Identify and address power quality issues promptly with ACS37800 and STM32L073RZ
Track and analyze power usage trends
Published Feb 26, 2024
Click board™
PWR Meter 3 Click - 90A
Dev Board
Nucleo-64 with STM32L073RZ MCU
Compiler
NECTO Studio
MCU
STM32L073RZ
Our solution is designed to accurately measure voltage and current through your connected load, providing critical insights into electrical performance
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Hardware Overview
How does it work?
PWR Meter 3 Click is based on the ACS37800, a simple solution for voltage, current, and power monitoring from Allegro MicroSystems, which simplifies the addition of power monitoring in 60Hz to many AC/DC applications. The ACS37800 includes a copper conduction path that generates a magnetic field proportional to the applied current, sensed differentially to reject errors introduced by common mode fields. It is particularly well suited for high isolation, achieving reinforced isolation ratings of 4800 VRMS and a reliable ±90A bidirectional current sensing range. With high configurability and integrated features, this Click board™ can fit most power monitoring applications. The ACS37800 measures the voltage applied to the REF terminal, in the range from 9.5 to 27V, by resistor dividing it down to fit the input range of the onboard voltage sense amplifier and
add isolation. On the other hand, the current applied to the current sensing terminals is measured using the integrated current loop and galvanically isolated Hall sensor. Both analog signals are then sampled using integrated high-accuracy ADCs before entering the digital system. The metrology engine later determines the frequency, calculates RMS values of current, voltage, and power, and provides a range of averaging and configuration options. PWR Meter 3 Click communicates with an MCU using the standard I2C 2-Wire interface to read data and configure settings, supporting Standard Mode operation with a clock frequency of 100kHz and Fast Mode up to 400kHz. The ACS37800 can be turned on, or off through the EN pin routed to the RST pin of the mikroBUS™ socket, hence offering a switch operation to turn ON/OFF power delivery
to the ACS37800 via TPS2041B. Along with the ability to measure current and voltage, it also has two LED indicators, DIO0 and DIO1, for the realization of visual detection of some anomalies in operation, such as undervoltage and overvoltage reporting, and fast overcurrent fault detection. The DIO0 LED default state application is for zero crossing, while DIO1 stands for overcurrent detection. In addition to the LEDs, this information can be detected through the INT and AN pins of the mikroBUS™ socket, marked as D0 and D1. This Click board™ can be operated only with a 3.3V logic voltage level. The board must perform appropriate logic voltage level conversion before using MCUs with different logic levels. Also, it comes equipped with a library containing functions and an example code that can be used as a reference for further development.
Features overview
Development board
Nucleo-64 with STM32L073RZ MCU offers a cost-effective and adaptable platform for developers to explore new ideas and prototype their designs. This board harnesses the versatility of the STM32 microcontroller, enabling users to select the optimal balance of performance and power consumption for their projects. It accommodates the STM32 microcontroller in the LQFP64 package and includes essential components such as a user LED, which doubles as an ARDUINO® signal, alongside user and reset push-buttons, and a 32.768kHz crystal oscillator for precise timing operations. Designed with expansion and flexibility in mind, the Nucleo-64 board features an ARDUINO® Uno V3 expansion connector and ST morpho extension pin
headers, granting complete access to the STM32's I/Os for comprehensive project integration. Power supply options are adaptable, supporting ST-LINK USB VBUS or external power sources, ensuring adaptability in various development environments. The board also has an on-board ST-LINK debugger/programmer with USB re-enumeration capability, simplifying the programming and debugging process. Moreover, the board is designed to simplify advanced development with its external SMPS for efficient Vcore logic supply, support for USB Device full speed or USB SNK/UFP full speed, and built-in cryptographic features, enhancing both the power efficiency and security of projects. Additional connectivity is
provided through dedicated connectors for external SMPS experimentation, a USB connector for the ST-LINK, and a MIPI® debug connector, expanding the possibilities for hardware interfacing and experimentation. Developers will find extensive support through comprehensive free software libraries and examples, courtesy of the STM32Cube MCU Package. This, combined with compatibility with a wide array of Integrated Development Environments (IDEs), including IAR Embedded Workbench®, MDK-ARM, and STM32CubeIDE, ensures a smooth and efficient development experience, allowing users to fully leverage the capabilities of the Nucleo-64 board in their projects.
Microcontroller Overview
MCU Card / MCU
Architecture
ARM Cortex-M0
MCU Memory (KB)
192
Silicon Vendor
STMicroelectronics
Pin count
64
RAM (Bytes)
20480
You complete me!
Accessories
Click Shield for Nucleo-64 comes equipped with two proprietary mikroBUS™ sockets, allowing all the Click board™ devices to be interfaced with the STM32 Nucleo-64 board with no effort. This way, Mikroe allows its users to add any functionality from our ever-growing range of Click boards™, such as WiFi, GSM, GPS, Bluetooth, ZigBee, environmental sensors, LEDs, speech recognition, motor control, movement sensors, and many more. More than 1537 Click boards™, which can be stacked and integrated, are at your disposal. The STM32 Nucleo-64 boards are based on the microcontrollers in 64-pin packages, a 32-bit MCU with an ARM Cortex M4 processor operating at 84MHz, 512Kb Flash, and 96KB SRAM, divided into two regions where the top section represents the ST-Link/V2 debugger and programmer while the bottom section of the board is an actual development board. These boards are controlled and powered conveniently through a USB connection to program and efficiently debug the Nucleo-64 board out of the box, with an additional USB cable connected to the USB mini port on the board. Most of the STM32 microcontroller pins are brought to the IO pins on the left and right edge of the board, which are then connected to two existing mikroBUS™ sockets. This Click Shield also has several switches that perform functions such as selecting the logic levels of analog signals on mikroBUS™ sockets and selecting logic voltage levels of the mikroBUS™ sockets themselves. Besides, the user is offered the possibility of using any Click board™ with the help of existing bidirectional level-shifting voltage translators, regardless of whether the Click board™ operates at a 3.3V or 5V logic voltage level. Once you connect the STM32 Nucleo-64 board with our Click Shield for Nucleo-64, you can access hundreds of Click boards™, working with 3.3V or 5V logic voltage levels.
Used MCU Pins
mikroBUS™ mapper
Take a closer look
Schematic
Step by step
Project assembly
Start by selecting your development board and Click board™. Begin with the Nucleo-64 with STM32L073RZ MCU as your development board.
Track your results in real time
Application Output via Debug Mode
1. Once the code example is loaded, pressing the "DEBUG" button initiates the build process, programs it on the created setup, and enters Debug mode.
2. After the programming is completed, a header with buttons for various actions within the IDE becomes visible. Clicking the green "PLAY" button starts reading the results achieved with the Click board™. The achieved results are displayed in the Application Output tab.
Software Support
Library Description
This library contains API for PWR Meter 3 Click driver.
Key functions:
pwrmeter3_get_dio0_pin- This function returns the DIO0 pin logic statepwrmeter3_get_dio1_pin- This function returns the DIO1 pin logic statepwrmeter3_read_average_rms- This function reads the voltage and current RMS measurements averaged from a specified number of samples
Open Source
Code example
This example can be found in NECTO Studio. Feel free to download the code, or you can copy the code below.
/*!
* @file main.c
* @brief PWR Meter 3 Click example
*
* # Description
* This example demonstrates the use of PWR Meter 3 click board by reading and displaying
* the voltage, current, and power RMS measurements.
*
* The demo application is composed of two sections :
*
* ## Application Init
* Initializes the driver and performs the click default configuration which sets the DC measurement
* and VRMS thresholds to about 28V for overvoltage and about 9.3V for undervoltage flag.
*
* ## Application Task
* Reads the voltage and current RMS values averaged from 500 samples, then calculates the power from it
* and displays the results on the USB UART. Also if an UV or OV flag is detected it will be logged accordingly.
*
* @author Stefan Filipovic
*
*/
#include "board.h"
#include "log.h"
#include "pwrmeter3.h"
static pwrmeter3_t pwrmeter3;
static log_t logger;
void application_init ( void )
{
log_cfg_t log_cfg; /**< Logger config object. */
pwrmeter3_cfg_t pwrmeter3_cfg; /**< Click config object. */
/**
* Logger initialization.
* Default baud rate: 115200
* Default log level: LOG_LEVEL_DEBUG
* @note If USB_UART_RX and USB_UART_TX
* are defined as HAL_PIN_NC, you will
* need to define them manually for log to work.
* See @b LOG_MAP_USB_UART macro definition for detailed explanation.
*/
LOG_MAP_USB_UART( log_cfg );
log_init( &logger, &log_cfg );
log_info( &logger, " Application Init " );
// Click initialization.
pwrmeter3_cfg_setup( &pwrmeter3_cfg );
PWRMETER3_MAP_MIKROBUS( pwrmeter3_cfg, MIKROBUS_1 );
if ( I2C_MASTER_ERROR == pwrmeter3_init( &pwrmeter3, &pwrmeter3_cfg ) )
{
log_error( &logger, " Communication init." );
for ( ; ; );
}
if ( PWRMETER3_ERROR == pwrmeter3_default_cfg ( &pwrmeter3 ) )
{
log_error( &logger, " Default configuration." );
for ( ; ; );
}
log_info( &logger, " Application Task " );
}
void application_task ( void )
{
float v_rms, i_rms;
if ( PWRMETER3_OK == pwrmeter3_read_average_rms ( &pwrmeter3, &v_rms, &i_rms, PWRMETER3_DEF_AVG_SAMPLES ) )
{
if ( !pwrmeter3_get_dio0_pin ( &pwrmeter3 ) )
{
log_printf ( &logger, " Over-voltage detected!\r\n" );
}
if ( !pwrmeter3_get_dio1_pin ( &pwrmeter3 ) )
{
log_printf ( &logger, " Under-voltage detected!\r\n" );
}
log_printf ( &logger, " Voltage: %.2f V\r\n", v_rms );
log_printf ( &logger, " Current: %.2f A\r\n", i_rms );
log_printf ( &logger, " Power: %.2f W\r\n\n", i_rms * v_rms );
}
}
void main ( void )
{
application_init( );
for ( ; ; )
{
application_task( );
}
}
// ------------------------------------------------------------------------ END
