Implementing multi-phase Rogowski-based e-meter

The MSP430F471xx devices belong to the MSP430F4xx family of devices. These devices find its application in energy measurement and have the necessary architecture to support it. The MSP430F471xx devices have a powerful 16MHz CPU with MSP430CPUx architecture. The analogue front end consists of up to seven analogue to digital converters (ADC) based on a second order sigma-delta architecture that supports differential inputs. The sigma-delta ADCs (SD16) that have a resolution of 16- bits can be configured and grouped together for simultaneous sampling of voltages and currents on the same trigger. Each SD16 supports a common mode voltage of up to -1 V and enables all sensors to be referenced to ground. In addition, it also has an integrated gain stage to support gains up to 32 for amplification of low-output sensors. A 32bit x 32bit HW multiplier on this chip can be used to further accelerate math intensive operations during energy computation. The software supports calculation of various parameters for total three phase and for each individual phases. The key parameters calculated during energy measurements are: RMS current and voltage, active and reactive energy and frequency.

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Originally published by Texas Instruments Inc. at www.ti.com as "Multi-Phase Rogowski-Based E-Meter".