SLAA494B May 2011 – September 2023 MSP430AFE221 , MSP430AFE222 , MSP430AFE223 , MSP430AFE231 , MSP430AFE232 , MSP430AFE233 , MSP430AFE251 , MSP430AFE252 , MSP430AFE253
This application report describes the implementation of a single-phase electronic electricity meter using the Texas Instruments MSP430AFE2xx metering processors. It includes the necessary information with regard to metrology software and hardware procedures for this single chip implementation.
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Project collateral and source code discussed in this application report can be downloaded from the following URL: http://www.ti.com/lit/zip/slaa494.
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The MSP430AFE2xx devices belong to the MSP430F2xx family of devices. These devices find their application in energy measurement and have the necessary architecture to support it. The MSP430AFE2xx devices have a powerful 12-MHz central processing unit (CPU) with MSP430 CPUX architecture. The analog front end consists of up to three analog-to-digital converters (ADCs) based on a second-order sigma-delta (ΣΔ) architecture that supports differential inputs. The ΣΔ ADCs (SD24) can output 24-bit results. They can be grouped together for simultaneous sampling of voltage and current on the same trigger. Each SD24 converter supports a common-mode voltage of up to -1 V and enables all sensors to be referenced to ground. In addition, it has an integrated gain stage that supports gains up to 32 for amplification of low-output sensors. A 16-bit x 16-bit hardware multiplier on this chip can be used to further accelerate math-intensive operations during energy computation. The software supports calculation of various parameters for single-phase energy measurement. The key parameters calculated during energy measurements are root mean square (RMS) current and voltage, active and reactive power and energy, power factor, and frequency. This application report has the complete metrology source code provided as a zip file. For new designs, download the Energy Measurement Design Center (EMDC) and software library from MSP-EM-DESIGN-CENTER.