BSEC2.4.0.0 Heat Profile duration

[Julien1]

Hi,

I have collected data using the BME688 Development Kit with 8 BME688 sensors and then generated an algorithm for BSEC2.4.0.0 using IA Studio 2.0.0

I used the default heat profile HP-354

I can init BSEC Library and load algorithm file without problem but after calling bsec_sensor_control() to retrieve sensor settings, I can see that the duration of each step of heat profile are too short :

duration: 5ms, temp: 320 C
duration: 2ms, temp: 100 C
duration: 10ms, temp: 100 C
duration: 30ms, temp: 100 C
duration: 5ms, temp: 200 C
duration: 5ms, temp: 200 C
duration: 5ms, temp: 200 C
duration: 5ms, temp: 320 C
duration: 5ms, temp: 320 C
duration: 5ms, temp: 320 C
duration total: 77ms

For each Step the Temperature looks correct but the duration is too short, for a total duration of 77m instead of ~10,8s

What am I doing wrong ?

[BSTRobin]

Hi Julien1,

Did you run official example code or the code written by yourself?

[Julien1]

Hi,

I modified the bsec_iot_example code delivered with the BSEC2.4.0.0 release from 23.01.2022

Below are my init and bsec calls functions:

int bme68x_bsec2_lib_intf_init(struct bme68x_dev* bme68x_sensor, struct bme68x_device* bme68x_i2c_dev, store_bsec2_state _st, load_bsec2_state _ld)

{

    st = _st;

    ld = _ld;

    return_values_init ret = {BME68X_OK, BSEC_OK};

    bme68x_sensor->intf_ptr = (void*)bme68x_i2c_dev;

    bme68x_sensor->chip_id = 0x76;

    bme68x_sensor->intf = BME68X_I2C_INTF;

    bme68x_sensor->amb_temp = 25;

    bme68x_sensor->read = bme68x_bsec2_lib_intf_read;

    bme68x_sensor->write = bme68x_bsec2_lib_intf_write;

    bme68x_sensor->delay_us = bme68x_bsec2_lib_intf_delay_usec;

    /* Initialize bme68x API */

    ret.bme68x_status = bme68x_init(bme68x_sensor);

    if (ret.bme68x_status != BME68X_OK)

    {

        return -1;

    }

    /* Initialize BSEC library */

    ret.bsec_status = bsec_init();

    if (ret.bsec_status != BSEC_OK)

    {

        return -1;

    }

    /* Load library config, if available */

    bsec_config_len = config_load(bsec_config, sizeof(bsec_config));

    if (bsec_config_len != 0)

    {      

        ret.bsec_status = bsec_set_configuration(bsec_config, bsec_config_len, work_buffer, sizeof(work_buffer));

        if (ret.bsec_status != BSEC_OK)

        {

            return -1;

        }

    }

    /* Load previous library state, if available */

    bsec_state_len = state_load(bsec_state, sizeof(bsec_state));

    if (bsec_state_len != 0)

    {      

        ret.bsec_status = bsec_set_state(bsec_state, bsec_state_len, work_buffer, sizeof(work_buffer));    

        if (ret.bsec_status != BSEC_OK)

        {

            return -1;

        }

    }

    /* Call to the function which sets the library with subscription information */

    #ifdef GAS_SCAN_MODE

    ret.bsec_status = bme68x_bsec_update_subscription(BSEC_SAMPLE_RATE_SCAN); // SCAN for Gas estimate

    #else

    ret.bsec_status = bme68x_bsec_update_subscription(BSEC_SAMPLE_RATE_LP); // Low Power (or ULP) for IAQ

    #endif

    if (ret.bsec_status != BSEC_OK)

    {

        return -1;

    }

    memset(&sensor_settings, 0, sizeof(sensor_settings));

    opMode = sensor_settings.op_mode;

    sensor_settings.next_call = 0;

    return 0;

}

void handle_bsec_calls(struct bme68x_dev* bme68x_sensor, struct bme68x_data* data, uint32_t save_intvl)

{

    int8_t ret_val;

    bsec_library_return_t bsec_status = BSEC_OK;

    /* get the timestamp in nanoseconds before calling bsec_sensor_control() */

    time_stamp = get_timestamp_us() * 1000;

    printk("time_stamp: %lld, next_call: %lld, diff: %lld\n",

    time_stamp/1000000, sensor_settings.next_call/1000000, (time_stamp - sensor_settings.next_call) / 1000000 );

    if(time_stamp > sensor_settings.next_call)

    {  

        /* Retrieve sensor settings to be used in this time instant by calling bsec_sensor_control */

        bsec_status = bsec_sensor_control(time_stamp, &sensor_settings);

        if (bsec_status != BSEC_OK)

        {

            if (bsec_status < BSEC_OK)

            {

                printf("ERROR: bsec_sensor_control: %d\n", bsec_status);            

            }

            else

            {

                printf("WARNING: bsec_sensor_control: %d\n", bsec_status);

            }

        }

        else

        {

            int dur_tot = 0;

            for (int i = 0; i < sensor_settings.heater_profile_len; i++)

            {

                printk("duration: %dms, temp: %d C\n", sensor_settings.heater_duration_profile[i], sensor_settings.heater_temperature_profile[i]);

                dur_tot += sensor_settings.heater_duration_profile[i];

            }

            printk("duration total: %dms\n", dur_tot);

        }

        switch (sensor_settings.op_mode)

        {

        case BME68X_FORCED_MODE:

            setBme68xConfigForced(&sensor_settings, bme68x_sensor);

            break;

        case BME68X_PARALLEL_MODE:

            if (opMode != sensor_settings.op_mode)

            {

                setBme68xConfigParallel(&sensor_settings, bme68x_sensor);

            }

            break;

        case BME68X_SLEEP_MODE:

            if (opMode != sensor_settings.op_mode)

            {

                ret_val = bme68x_set_op_mode(BME68X_SLEEP_MODE, bme68x_sensor);

                if ((ret_val == BME68X_OK) && (opMode != BME68X_SLEEP_MODE))

                {

                    opMode = BME68X_SLEEP_MODE;

                }

            }

            break;

        }

        if (sensor_settings.trigger_measurement && sensor_settings.op_mode != BME68X_SLEEP_MODE)

        {

            nFields = 0;

            bme68x_get_data(lastOpMode, &sensor_data[0], &nFields, bme68x_sensor);

            iFields = 0;

            if(nFields)

            {

                do

                {

                    nFieldsLeft = getData(data);

                    /* check for valid gas data */

                    if (data->status & BME68X_GASM_VALID_MSK)

                    {

                        if (!processData(time_stamp, data, sensor_settings.process_data))

                        {

                            return;

                        }

                    }

                }while(nFieldsLeft);

            }

        }

        /* Increment sample counter */

        n_samples++;

        /* Retrieve and store state if the passed save_intvl */

        if (n_samples >= save_intvl)

        {

            bsec_status = bsec_get_state(0, bsec_state, sizeof(bsec_state), work_buffer, sizeof(work_buffer), &bsec_state_len);

            if (bsec_status == BSEC_OK)

            {

                state_save(bsec_state, bsec_state_len);

            }

            n_samples = 0;

        }  

    }

}

[Julien1]

Update: 

handle_bsec_calls() is called every ~3 seconds

I get a gas estimate output wit accuracy = 3 every ~150 seconds, is it a normal behavior ?

[Julien1]

Hi,

Could you give me feedback on this ?

How can I verify that the heat profile duration is correct ?