Hi. First of all, let me explain, what i'm planing to do: i've got some data of a lightsensor, measuring the irradiation. these values are measured in watt/m^2 and are fed into a rrd-database every 60 seconds.
now i want to calculate the amount of energy in total which is collected by this sensor since a chosen time... measured in watt*s. (i know the size of the surface area of that sensor.) and i dont want only one value for a day, i want to have the run of the curve of the energy. So what i really need is a function to integrate the function of received energy. Here is what i tried to do to build the sum of all values of the past: [using rrdtool graph] DEF:Ls=Light.rrd:D1:AVERAGE CDEF:E=PREV,Ls,60,*,+ LINE:E#FF0000 but it wont work .. E is allways 0 or not defined [i dont see any line]. i think the PREV-Function isnt working for non "DEF-Values"..inconsistent with the manual-page. using VDEF:E=Ls,TOTAL gives me only one constant value for the whole graph - but not the curve. Can you help me? PS: I think a SUM-ConsolidationFunction could be useful for problems like this.. Yours, Rene. _______________________________________________________________________ Viren-Scan für Ihren PC! Jetzt für jeden. Sofort, online und kostenlos. Gleich testen! http://www.pc-sicherheit.web.de/freescan/?mc=022222 -- Unsubscribe mailto:[EMAIL PROTECTED] Help mailto:[EMAIL PROTECTED] Archive http://lists.ee.ethz.ch/rrd-users WebAdmin http://lists.ee.ethz.ch/lsg2.cgi
