Hello all, I have just installed a bunch of sensor stuff my friend made for me to measure my electricity usage. The sensor tells the computer when my electricity meter flashes, and a number in a text file is increased by one. Every minute, the value is inserted in a RRD as a counter. One flash from the meter represents 1/800th of a kW. I modified my y axis to show the correct value - multiply by 1250 to give watts (I don't know why I have to multiply by a thousand to give watts, as if I multiply by 1.25, I can see a "m" in front of the values). Anyway, I'd like to see the maximum, average and minimum values at the bottom of the graph - I've discovered GPRINT, but it shows the wrong value. For the life of me, I can't figure out how to modify the values to show watts, instead of counts. Currently, the graph shows a line going between 230 watts and 185 watts. The output from GPRINT shows 0.18 for max, 0.17 for average and 0.15 for min. I know I need to multiply those 3 values by 1250 to show the correct figures, but how? I tried making a new variable and doing calculations on it, but doesn't seem to work. The line in my script to create the graph is:
rrdtool graph -w 800 -h 250 --vertical-label "Watts" /home/piers/ software/rrdtool/leccyday.png DEF:usage=/home/piers/software/rrdtool/ meter.rrd:meter:MAX CDEF:realusage=usage,1250,\* LINE1:realusage#0000FF VDEF:usagemax=usage,MAXIMUM GPRINT:usagemax:"Max\: %lfw" > /dev/null I tried inserting a snippet "CDEF:usagemax2=usagemax,1250,*" but I got "ERROR: rpn expressions without DEF or CDEF variables are not supported" What am I doing wrong here, and how do I fix this? Thanks very much for your time! Regards - Piers _______________________________________________ rrd-users mailing list [email protected] https://lists.oetiker.ch/cgi-bin/listinfo/rrd-users
