do_fhem/fhem/core/www/gplot/co20.gplot

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# Display the current voc (volatile organic compounds) value in three color gradients.
# Corresponding FileLog definition: 
# define <fileLogDefinitionName> FileLog ./log/co20-%Y-%m.log <co20 sensor name>
# define <webLinkDefinitionName> SVG <fileLogDefinitionName>:co20:CURRENT
# attr <webLinkDefinitionName> label "Air quality - Min $data{min1}, Max $data{max1}, Last $data{currval1}"

set terminal png transparent size <SIZE> crop
set output '<OUT>.png'
set xdata time
set timefmt "%Y-%m-%d_%H:%M:%S"
set xlabel " "
set title '<L1>'
set ytics "good" 750, "ok" 1250, "bad" 1750
set y2tics "" 1000,"" 1500
set grid y2tics
set ylabel ""
set y2label "Air quality (ppm)"
set yrange [450:2000]
set y2range [450:2000]

#FileLog 4:voc::
#FileLog 4:voc::$fld[3]>1000?1000:$fld[3]
#FileLog 4:voc::$fld[3]>1500?1500:$fld[3]
#FileLog 4:voc::$fld[3]>2000?2000:$fld[3]

plot "<IN>" using 1:2 axes x1y2 title 'Air quality (ppm)' ls l5 lw 0.2 with lines,\
     "<IN>" using 1:2 axes x1y2 title ' ' ls l1fill lw 0.2 with lines,\
     "<IN>" using 1:2 axes x1y2 title ' ' ls l4fill lw 0.2 with lines,\
     "<IN>" using 1:2 axes x1y2 title ' ' ls l0fill lw 0.2 with lines