west) with 9.9 kWp PV feeding into a Fronius Symo 8.2-3-M. The setup has Fronius Smart Meter 63A-3.
In a few days I am adding a Multiplus-II 48/5000/70-50 and 2x Pylontech US2000 (4.4 kWh net) LiFePO battery.

Problem

I am running Venus OS on a Raspberry 3B+. It nicely shows the power fed in by the Symo, with all details.

Venus is not showing any data from the Fronius Smart Meter.

Vision

I would like to have the data from the Fronius Smart Meter available on the Venus.

My idea is that I need a driver for Venus OS, which gets the data from the Smart Meter via the http API that Fronius provides and passes that information onto dbus - where hopefully Venus treats the data as if it came from a meter that it knows.

Steps Forward

I searched for a solution to my problem on the internet.I thought that I can not be the first to have this issue. But I found no direct solution.

There are several projects that might be a good start for getting to a solution:

• dbusdummyservice.py from velib_python
  A simple service on the dbus.
• dbus-cgwacs
  Reads energy measuremens from Carlo Gavazzi Wired AC Sensors (hence cgwacs), and puts it on the D-Bus.

Both projects look like a good start for programming my own solution.

Python script emulating the Victron Grid meter

Using dbusdummyservice.py from velib_python as a basis, I wrote this script:

#!/usr/bin/env python
 
"""
Used https://github.com/victronenergy/velib_python/blob/master/dbusdummyservice.py as basis for this service.
Reading information from the Fronius Smart Meter via http REST API and puts the info on dbus.
"""
import gobject
import platform
#import argparse
import logging
import sys
import os
import requests # for http GET
 
# our own packages
sys.path.insert(1, os.path.join(os.path.dirname(__file__), '../ext/velib_python'))
from vedbus import VeDbusService
 
class DbusDummyService:
  def __init__(self, servicename, deviceinstance, paths, productname='Fronius Smart Meter', connection='Fronius SM service'):
    self._dbusservice = VeDbusService(servicename)
    self._paths = paths
 
    logging.debug("%s /DeviceInstance = %d" % (servicename, deviceinstance))
 
    # Create the management objects, as specified in the ccgx dbus-api document
    self._dbusservice.add_path('/Mgmt/ProcessName', __file__)
    self._dbusservice.add_path('/Mgmt/ProcessVersion', 'Unkown version, and running on Python ' + platform.python_version())
    self._dbusservice.add_path('/Mgmt/Connection', connection)
 
    # Create the mandatory objects
    self._dbusservice.add_path('/DeviceInstance', deviceinstance)
    self._dbusservice.add_path('/ProductId', 16) # value used in ac_sensor_bridge.cpp of dbus-cgwacs
    self._dbusservice.add_path('/ProductName', productname)
    self._dbusservice.add_path('/FirmwareVersion', 0.1)
    self._dbusservice.add_path('/HardwareVersion', 0)
    self._dbusservice.add_path('/Connected', 1)
 
    for path, settings in self._paths.iteritems():
      self._dbusservice.add_path(
        path, settings['initial'], writeable=True, onchangecallback=self._handlechangedvalue)
 
    gobject.timeout_add(200, self._update) # pause 200ms before the next request
 
  def _update(self):
    URL = "http://10.194.65.143/solar_api/v1/GetMeterRealtimeData.cgi?Scope=Device&DeviceId=0&DataCollection=MeterRealtimeData"
    meter_r = requests.get(url = URL)
    meter_data = meter_r.json() 
    MeterConsumption = meter_data['Body']['Data']['PowerReal_P_Sum']
    self._dbusservice['/Ac/Power'] = MeterConsumption # positive: consumption, negative: feed into grid
    self._dbusservice['/Ac/L1/Voltage'] = meter_data['Body']['Data']['Voltage_AC_Phase_1']
    self._dbusservice['/Ac/L2/Voltage'] = meter_data['Body']['Data']['Voltage_AC_Phase_2']
    self._dbusservice['/Ac/L3/Voltage'] = meter_data['Body']['Data']['Voltage_AC_Phase_3']
    self._dbusservice['/Ac/L1/Current'] = meter_data['Body']['Data']['Current_AC_Phase_1']
    self._dbusservice['/Ac/L2/Current'] = meter_data['Body']['Data']['Current_AC_Phase_2']
    self._dbusservice['/Ac/L3/Current'] = meter_data['Body']['Data']['Current_AC_Phase_3']
    self._dbusservice['/Ac/L1/Power'] = meter_data['Body']['Data']['PowerReal_P_Phase_1']
    self._dbusservice['/Ac/L2/Power'] = meter_data['Body']['Data']['PowerReal_P_Phase_2']
    self._dbusservice['/Ac/L3/Power'] = meter_data['Body']['Data']['PowerReal_P_Phase_3']
    self._dbusservice['/Ac/Energy/Forward'] = meter_data['Body']['Data']['EnergyReal_WAC_Sum_Consumed']
    self._dbusservice['/Ac/Energy/Reverse'] = meter_data['Body']['Data']['EnergyReal_WAC_Sum_Produced']
    logging.info("House Consumption: %s" % (MeterConsumption))
    return True
 
  def _handlechangedvalue(self, path, value):
    logging.debug("someone else updated %s to %s" % (path, value))
    return True # accept the change
 
def main():
  logging.basicConfig(level=logging.INFO)
 
  from dbus.mainloop.glib import DBusGMainLoop
  # Have a mainloop, so we can send/receive asynchronous calls to and from dbus
  DBusGMainLoop(set_as_default=True)
 
  pvac_output = DbusDummyService(
    servicename='com.victronenergy.grid',
    deviceinstance=0,
    paths={
      '/Ac/Power': {'initial': 0},
      '/Ac/L1/Voltage': {'initial': 0},
      '/Ac/L2/Voltage': {'initial': 0},
      '/Ac/L3/Voltage': {'initial': 0},
      '/Ac/L1/Current': {'initial': 0},
      '/Ac/L2/Current': {'initial': 0},
      '/Ac/L3/Current': {'initial': 0},
      '/Ac/L1/Power': {'initial': 0},
      '/Ac/L2/Power': {'initial': 0},
      '/Ac/L3/Power': {'initial': 0},
      '/Ac/Energy/Forward': {'initial': 0}, # energy bought from the grid
      '/Ac/Energy/Reverse': {'initial': 0}, # energy sold to the grid
    })
 
  logging.info('Connected to dbus, and switching over to gobject.MainLoop() (= event based)')
  mainloop = gobject.MainLoop()
  mainloop.run()
 
if __name__ == "__main__":
  main()

The script registers itself on dbus as "com.victronenergy.grid" and publishes values as defined on Venus wiki - dbus - Grid meter .

Before I run the script, I have the following situation on the remote console, feeding 3.9 kW to the grid:

When I run the script, I see the following situation on the remote console, as if the AC Loads would consume 3.9 kW:

So, clearly, my script does something. But not what I wanted.

As the next step, I added three paths to the script: "/Ac/L1/Power", "/Ac/L2/Power" and "/Ac/L3/Power" and then it worked. So, the "/Ac/Power" was not enough for Venus to accept the data as valid- it needed power for all three phases separately.

Now the remote console shows:

Final thoughts

So, it is possible to use a Fronius Smart Meter and make Venus see it correctly.

I think this could be useful for other users as well, therefore it now can be found together with some documentation on GitHub: venus.dbus-fronius-smartmeter