Every power socket has a energy meter integrated, which returns an actual incremental power usage. Now I want to display the power usage per day/month/year. Therefore I created a rule for defining the old and the new day/month/year
when its 0:00 then set $variable_number_day_old = $variable_number_day_actual and set $variable_number_day_actual to date("DD") and set $variable_number_month_old = $variable_number_month_actual and set $variable_number_month_actual to date ("M") and set $variable_number_year_old = $variable_number_year_actual and set $variable_number_year_actual to date ("YYYY")
and a rule which always adds the power to an overall variable
when xxx.actualpower changes then overallactualpower =overallactualpower+xxx.actualpower
now I want to calculate the dayly power usage by
when variable_number_day_actual changes and variable_number_day_actual not equal to variable_number_day_old then day_power_new=overallactualpower- day_power_old
is this correct or any better idea?