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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.
Most of
measurements have adc_pp higher than 900, therefore permit choose measured
time from better signal quality.
At first local variables are loaded.
Program continue inside one two flag conditions. Then program test from which axis has
measured sequence know where store results.lower than min update them. that case program exit.10 ADC average function
This function serve only inform about amplitude receiving signal. was created for development version of
anemometer let know little about amplitude affection for computation wind
speed.
Illustration 4. 32th calculation, value shifted down and
adc_pp_aver value printed screen with correspondent axis comment. One them adc_ppx_aver or
adc_ppy_aver variable loaded with its counting index. So
program set flag for another measurement and wind calculation will skipped.
When loop done, program calculate ADC peak peak value.
Program returns adc_pp value and exit continue main loop. flag not wind calculation state,
sequence too weak measured time too low.12: Flowchart ADC peak peak function
4. increase adc_pp_aver
variable actual adc_pp value. adc_pp is
lower than 800, received signal too weak include measured time calculation. Then we
29
.4. Its results
aren’t use for wind wind calculation. When shadowed little bit space between sensors, could see amplitude
value goes down and airspeed goes negative values because delayed response of
comparator
