VAV Press Click

NOTE: Keeping in mind the sensor’s high sensitivity, adhere to precisely defined values of the measuring range, a maximum of 25Pa, to avoid damage to the sensor itself.

How does it work?

VAV Press Click as its foundation uses the LMIS025B, a low differential pressure sensor that offers a digital output for reading pressure over the specified pressure span from First Sensor (part of TE Connectivity). The innovative LMI technology features superior sensitivity, especially for ultra-low pressures ranging from 0 to 25Pa / 0 to 0.25mbar (0.1 in H2O). It is based on thermal flow measurement of gas through a micro-flow channel integrated within the sensor chip.

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, in addition to the outstanding long-term stability, precision with patented real-time offset compensation, and linearization techniques.

The LMIS025B offers two modes of operation: Continuous mode with a 5ms sampling time which provides a near-continuous stream of pressure data, and low-power mode with a 400μA Standby current which wakes the device from Sleep to serve pressure data “on-demand”. The first measurement in either mode is available after a warm-up and conversion sequence, which takes approximately 25 ms.

VAV Press Click communicates with MCU using the standard I2C 2-Wire interface offering linearized digital output through a 16-bit sigma-delta A/D conversion. Besides, it also allows the choice of the least significant bit of its I2C slave address by positioning the SMD jumper labeled as ADDR SEL to an appropriate position marked as 0 and 1.

This Click board™ can be operated only with a 3.3V logic voltage level. The board must perform appropriate logic voltage level conversion before use with MCUs with different logic levels. However, the Click board™ comes equipped with a library containing functions and an example code that can be used, as a reference, for further development.

Specifications

Pinout diagram

This table shows how the pinout on VAV Press Click corresponds to the pinout on the mikroBUS™ socket (the latter shown in the two middle columns).

Notes	Pin					Pin	Notes
	NC	1	AN	PWM	16	NC
	NC	2	RST	INT	15	NC
	NC	3	CS	RX	14	NC
	NC	4	SCK	TX	13	NC
	NC	5	MISO	SCL	12	SCL	I2C Clock
	NC	6	MOSI	SDA	11	SDA	I2C Data
Power Supply	3.3V	7	3.3V	5V	10	NC
Ground	GND	8	GND	GND	9	GND	Ground

Onboard settings and indicators

VAV Press Click electrical specifications

Software Support

We provide a library for the VAV Press 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 VAV Press Click driver.

Key functions:

• vavpress_cfg_setup – Config Object Initialization function.
• vavpress_init – Initialization function.
• vavpress_default_cfg – Click Default Configuration function.

Examples 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 :

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 Parn", diff_press );
        log_printf( &logger, " Temperature       : %.4f Crn", temperature );
        log_printf( &logger, "--------------------------------rn" );
        Delay_ms( 2000 );
    } 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. The terminal available in all MikroElektronika compilers, or any other terminal application of your choice, can be used to read the message.

mikroSDK

This Click board™ is supported with mikroSDK – MikroElektronika Software Development Kit. To ensure proper operation of mikroSDK compliant Click board™ demo applications, mikroSDK should be downloaded from the LibStock and installed for the compiler you are using.

For more information about mikroSDK, visit the official page.