The control unit enables local energy monitoring for the evaluation, storage and visualization of data from connected measuring devices, configuration of alarm values and manual and automated switching of inputs and outputs. The control unit has an integrated local web server and enables visualization of real-time values, historical values, system data and alarm messages on various end devices (PC, tablet, smartphone) in the network. 16 Modbus RTU participants (e.g. energy meters, network analysis devices, digital surge protection), 16 Modbus TCP participants and 32 InSite bus participants (current sensors, I/O modules, digital auxiliary switches) can be connected. The device can be expanded modularly to provide additional functions. The measurement data can be exported via CSV file, email or FTP or passed on to higher-level energy management systems or building management systems via REST API or Modbus.