The Delta R1E is designed to work with the Delta RPI Inverter range to provide a local monitoring point for your solar system. It can be combined with the P1E to measure total household consumption and production as well as enabling the zero-export function if required.
Additionally, a partial export function is available in the latest R1E FW (2.01). This is an aggregate export limitation that can be used in 3-phase and single phase applications.