RX21A reference platform to easily design economical, highly-functional smart electricity meters

The reference platform for smart electricity meter design based on Renesas RX21A 32-bit microcontrollers (MCUs) offers developers a broad range of options such as a modular design supporting both 3-phase 4 wire and single-phase operation, and configurable sensor types including current transformer.

This enables it to operate at nominal 230 V 50 Hz to 60 Hz, with full 100 mA to 100 A measurement range. Accuracy is equivalent to IEC62053-22 (and ANSI C12.20), to at least 0.5 s, and compliant with IEC6205-23, class 2 reactive.

A full set of metrology libraries is provided, enabling precision measurement of voltage and current on each phase, active and reactive power on each phase, and apparent and harmonic power on each phase. Power quality measurement functions such as voltage sag are also provided.

Key software features include single point calibration for the 24-bit precision A/D converter (ADC) and analogue front-end (AFE), and temperature compensation for the AFE including programmable gain amplifier (PGA) and ADC, voltage reference, and real time clock.

Data exchange can be carried out via the IEC62056-21 optical port and isolated USB virtual COM port. A user-friendly, multi-function graphical display and an intuitive PC graphical user interface allow easy operation.

The RX21A Group of MCUs implements in a single chip functions that previously required separate devices, such as power measurement, meter control, calculation of electricity charges, and data encryption. This reduces the number of external components required for the implementation of a complete smart meter and thus not only simplifies the design, but also helps to lower the overall cost.

The RX21A electricity meter reference platform is available in limited quantities. Detailed information can be requested by sending an email to

Source: MSC Vertriebs GmbH