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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.
first adc_sample function stored captured ADC samples adc_array
field.
Then gpio_post_int gives measured time and the time correct range, set
flag X_WIND_CALC Y_WIND_CALC state. Input arguments are with actual measured time, adc_pp for
time correction based peak peak ADC value received signal. first level
there are conditions. Addresses of
tx_array and ty_array are given count time values first position array and
keep last averages here. Here
starts measurement axis. don’t measure every cycle we
measure when wind speed for axis was updated.
The last what can measured temperature. After that initialization functions are called.
Functions inside third condition serve measure received signal and calculate
wind speed. Then
adc_ppx_aver and adc_ppy_aver are used for averaging actual adc_pp value. For
calculation ADC sequence peak peak value, adc_pp takes place. see adc_pp averaged value from last ADC sequences.3 Main function
Function start with local variable definitions.
Program continues infinite while loop. The
function returns actual adc_pp value. Then temp
variable adjust airspeed constant actual temperature condition. The
temp variable serve for temperature measurement. Here flag variable tested. used capture time from timer,
tx_array and ty_array are used buffer time averages from measurements before.
Program continue with display initialization. When flag doesn’t fulfill any condition,
program waiting interrupt. With 32th calling this function, new wind
speed value calculated.4. first line the display printed
application name. Otherwise set flag measure
again with X_PWM Y_PWM state. It
means that signal was received, it’s triggered timer_post_int function. The last variables are and
serve for counting cycles. Second condition fulfilled after timer interrupt.4. that moment variable equal to
23
. The function called with address first field adc_array. Address and variables let know number order this
function. we
received signal, third condition fulfilled. Then function adc_pp_average called inform
us about adc_pp value.
Forth conditions tests flag measurement results are convenient add actual
measured time wind speed calculation. With first condition pwm_prepare function called. Therefore input argument first field captured ADC sequence.
In adc_peaktopeak function calculated ADC peak peak value stored
sequence. As
input argument are adc_pp variable and addresses adc_ppx_aver, adc_ppy and
i variables
