This draft European Standard describes the primary purpose of the EMS, which is to meter energy consumption for billing and provide compiled energy billing data (CEBD) to a DCS. The EMS may also be used for other functions such as energy management. In addition, this draft European Standard also describes the primary purpose of a DCS and its interactions with an EMS and settlement system. This part of EN 50463: " gives requirements for the complete Energy Measurement System and also requirements for all devices implementing one or more functions of the Energy Measurement System; " applies to newly manufactured Energy Measurement Systems for use on board railway traction units, powered by a.c. and/or d.c. supply voltages as listed in EN 50163; " does not apply to portable Energy Measurement Systems.