CMA3000-A0X Series
Pin #1
Z
X
Y-axis in +1 g
position
Earth’s
gravitation
X
Z
Y-axis in -1 g
position
Pin #1
Figure 9. CMA3000 positions for Y-axis sensitivity measurement.
Sensitivity is calculated by
Equation 3
OutputY −axis@+1g −OutputY −axis@−1g
SensY −axis
=
,
2g
where SensY-axis is sensor’s Y-axis sensitivity in [counts/g], OutputY-axis@+1g sensor’s Y-axis output
reading [counts] in +1 g position and OutputY-axis@-1g is sensor’s Y-axis output reading [counts] in -1 g
position.
5.2.1 Sensitivity calibration error
Sensitivity calibration error is the difference between sensor’s measured sensitivity and the nominal
sensitivity at room temperature conditions. Error is calculated by
Equation 4
SensY −axis − Sens
SensY −axisCalibEr
=
⋅100% ,
Sens
where SensY-axisCalibEr is sensor’s Y-axis sensitivity calibration error in [%], SensY-axis sensor’s Y-axis
sensitivity [counts/g] at room temperature conditions and Sens is sensor’s nominal sensitivity
[counts/g].
5.2.2 Sensitivity temperature error
Sensitivity temperature error is the difference between sensor’s sensitivity at different temperatures
and the calibrated sensitivity. Error is calculated by
Equation 5
SensY −axis@T − SensY −axis@RT
SensY −axisTempEr@T
=
⋅100% ,
SensY −axis@RT
where SensY-axisTempEr@T is sensor’s Y-axis sensitivity temperature error in [%] in temperature T, SensY-
axis@T is sensor’s measured Y-axis sensitivity [counts/g] at temperature T and SensY-axis@RT is sensor’s
measured Y-axis sensitivity [counts/g] at room temperature RT.
5.3 Linearity
The needed accurate input acceleration in linearity characterization is generated using centrifugal
force in centrifuge, see Figure 10. The RPM of the centrifuge is sweeped so that wanted input
acceleration values are applied in parallel to the sensor’s measuring axis.
VTI Technologies Oy
www.vti.fi
PRELIMINARY - Subject to changes
Doc.Nr. 8282100.05
11/ 17
Rev.05
VTI [ VTI TECHNOLOGIES ]
