Features

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Compliant to EN 50470-x, IEC 62053-2x, ANSI12.2x standard requirements for

AC watt meters

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Active wideband, active fundamental, reactive and apparent power/energy

calculation for each phase and cumulative

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Accuracy Class 0.5 according to IEC 62053-22 on 3-ph active/apparent power

measurement

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Accuracy Class 1 according to IEC 62053-21 on 3-ph reactive power

measurement

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6 channels voltage and current decimated samples available @200 us

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5 kHz measurement bandwidth

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RMS and THD (optional) calculation of each voltage and current signal

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Selectable high pass filter for DC measurement

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Line period and phase shift measurement for each phase

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Phase voltage delays

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Full calibration (amplitude, power offset and samples offset for DC

measurement)

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Two configurable LED for pulsed outputs

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Communication through USB in virtual com port mode with shell commands

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6 kV galvanic isolation between the phases with 8 mm creepage and clearance

Description

The EVALSTPM-3PHISO evaluation board implements a complete three-phase

energy meter with low-cost shunt current sensors.

The solution is based on the STPMS2 device, a double channel, 24-bits second

order sigma-delta modulator, measuring voltage and current for each phase through

a voltage divider and a shunt current sensor. Sensing circuitry and PCB layout are

optimized to maximize signal-to-noise ratio for optimal accuracy.

The STPMS2 oversamples the signal using a 4 MHz clock distributed in a

synchronized way by the microcontroller and outputs voltage and current sigma-delta

bitstreams, multiplexed on the same pin.

The two-wire communication between STPMS2 modulator and MCU is isolated by

STISO621W, 6 kV galvanic isolated interface, allowing up to 100 Mbps rate and low

pulse distortion (<3ns) for safe and fast data transfer between isolated domains.

The FW embedded in the solution exploits the DFSDM filters of the STM32F413RH

to convert the six bitstreams into 24-bits voltage and current data, at 200 us rate. All

the metrology parameters are computed real time on a 200 us basis.

Two LEDs are available for active and reactive pulses generation.

The FW also implements a virtual com port communication to easily access the

internal parameters to read metrology data, to modify the internal configuration for a

high flexibility of the application, and to calibrate the board.

Product status link

EVALSTPM-3PHISO

Three-phase full shunt electricity meter evaluation board based on STPMS2,

STISO621W and STM32F413RH

EVALSTPM-3PHISO

Data brief

DB4332 - Rev 1 - October 2020

For further information contact your local STMicroelectronics sales office.

www.st.com