Raymarine Raydata, Installation And Operating Handbook

Page: 41 / 87

32 RAYDATA Installation and Operation Handbook
There are two methods of updating the speed calibration:
• Automatic calibration. You travel a known distance, and the
RayData calculates and stores the required calibration factor.
• Manual calibration. If you know the calibration factor required for
your vessel, or if you wish to calculate it yourself, you can set the
RayData’s speed calibration value.
In both cases, you need to use the Speed Calibration option from the
Setup pages, as described on the following pages for each method.
Automatic Calibration
To calibrate the speed automatically, run between two points a known
distance apart while the RayData monitors the speed data. You can
perform up to four calibration runs, and the RayData averages the
information to obtain the calibration factor that will be used to correct the
speed data displayed.
Select an easily identifiable measured distance from the chart (between
0.5 and 1.0nm), and carry out the calibration when the tide flow is least.
You should complete a minimum of two runs, one in each direction, to
cancel the tidal effect.
To perform the speed calibration:
1. If one of the Setup pages is not currently displayed, press NAV and
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Ù
together to display the first Setup page.
2. Press SPEED. The Auto Speed Cal page is displayed.
D3043-2
The display shows that the current calibration run number is 1, and
provides a default of 1.00nm for the length of the calibration run.
3. Use the
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key to increase or the
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Ú
key to decrease the value of
the calibration run length, until it matches the length of the
calibration distance you plan to use for this run. You cannot change
the distance units here.