The feed-in meter is a calibrated measuring instrument and a legally required component of every grid-connected photovoltaic system. It is generally provided by the grid operator and installed in the metering cabinet directly behind the grid connection point. In full feed-in configurations, the entire generated energy is reported to and remunerated by the utility via this meter. In self-consumption systems, bidirectional meters measure both fed-in and drawn grid energy separately. With the introduction of smart meter gateways, traditional Ferraris meters are being gradually replaced by digital meters enabling remote reading and tamper-proof measurement.