Renesas design targets RX21A MCU at smart meters
The reference platform’s hardware supports both 3-phase 4 wire and single-phase operation, and configurable sensor types including current transformer.
The intention is to allow 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.
The middleware for power measurement includes a set of metrology libraries, 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. Other 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. There is also a multi-function graphical display and an intuitive PC graphical user interface.
Renesas is presenting the RX21A meter reference platform on its stand (A8) at Smart Grids Paris on 4th June.