CMA3000-D0X Datasheet, PDF (28/35 Pages) VTI technologies – 3-axis accelerometer

CMA3000-D0X Series
X
Z
Centrifugal
acceleration
for Z-axis
Y
Pin #1
Figure 20. Centrifugal acceleration applied for CMA3000 Z-axis.
Linearity error is the deviation from the best bit straight line. See Figure 21.
Acceleration reading
from CMA3000 [g]
-FS
CMA3000 output
readings
Sensor’s ideal
output
CMA3000 linearity
error in [g] at input
acceleration acc
+FS
acc
Input acceleration [g] (centrifugal
acceleration in parallel to
CMA3000 measuring axis)
Possible offset error is not
included into linearity error
Figure 21. CMA3000’s linearity error at input acceleration acc.
Linearity error is calculated by
Equation 6
LinEr_{Z −axis @ acc}
=
Output_{Z−axis @ acc} − Output_{@ acc}
Sens ⋅ FS
⋅100% ,
where LinEr_Z-axis@acc is sensor’s Z-axis linearity error [%FS] on input acceleration acc, Output_Z-axis@acc
is sensor’s measured Z-axis output [counts] on input acceleration acc, Output_@acc is sensor’s
nominal output [counts] on input acceleration acc, Sens is sensor’s nominal sensitivity [counts/g] and
FS is sensor’s full scale measuring range [g] (for example for CMA3000-D01 with ±2g setting →
FS = 2 g).
Sensor’s ideal output Output_@acc (in Equation 6) is calculated by fitting a straight line to measured
accelerations from –FS to FS.
8.4 Noise
Output noise n_X, n_Y and n_Z in X,Y and Z directions is the measured standard deviation of the output
values when the sensor is in 0 g position at room temperature. Average noise/axis is calculated by
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Rev. 0.12