VAV Press Click

VAV Press Click is a compact add-on board that contains a board-mount pressure sensor. This board features the LMIS025B, a low differential pressure sensor from First Sensor (part of TE Connectivity). It is based on thermal flow measurement of gas through a micro-flow channel integrated within the sensor chip. The innovative LMI technology features superior sensitivity, especially for ultra-low pressures ranging from 0 to 25Pa. The extremely low gas flow through the sensor ensures high immunity to dust contamination, humidity, and long tubing compared to other flow-based pressure sensors.

Click Product page

Click library

• Author : Nenad Filipovic
• Date : Mar 2021.
• Type : I2C type

Software Support

We provide a library for the VavPress 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 VavPress Click driver.

Standard key functions :

• vavpress_cfg_setup Config Object Initialization function.

  void vavpress_cfg_setup ( vavpress_cfg_t *cfg );

• vavpress_init Initialization function.

  VAVPRESS_RETVAL vavpress_init ( vavpress_t *ctx, vavpress_cfg_t *cfg );

• vavpress_default_cfg Click Default Configuration function.

  void vavpress_default_cfg ( vavpress_t *ctx );

Example key functions :

• vavpress_set_default_sensor_param VAV Press set default sensor parameter function.

  VAVPRESS_RETVAL vavpress_set_default_sensor_param ( vavpress_t *ctx, vavpress_sensor_param_data_t *param_data );

• vavpress_get_dif_press_and_temp VAV Press get differential pressure and temperature function.

  VAVPRESS_RETVAL vavpress_get_dif_press_and_temp ( vavpress_t *ctx, vavpress_sensor_param_data_t *param_data, float *diff_press, float *temperature );

• vavpress_retrieve_electronic_signature VAV Press retrieve electronic signature function.

  VAVPRESS_RETVAL vavpress_retrieve_electronic_signature ( vavpress_t *ctx, vavpress_el_signature_data_t *el_signature_data );

Example Description

This library contains API for the Vav Press Click driver. This demo application shows an example of differential pressure and temperature measurement.

The demo application is composed of two sections :

Application Init

Initialization of I2C module and log UART. After driver initialization and default settings, the app display retrieve the electronic signature and set the sensor parameters data.

void application_init ( void ) {
    log_cfg_t log_cfg;            /**< Logger config object. */
    vavpress_cfg_t vavpress_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_printf( &logger, "\r\n" );
    log_info( &logger, " Application Init " );

    // Click initialization.

    vavpress_cfg_setup( &vavpress_cfg );
    VAVPRESS_MAP_MIKROBUS( vavpress_cfg, MIKROBUS_1 );
    err_t init_flag = vavpress_init( &vavpress, &vavpress_cfg );
    if ( init_flag == I2C_MASTER_ERROR ) {
        log_error( &logger, " Application Init Error. " );
        log_info( &logger, " Please, run program again... " );

        for ( ; ; );
    }

    vavpress_default_cfg ( &vavpress );
    log_info( &logger, " Application Task " );
    Delay_ms ( 100 );

    vavpress_retrieve_electronic_signature( &vavpress, &el_signature_data );
    Delay_ms ( 100 );

    log_printf( &logger, "--------------------------------\r\n" );
    log_printf( &logger, " Firmware Version : %.3f        \r\n", el_signature_data.firmware_version );
    log_printf( &logger, " Pressure Range   : %d Pa       \r\n", el_signature_data.pressure_range );
    log_printf( &logger, " Part #           : %.11s       \r\n", el_signature_data.part_number );
    log_printf( &logger, " Lot #            : %.7s        \r\n", el_signature_data.lot_number );
    log_printf( &logger, " Output Type      : %c          \r\n", el_signature_data.output_type );
    log_printf( &logger, " Scale Factor     : %d          \r\n", el_signature_data.scale_factor );
    log_printf( &logger, " Calibration ID   : %.2s        \r\n", el_signature_data.calibration_id );
    log_printf( &logger, " Week number      : %d          \r\n", el_signature_data.week_number );
    log_printf( &logger, " Year number      : %d          \r\n", el_signature_data.year_number );
    log_printf( &logger, " Sequence number  : %d          \r\n", el_signature_data.sequence_number );
    log_printf( &logger, "--------------------------------\r\n" );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );

    param_data.scale_factor_temp = 72;
    param_data.scale_factor_press = el_signature_data.scale_factor;
    param_data.readout_at_known_temperature = 50;
    param_data.known_temperature_c = 24.0;
    Delay_ms ( 100 );
}

Application Task

This is an example that shows the use of a Vav Press Click board™. Logs pressure difference value [ Pa ] and temperature [ degree Celsius ] value. Results are being sent to the Usart Terminal where you can track their changes.

void application_task ( void ) {   
    err_t error_flag = vavpress_get_dif_press_and_temp( &vavpress, &param_data, &diff_press, &temperature );
    if ( error_flag == VAVPRESS_OK ) {
        log_printf( &logger, " Diff. Pressure    : %.4f Pa\r\n", diff_press );
        log_printf( &logger, " Temperature       : %.4f C\r\n", temperature );
        log_printf( &logger, "--------------------------------\r\n" );
        Delay_ms ( 1000 );
        Delay_ms ( 1000 );
    } else {
        log_error( &logger, " Communcation Error. " );
        log_info( &logger, " Please, run program again... " );

        for ( ; ; );
    }
}

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.VavPress

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.