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August 2020 – TD 316 OPERATING MANUAL – Motus Wave Sensor 5729
CHAPTER 7
Use of External Compass
7.1
General information
An important input parameter for calculation of wave parameters is the heading information. If the magnetic distortion at
the location where the sensor is to be installed is too large the heading should be provided by an external compass
placed at an undistorted location, for instance in the mast.
In a system with SmartGuard logger the external compass can be connected directly to the logger or directly to the
wave sensor:
•
External compass connected directly to sensor:
-
The wave sensor has a separate connector for connection of external compass. When properly
configured the sensor will power up the external compass and receive heading information at preset
intervals. Refer to chapter 3.10.5 when controlled via logger or chapter 4.8.5, when used as stand-
alone sensor, for detailed information on how to configure the sensor for connection of external
compass.
-
A special configuration option is provided for the HSC100 compass from Digital Yacht. By using this
option no setup of the compass itself will be required.
-
When an external compass is connected directly to the sensor and the wave sensor is connected to
SmartGuard via AiCaP bus the external compass heading information can be distributed to other
AiCaP sensors in the system.
•
External compass reading input from SmartGuard.
-
In cases where the buoy is equipped with sensors giving heading information directly to the logger
the heading information can be distributed by the logger to other sensors connected to the AiCaP
bus. This feature enables the wave sensor to receive heading information from other connected
sensor in the system via SmartGuard or SeaGuardII.
When using an external compass the orientation angle between the wave sensor and the compass must be taken into
account. This angle must be set in the
Ext Compass Alignment Offset (Deg.M)
- property in the sensor configuration.
By default this is set to zero which means that if the external compass can be aligned to the orientation arrow of the
wave sensor the direction will be correct. A self-leveling crossline laser might be a god tool for aligning the two sensors.
If the installation does not allow for alignment, the angle between the sensors should be measured and the
External
Compass Offset
updated accordingly.
For cable assembly refer to chapter 10.2 in this document.
