Bosch DDU 7, Manual

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Display Unit DDU 7 Analog and Frequency Inputs | en 87
Bosch Motorsport Manual 04.02.2019 | V 02 |
Cut-off frequency automatically adjusted to recording rate
Example:
–
100 Hz recording rate (10 ms)
– < 40 Hz pass band (> 99 %)
– 50 Hz stop band (< 1 %)
Linear phase – no signal distortion
0 500 1000 1500 2000 2500 3000
-2
-1.5
-1
-0.5
0
0.5
1
1.5
2
Abtastwerte (roh)
Wert
10000Hz Abtastrate
0 5 10 15 20 25 30
-1.5
-1
-0.5
0
0.5
1
1.5
Abtastwerte (gefiltert)
Wert
100Hz Abtastrate
0 5 10 15 20 25 30
-1.5
-1
-0.5
0
0.5
1
1.5
Abtastwerte (dezimiert)
Wert
100Hz Abtastrate
Sensor signal with noise
Recorded signal 100Hz
(unfiltered)
Recorded signal 100Hz
(filtered)
Latency compensation – no filter delay in recorded data
– Filtering is (smart) averaging over several samples
– Filtered signal is delayed with respect to real time signal
– DDU 7 filters have constant, frequency independent delay
– Delay (e.g. 22 samples at 10 ms) is corrected during recording
– No delay filtered vs. unfiltered in recorded data
– Correction is (of course) not possible for real time data (display, online, PWM out)
– Use filtered data for recording, use unfiltered data for real-time
10.3.6 Configuring a frequency input
This function requires the installation of Software Upgrade 2.
Example: measurement of wheel speed
– Pulse wheel attached to wheel
– Each passing tooth of pulse wheel triggers hall sensor
– Calculation of wheel speed with wheel circumference