Smart meter platform, with billing functions, from Renesas

October 29, 2014 // By Graham Prophet
Renesas Electronics’ “Bill It! – Smart Meter RX21A” polyphase meter reference platform is a reference design that removes the need for designers to create their own metrology and calibration routines, required for a billing polyphase meter design, while complying with the most stringent IEC norms.

“Bill It! – Smart Meter RX21A” is based on Renesas' RX21A group of microcontrollers (MCUs), and integrates the metrology front end and the application processor in a single chip. The RX21A group devices are equipped with three, four or seven independent 24-bit delta-sigma analogue-digital converters (ΔΣ-ADC). They can accommodate single-phase, split-phase and three-phase-plus-neutral billing electricity meters, respectively. The ΔΣ-ADC channels include a programmable gain amplifier (PGA), which allows the target meter to cover a dynamic range between 10 mA and 100A at enhanced temperature range. By storing calibration data in the flash, the RX21A devices cover applications better than Class 0.2S, thus exceeding the most stringent IEC metering requirement presently available, the IEC62053-22.

Renesas says it has designed the “Bill It! – Smart Meter RX21A” for a very wide target specification, allowing for easy implementation and eventual downsizing to a billing electricity meter design tailored to the customer’s needs. The design is built and supported entirely in Europe, and fulfils all required Cenelec standards for EMC and safety.

The solution includes an intuitive PC graphical user interface (GUI), providing engineers during the design phase with all the information they need to trim and analyse the data measured by the ΔΣ-ADC channels. This covers both graphical feedback from the ADC data as well as prepared data after the calibration steps, frequency analysis and separation of active/reactive energy use.

Each kit contains the Bill It! Polyphase Meter, a CD-ROM including the embedded metrology and calibration software source code, the PC GUI, the board schematics, the bill of materials, Gerber files, user manual, quick start guide and the electrical connection setup needed to use the electricity meter.

Renesas adds that this introduction marks the next step in the company’s strategy of being a solution provider. It does this by providing all the required components, comprising both hardware and software, to enable designers and engineers to re-use proven solutions for their target application, reduce