[rrd-users] rrdtool and calculations

Steve Sykes steve at ecsykes.com
Sat Jun 23 16:11:38 CEST 2012

I am working on using rrdtool to log my water heater use.  I have a 
one-wire sensor measuring current and wish to calculate the wattage and 
eventually the KWH used.  The sensor reads from 0.09 for off and 3.36 
for 18 amps.  I am reading the data into the logging screen but don't 
know how to scale it up so that it reads amps instead of volts. Can 
rrdtool do this as it reads or will I have to pre-process the voltage 
before I send it to rrdtool?

Steve Sykes

More information about the rrd-users mailing list