Renesas Electronics Europe is making available a full reference platform for the RX21A Group of 32-bit microcontrollers (MCUs) for smart electricity meters with advanced functionality. The RX21A meter reference platform comprises a full development support environment including middleware for power measurement and calibration tools, enabling developers to easily design ultra-compact smart electricity meters allowing short time-to-market.
Key hardware features include 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 230V 50Hz~60Hz, with full 100mA to 100A measurement range. Accuracy is equivalent to IEC62053-22 (and ANSI C12.20), to at least 0.5s, 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 (also known as IEC1107) 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 and helps to lower the overall cost. In addition, the RX21A Group includes product versions for a variety of meter models, allowing common and effective system design.