Accumulator example

HTML entities are fine here: (Σ → Σ)

Define all your required channels, put this all together and you should have the following definition:

Please note:

• The real sensor channels storing the data for P_AC, P_DC1, P_DC2 etc. must be defined for each inverter!
• The grouping channels Inverter efficiency [%] and Σ Pdc [W] must be defined only once!
  They find out their correct child channels from their position in the channel tree on request.

If you want to have a more detailed result for efficiency, set the valid from attribute for example to 95:

Here you can see, that the efficiency (black dashed) is after noon about 97%!

All values below 95% are "raised" to 95%, so just ignore them until 8:00...