I recently came across a blog article from Aleksandr Kovalenko, an engineer at Plarium in Kharkiv, explaining how to collect electricity consumption from a SDM-220 RS485/Modbus meter, integrate it to openHAB and graph them with HABPanel’s Chart widget.
The trick used to represent peak/off-peak hours is quite noteworthy!
Here’s a link to the article:
…and if you don’t read Russian, this site has a rough translation:
Kudos to you Aleksandr if you happen to read this!