Thanks to Schmuzli!
With his timer experience I wrote the data logger for weather data. It is logging hourly the weather values for temperature, wind speed, pressure... and is showing these data as a curve for the last week.
I could do some adjustments to make it work for energy data on RS232. If you are using the KNX/EIB system you may also use it with our IP gateway.
See the " target="_blank">youtube film