ifm electronic JN2100 v.2.2.0 - Manual (Page 20)

Inclination sensor JN
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8.2 Euler angle (SDO index 2044h = 1)
In this setting the two provided angle values are to be interpreted as Euler angle.
The current sensor orientation is determined by two successive rotations from the
horizontal position.
The "inclination value longitudinal" indicates the angle [°] at which the Z axis of
the sensor is inclined. The "inclination value lateral" corresponds to the angle [°] at
which the sensor was then rotated about the (inclined) Z axis.
Interpretation
The first angle value corresponds to the angle between the gravitation vector and
the sensor's Z axis (slope inclination, gradient angle) whereas the second angle
value indicates the direction in which the slope inclination matches the coordinate
system.
Value range for this option
– Inclination value longitudinal (gradient angle): -90°…+90°
– Inclination value lateral (angle of direction): 0°…360°
Critical point
With a gradient angle of 0° the sensor is in a horizontal position. In this position the
second angle (angle of direction) is useless. In practice, it is to be expected that
the value of the second angle will vary very strongly even if the sensor is virtually
motionless.
8.3 Gimbal angle X (SDO index 2044 = 2)
As with the Euler angle the current orientation of the sensor is described by two
successive rotations from the horizontal position.
But the current orientation now arises from a rotation about the Y axis with the
angle value [°] indicated by the "inclination value longitudinal" as well as from
a rotation which then follows about the (now rotated) X axis with the angle [°]
"inclination value lateral".
Interpretation
If you imagine the sensor as a plane whose body shows in x direction and
whose wings in y direction, the "inclination value longitudinal" corresponds to the
longitudinal inclination of the plane (pitch angle) and the "inclination value lateral"
to the bank angle (roll angle) of the plane.
Value range
– Inclination value longitudinal: -90°…90°
– Inclination value lateral: -180°…180°
Critical point
With a longitudinal inclination of ± 90° ("plane" flies vertically downwards or
upwards) the roll angle makes a rotation about the gravitational axis which cannot