Hardware
Copyright © 2015 Coda Octopus Products Ltd
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F180R MOTION Sensor User and Reference Guide
All measurements are made in accordance with the conventions stated in the Reference
Frame Chapter.
3.4.1 IMU Orientation
It is rarely possible to install any system on a vessel so that it is perfectly level and oriented in
exact fore–aft alignment with respect to the vessel's frame. Any misalignment between the
system and the vessel's frame might therefore affect the accuracy of measurements delivered
by the system by applying a permanent offset to them. The standard installation orientation
of the F180R System relative to the vessel is for the connector end plate to point directly aft.
The system should also sit level relative to the mounting surface. This orientation will ensure
the system is installed parallel to the vessel's heading axis.
The F180R System allows you to input measured differences between theF180R System frame
of reference and the vessel frame of reference. If it is not possible to make these
measurements then they can be evaluated after system calibration.
The rotation angles that you require are the differences between the F180R System frame of
reference and the vessel's frame of reference. For simplicity the angles are defined as the
rotations needed to re-align the F180R System with the vessel, and use the following
conventions:
Heading mounting rotation (about z Axis)
alignment of the IMU x-y axis to vessel's fore-
starboard axis. Clockwise rotation is positive (looking
down on the wetpod).
Figure 26: IMU Orientation
Pitch mounting rotation (about y Axis)
alignment of the IMU x-z axis to the vessel's fore-down
axis. Anti clockwise rotation, where the connector
moves to the aft, is positive.
Roll mount rotation (about x Axis)
alignment of the IMU y-z axis to the vessel's starboard-
down axis. Clockwise rotation looking at the connector
is positive.
For ease of use MOTION Control provides visual aid in the Settings Wizard for 90° and 180°
orientations in all directions.
WARNING: When using an other than standard like installation see the graphics in the
wizard for axis alignment changes.
NOTE: Definitions of Heading, Pitch and Roll that are output by the F180R System can
be found in Appendix - Rotation Convention.
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