RMS to DC 2 Click

RMS to DC 2 Click is a compact add-on board that converts the RMS of the input signal into a DC voltage. This board features the AD8436, a low-cost, low-power, true RMS-to-DC converter from Analog Devices. The AD8436 is a translinear precision, low-power, true RMS-to-DC converter that delivers true RMS or average rectified value of AC waveform. It features high accuracy, a wide dynamic input range (100μV rms to 3V rms), a wide bandwidth of up to 1MHz, and more. This Click board™ makes the perfect solution for the development of various true RMS digital multimeter applications, panel meters and gauges, AC + DC measurement applications, a true RMS measurement of an audio signal, and other similar applications that require accurate RMS value readings.

Click Product page

Click library

• Author : Stefan Filipovic
• Date : Apr 2023.
• Type : ADC/I2C type

Software Support

We provide a library for the RMS to DC 2 Click as well as a demo application (example), developed using MikroElektronika compilers. The demo can run on all the main MikroElektronika development boards.

Package can be downloaded/installed directly from NECTO Studio Package Manager(recommended way), downloaded from our LibStock™ or found on Mikroe github account.

Library Description

This library contains API for RMS to DC 2 Click driver.

Standard key functions :

• rmstodc2_cfg_setup Config Object Initialization function.

  void rmstodc2_cfg_setup ( rmstodc2_cfg_t *cfg );

• rmstodc2_init Initialization function.

  err_t rmstodc2_init ( rmstodc2_t *ctx, rmstodc2_cfg_t *cfg );

Example key functions :

• rmstodc2_set_vref This function sets the voltage reference for RMS to DC 2 Click driver.

  err_t rmstodc2_set_vref ( rmstodc2_t *ctx, float vref );

• rmstodc2_read_voltage This function reads raw ADC value and converts it to proportional voltage level.

  err_t rmstodc2_read_voltage ( rmstodc2_t *ctx, float *voltage );

Example Description

This example demonstrates the use of the RMS to DC 2 Click board by measuring the RMS voltage of the input signal.

The demo application is composed of two sections :

Application Init

Initializes the driver and logger.

void application_init ( void )
{
    log_cfg_t log_cfg;  /**< Logger config object. */
    rmstodc2_cfg_t rmstodc2_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.
    rmstodc2_cfg_setup( &rmstodc2_cfg );
    RMSTODC2_MAP_MIKROBUS( rmstodc2_cfg, MIKROBUS_1 );
    err_t init_flag = rmstodc2_init( &rmstodc2, &rmstodc2_cfg );
    if ( ( ADC_ERROR == init_flag ) || ( I2C_MASTER_ERROR == init_flag ) )
    {
        log_error( &logger, " Communication init." );
        for ( ; ; );
    }

    log_info( &logger, " Application Task " );
}

Application Task

Reads the RMS voltage of the input signal and displays the results on the USB UART approximately once per second.

void application_task ( void )
{
    float voltage = 0;
    if ( RMSTODC2_OK == rmstodc2_read_voltage ( &rmstodc2, &voltage ) ) 
    {
        log_printf( &logger, " RMS voltage : %.3f[V]\r\n\n", voltage * RMSTODC2_RMS_VOLTAGE_COEF );
        Delay_ms ( 1000 );
    }
}

The full application code, and ready to use projects can be installed directly from NECTO Studio Package Manager(recommended way), downloaded from our LibStock™ or found on Mikroe github account.

Other Mikroe Libraries used in the example:

• MikroSDK.Board
• MikroSDK.Log
• Click.RMStoDC2

Additional notes and informations

Depending on the development board you are using, you may need USB UART Click, USB UART 2 Click or RS232 Click to connect to your PC, for development systems with no UART to USB interface available on the board. UART terminal is available in all MikroElektronika compilers.