I was wondering if somebody already found a working solution to create charts in openHAB 1.8.3 which shows a sum value per month of the last year. I'd like to give an example to clarify my requirements:
With my power meter I'm able to get the current power values every minute. This values are stored to rrd4j persistence service every minute. So far all charts are working and I'm also able to switch between day, week, month and year from within classic UI.
What I additionally need is a possibility to sum up or average all values e.g. per month and show a chart only of the sum values. It would be nice to get one value per month for power consumption to compare the different months per year. So the yearly chart should be based on 12 values.
I already know the usage of historic states function within rules. Maybe there is a already a working rule with some dummy items to write the appropriate values and create the chart afterwards?! I might be possible to create a rule at the end of each month, then sum up the values of current month and write it to rrd4j.
Do you know any other comfortable way to illustrate this kind of charts with rrd4j?
Thanks in advance!