[rrd-users] Question about averaging daily ; but with 5 min. steps

[Jean-Yves Avenard]

Hi

Okay, it looks we started on the wrong foot so I'm going to explain
the problem differently...

I am measuring two things.
One is the power usage of all my electrical appliances ; the other is
the wattage output of my solar panel.

Say my electrical appliances are using 500W of power ; 24/7. So that
makes it 500 * 24 / 1000 = 12kWh per day.

Now my solar generates 1000W for 10 minutes every hour on the hour...
So that makes it 1000 * 10 / 60 * 24 / 1000 = 4kWh per day.

If I was to calculate how much energy I put back in the grid ; using
daily average ; it would show as 0 ; as 12kWh > 4kWh

However, if I use 5 minutes average (the same calculation as performed
by the electric meter) the amount of energy put back in the grid is:
(1000 - 500) * 10 / 60 * 24 / 1000 = 2kWh per day.

Going back to RRD ;

If I do:
DEF:total=currentcost3.rrd:total:AVERAGE \
DEF:total30=currentcost3.rrd:total:AVERAGE:step=300 \
DEF:solar=solarprod3.rrd:total:AVERAGE \
DEF:solar30=solarprod3.rrd:total:AVERAGE:step=300 \
   CDEF:totalw=total,3600,/ CDEF:total30w=total30,3600,/ \
   CDEF:ctotal=totalw,$res,* \
   CDEF:ctotal30=total30w,$res,* \
   CDEF:ctotaltot=total30w,UN,0,total30w,IF,$duration,* \
   CDEF:csolar=solar,$res,* \
   CDEF:csolar30=solar30,$res,* \
   CDEF:csolartot=solar30,UN,0,solar30,IF,$duration,* \
   CDEF:cimport=ctotal,csolar,UN,0,csolar,IF,-,0,MAX \
   CDEF:cimport30=ctotal30,csolar30,UN,0,csolar30,IF,-,0,MAX \
   CDEF:cimporttot=total30w,UN,0,total30w,IF,solar30,UN,0,solar30,IF,-,0,MAX,$duration,*
\
   CDEF:cexport=csolar,UN,0,csolar,IF,ctotal,-,0,MAX \
   CDEF:cexport30=csolar30,UN,0,csolar30,IF,ctotal30,-,0,MAX \
   CDEF:cexporttot=solar30,UN,0,solar30,IF,total30w,UN,0,total30w,IF,-,0,MAX,$duration,*
\
   VDEF:vimportmax=cimport,MAXIMUM \
   VDEF:vimportavg=cimport30,AVERAGE \
   VDEF:vimportmin=cimport,MINIMUM \
   VDEF:vimporttot=cimporttot,AVERAGE \
   VDEF:vexportmax=cexport,MAXIMUM \
   VDEF:vexportavg=cexport30,AVERAGE \
   VDEF:vexportmin=cexport,MINIMUM \
   VDEF:vexporttot=cexporttot,AVERAGE \
 COMMENT:'            ' \
 COMMENT:'Maximum    ' \
   COMMENT:'Average    ' \
   COMMENT:'Minimum    '  \
   COMMENT:'Total View\l'  \
   AREA:cimport#ff4500:'Import  ' \
   GPRINT:vimportmax:'%6.1lf %sWh ' \
   GPRINT:vimportavg:'%6.1lf %sWh ' \
   GPRINT:vimportmin:'%6.1lf %sWh  ' \
   GPRINT:vimporttot:'%7.2lf %sWh\l' \
   AREA:cexport#FFd700a0:'Export  ' \
   GPRINT:vexportmax:'%6.1lf %sWh ' \
   GPRINT:vexportavg:'%6.1lf %sWh ' \
   GPRINT:vexportmin:'%6.1lf %sWh  ' \
   GPRINT:vexporttot:'%7.2lf %sWh\l' \

With this ; the average and total output are calculated properly;
because I'm using a 5 minutes interval at all times
DEF:solar30=solarprod3.rrd:total:AVERAGE:step=300

However, this isn't giving me the graph I want (it would show a 5
minutes average graph, and not a daily average graph) and same for
maximum and minimum : those would be the maximum of a 5 minutes
average and not the maximum of a daily average...

So back to my original question:
How do I graph with RRD ; a daily average made on a 5 minutes average
of a substraction of 2 values of two different RRD input.
And is this even possible currently ?

Thanks !
Jean-Yves