You should see my cacti convertion script page for a script that takes output from ecmread.py and feeds it into cacti for graphing. But more generally this is the page that shows how to graph ECM1240 data with cacti

ecmread.py: the most current version of my modified ecmread with net metering
            (could be good or not)

ecmread-x.y.py: a snapshot(s) of the above, more likely to be "good"

ecm_addnamesx: I use
ecmread.py -p --serial --serialport /dev/ecm1| ecm_addnames1 | tee -a /var/log/ecmread1
This easily adds "labels" to your channels.

Enjoy,
Marc <marc_soft at merlins.org>

You'll find other code from Matt on his page (includes a few extras and database support).

This is an example of what you can graph: