[rrd-users] counting pellets with rrd

[Alex van den Bogaerdt]

----- Original Message ----- 
From: "Matthias Lemke" <m at box.li>
To: <rrd-users at lists.oetiker.ch>
Sent: Saturday, December 10, 2011 9:54 AM
Subject: [rrd-users] counting pellets with rrd


> Hello,
> 
> I connected my eta pellets heating unit via webservices to my home
> server. I am interesting in counting the amount of pellets per day (warm
> weather days should have low counts of pellets). The unit has a counter
> that counts from zero up forever... The unit sends the value in "kg".
> normally I have around 15...20 kg / day.
> I want to have a graph that shows me the kg/day. So I thought that I can
> write one data per day to the rrd. But, after two nights of testing and
> testing, I have no idea for the correct rrd setup...

In addition to what's already mentioned, don't forget that you need to modify the heartbeat setting from its default.

You say that you want to know the amount of pellets. RRDtool has no idea how many pellets weigh a kilogram, but if you know then you can tell RRDtool and show pellets per day. Just multiply (using a CDEF) by 86400 for 'per day' and by the amount of pellets per kg. This can be done in the same CDEF, even in the same multiplication.

HTH
Alex