Install you Raspberry Pi with NOOBS:

NOOBS Download from Raspberrypi.org

Install and configure SBFSpot for the logging of your SMA inverter

SBFSpot installation on the Rpi

Make sure that csv logging is enabled, since my python script uses these files.

Log in using ssh on the Pi

Install the wiringpi2 library on the raspberry:

sudo apt-get update
sudo apt-get install python-dev python-pip
sudo pip install wiringpi2

Now the actual script that filters the power data from the SMA logging:

mkdir /home/pi/scripts
nano /home/pi/scripts/show_actual.py

Adjust the values in #defines to match your preferences

#!/usr/bin/python

import time
import datetime
import wiringpi2 as wiringpi
import os.path

#defines:
system_name="Your_Pv_System"            # System namen in SBFspot
sbfspot_log_location="/home/pi/smadata/"    # logging of SBFspot
meter_zero_offset=0                # normal range: 0-1024, offset range = 100-1024
meter_max_offset=0                # normal range: 0-1024, offser range = 0-824
max_kwh_day=30                    # max kwh generated in 1 day
max_power=6000                    # max inverter AC power feed
debug_mode=1                    # print information while running

#initialise PWM
wiringpi.wiringPiSetupGpio()  
wiringpi.pinMode(18,2)                # pwm only works on GPIO port 18  
wiringpi.pwmWrite(18, 0)            # duty cycle between 0 and 1024. 0 = off, 1024 = fully on  

previous_value = 0
daynight="none"

while 1 == 1:
    prev_daynight=daynight
    #Read & parse SBFspot generated datafile
    fulldate= str(datetime.datetime.now().year) + str(datetime.datetime.now().month).zfill(2) + str(datetime.datetime.now().day).zfill(2)
    datafile=sbfspot_log_location + str(datetime.datetime.now().year) + "/" + system_name + "-Spot-" + fulldate + ".csv"
    if os.path.isfile(datafile) == True:
        file = open(datafile)
        for line in file:
            pass    # Get last line in log
        file.close()
        actual_data = line.split(',')
        # Appoint values from csv columns
        actual_power = actual_data[20]
        total_kwh_today = actual_data[22]
        gridrelay_status = actual_data[29]    #Daytime, gridrelay_status = "Closed"
        if gridrelay_status == "Closed":     # Day mode: show actual power
            daynight = "day"
            actual_value = float(actual_power)
            maxvalue=max_power
        else:
            daynight = "night"        # Night mode: show total energy generated today
            actual_value = float(total_kwh_today)
            maxvalue=max_kwh_day
    
        if actual_value > maxvalue: actual_value = maxvalue
    
        if (previous_value != actual_value) or (prev_daynight != daynight):
            if debug_mode==1: 
                print "gridrelay: " + gridrelay_status
                print "Actual Power:\t\t" + str(actual_power)
                print "Total kWh today:\t" + str(total_kwh_today)
    
            for i in range (1,21):
                newvalue = previous_value+((actual_value-previous_value)/20)*i
                value_out = int(meter_zero_offset+(newvalue/maxvalue)*(1024-meter_zero_offset-meter_max_offset))
                wiringpi.pwmWrite(18, value_out )
                if debug_mode==1: print ("New val: %8.3f\tMax val: %d\tPct: %6.2f\t0-1024: %4d" % (newvalue, maxvalue, (newvalue/maxvalue)*100, value_out))
                time.sleep( 0.25 )
            previous_value = actual_value
        else: time.sleep( 1 )
    else: time.sleep ( 5 )

Test the script by executing the following command:

sudo python /home/pi/scripts/show_actual.py

pi@raspberrypi ~ $ sudo python /home/pi/scripts/show_actual.py
gridrelay: Open
Actual Power:        0.000
Total kWh today:    5.987
New val:    0.299    Max val: 30    Pct:   1.00    0-1024:   10
New val:    0.599    Max val: 30    Pct:   2.00    0-1024:   20
New val:    0.898    Max val: 30    Pct:   2.99    0-1024:   30
New val:    1.197    Max val: 30    Pct:   3.99    0-1024:   40
New val:    1.497    Max val: 30    Pct:   4.99    0-1024:   51
New val:    1.796    Max val: 30    Pct:   5.99    0-1024:   61
New val:    2.095    Max val: 30    Pct:   6.98    0-1024:   71
New val:    2.395    Max val: 30    Pct:   7.98    0-1024:   81
New val:    2.694    Max val: 30    Pct:   8.98    0-1024:   91
New val:    2.994    Max val: 30    Pct:   9.98    0-1024:  102
New val:    3.293    Max val: 30    Pct:  10.98    0-1024:  112
New val:    3.592    Max val: 30    Pct:  11.97    0-1024:  122
New val:    3.892    Max val: 30    Pct:  12.97    0-1024:  132
New val:    4.191    Max val: 30    Pct:  13.97    0-1024:  143
New val:    4.490    Max val: 30    Pct:  14.97    0-1024:  153
New val:    4.790    Max val: 30    Pct:  15.97    0-1024:  163
New val:    5.089    Max val: 30    Pct:  16.96    0-1024:  173
New val:    5.388    Max val: 30    Pct:  17.96    0-1024:  183
New val:    5.688    Max val: 30    Pct:  18.96    0-1024:  194
New val:    5.987    Max val: 30    Pct:  19.96    0-1024:  204

Crtl+c to quit....

Now to make the datalogger and meter controller run automatically at boot:

sudo nano /etc/rc.local

/home/pi/scripts/SBFspot.sh > /dev/null 2>&1 &
python /home/pi/scripts/show_actual.py > /dev/null 2>&1 &

exit 0

Create an additional script to run SBFSpot every 5 seconds, except in the night time...

Tweak the location to the SBFspot binary if neccessary

nano /home/pi/scripts/SBFspot.sh

#!/bin/bash

sbfspot_bin_path="/home/pi/smaspot/SBFspot/bin/Release"

while true
do
cd $sbfspot_bin_path
if timeout 10s ./SBFspot -v | grep -q "it's dark"; then 
# It is dark... using 5 minute delays and skipping file writes
sleep 300
else
# Update log every 5 seconds
sleep 5
fi
done

(Optional): If you are using a wifi dongle, it's wise to monitor the connection (no auto reconnect on NOOBS)

sudo nano /home/pi/scripts/keep_wifi_alive.sh

#!/bin/bash

   if ifconfig wlan0 | grep -q "inet addr:"; then
    echo
   else
    date=$(date)
        echo "Wifi down @ " $date ", Trying to reconnect" >> /tmp/wifi_status 
        ifup --force wlan0
    if ifconfig wlan0 | grep -q "inet addr:"; then
        echo "Reconnection succesful!"  >> /tmp/wifi_status
    else
        echo "Reconnection not succesful, trying again in 1 minute" >> /tmp/wifi_status
    fi
   fi

Make it executable:

chmod +x /home/pi/scripts/keep_wifi_alive.sh

Now auto run the check every minute:

sudo crontab -e

*/1 * * * * sudo /home/pi/scripts/keep_wifi_alive.sh >/dev/null 2>&1

Strangely, the Rpi has a bug in crontab which requited te "sudo" above... Hell.. ugly, but it works ;)

Now the software configuration should be fine :) Reboot the Pi and start connecting the hardware... (instructions will be added when I find the time)