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