I have 4 of them in use: - 1 for the 3 phases of the house connection - 1 for the 3 phases of the solar system - 1 for each of the 3 phases of the 2 flats in the house This allows me to keep an eye on the production of the solar system, the electricity consumption of the flats and the consumption/feed-in to the grid in real time. Thanks to the integrated memory, I can also download the history at any time and visualise it with the tool of my choice.