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Kategorie: Diplomové, bakalářské práce |
Tento dokument chci!
Práce popisuje principy a problémy při realizaci ultrazvukového anemometru. Je popsán princip výpočtu rychlosti větru a následné korekce výpočtu. Pro realizaci jsou využity ultrazvukové sensory a microcontrolér ARM Cortex-M3. Práce se zabývá generováním PWM signálu, jeho analogovou filtrací, zesílením a odvysíláním. Na přijímací straně jeto nízkonapěťový zesilovač a komparátor. Vyvíjený kód je popsán pomocí vývojového diagramu.
Second condition fulfilled after timer interrupt. For
calculation ADC sequence peak peak value, adc_pp takes place. Addresses of
tx_array and ty_array are given count time values first position array and
keep last averages here. Address and variables let know number order this
function.
Functions inside third condition serve measure received signal and calculate
wind speed. Input arguments are with actual measured time, adc_pp for
time correction based peak peak ADC value received signal. The
temp variable serve for temperature measurement.
The last what can measured temperature. Therefore input argument first field captured ADC sequence. we
received signal, third condition fulfilled. It
means that signal was received, it’s triggered timer_post_int function.
In adc_peaktopeak function calculated ADC peak peak value stored
sequence. When flag doesn’t fulfill any condition,
program waiting interrupt.
Program continues infinite while loop. used capture time from timer,
tx_array and ty_array are used buffer time averages from measurements before.
Program continue with display initialization.4. first line the display printed
application name.3 Main function
Function start with local variable definitions. Here flag variable tested. After that initialization functions are called. The last variables are and
serve for counting cycles.
Then gpio_post_int gives measured time and the time correct range, set
flag X_WIND_CALC Y_WIND_CALC state. Here
starts measurement axis. With 32th calling this function, new wind
speed value calculated. The function called with address first field adc_array. The
function returns actual adc_pp value. see adc_pp averaged value from last ADC sequences.4. Otherwise set flag measure
again with X_PWM Y_PWM state. As
input argument are adc_pp variable and addresses adc_ppx_aver, adc_ppy and
i variables. first adc_sample function stored captured ADC samples adc_array
field. Then
adc_ppx_aver and adc_ppy_aver are used for averaging actual adc_pp value. that moment variable equal to
23
. don’t measure every cycle we
measure when wind speed for axis was updated. Then function adc_pp_average called inform
us about adc_pp value. first level
there are conditions. With first condition pwm_prepare function called. Then temp
variable adjust airspeed constant actual temperature condition.
Forth conditions tests flag measurement results are convenient add actual
measured time wind speed calculation
