Section 7. Installation
250
For the example above, the delay is:
Delay in time = (1 ms) • (4
–
1) / 2 = 1.5 ms
Example:
An accelerometer was tested while mounted on a beam. The test had the
following characteristics:
o
Accelerometer resonant frequency ≈ 36 Hz
o
Measurement period = 2 ms
o
Running average duration = 20 ms (frequency of 50 Hz)
Normalized resonant frequency was calculated as follows:
36 Hz / 50 Hz = 0.72
SIN(0.72π) / (0.72π) = 0.34.
So, the recorded amplitude was about 1/3 of the input-signal amplitude. A
CRBasic program was written with variables
Accel2
and
Accel2RA
. The
raw measurement was stored in
Accel2
.
Accel2RA
held the result of
performing a running average on the
Accel2
. Both values were stored at a
rate of 500 Hz. Figure
Running-Average Signal Attenuation
(p. 251)
shows the
two variables plotted to illustrate the attenuation. The running-average value
has the lower amplitude.
The resultant delay, D
r
, is calculated as follows:
D
r
= (scan rate) • (N–1)/2 = 2 ms (10–1)/2
= 9 ms
D
r
is about 1/3 of the input-signal period.
Содержание CR6 Series
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Страница 76: ...Section 5 Overview 76 FIGURE 20 Half Bridge Wiring Example Wind Vane Potentiometer ...
Страница 80: ...Section 5 Overview 80 FIGURE 23 Pulse Input Wiring Example Anemometer ...
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Страница 251: ...Section 7 Installation 251 FIGURE 46 Running Average Frequency Response FIGURE 47 Running Average Signal Attenuation ...
Страница 454: ...Section 8 Operation 454 FIGURE 104 Narrow Sweep High Noise ...
Страница 459: ...Section 8 Operation 459 FIGURE 106 Vibrating Wire Sensor Calibration Report ...
Страница 535: ...Section 8 Operation 535 8 11 2 Data Display FIGURE 121 CR1000KD Displaying Data ...
Страница 537: ...Section 8 Operation 537 FIGURE 123 CR1000KD Real Time Custom ...
Страница 538: ...Section 8 Operation 538 8 11 2 3 Final Storage Data FIGURE 124 CR1000KD Final Storage Data ...
Страница 539: ...Section 8 Operation 539 8 11 3 Run Stop Program FIGURE 125 CR1000KD Run Stop Program ...
Страница 541: ...Section 8 Operation 541 FIGURE 127 CR1000KD File Edit ...
Страница 542: ...Section 8 Operation 542 8 11 5 PCCard Memory Card Management FIGURE 128 CR1000KD PCCard Memory Card Management ...
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Страница 549: ...Section 9 Maintenance Details 549 FIGURE 133 Separate Back Shell from Module FIGURE 134 Disconnect Battery Connector ...
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Страница 610: ...Section 11 Glossary 610 FIGURE 137 Relationships of Accuracy Precision and Resolution ...
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