set terminal png
set output 'xantrex_nightly.png'
set xdata time
set timefmt "%b %d %H:%M:%S %Y"
set title "Daily Energy Harvest"
set ylabel "kWhr" 
set yrange [0:40]
set xrange [*:*]
set xlabel " "
set grid
set size 1.2 ,0.5
# set key top left

plot     'xantrex_nightly.data' using 1:(($5 + $6)) t "Total Power" with lines lc rgb "black"