set size .95, 1
set term png size 1000, 300
set output 'xantrex_nightly.png'
set xdata time
set timefmt "%b %d %H:%M:%S %Y"
set title "Daily Energy Harvest 2011"
set ylabel "kWhr" 
set yrange [0:20]
set xrange ["Jan 1 00:00:00 2011":"Dec 31 00:00:00 2011"]
set xlabel " "
set grid
# set key top left

plot     'xantrex_nightly.data' using 1:5 t "Fixed Power" with lines lc rgb "red", \
     'xantrex_nightly.data' using 1:6 t "Tracking Power" with lines lc rgb "green", \
     'xantrex_nightly.data' using 1:(($5 + $6)) t "Total Power" with lines lc rgb "black"