csvfilter is used

installable
pip install csvfilter





csvfilter -f (fields you want)

you want the 500 number to the right. 
so
csvfilter -f 6,8,10 062918_homesolar.txt > output.csv
as an example


then
sed 's/,/ /g' output.csv > output2.csv

to make it ready for gnuplot

then
gnuplot loadme_HomeSolar