NORTHROP GRUMMAN Sperry Marine NAVIGAT X MK 2, Assembly Instructions Manual

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056341 Rev. AA NAVIGAT X Mk 2
Page 5-6 5: Installation
5.4.2 Magnetic Compass Calibration
Ideally, the magnetic heading displayed at the NAVIGAT X Mk 2 would exactly
match the indication of the steering magnetic compass (at a mag. var. of 0.0°).
In practice, deviations will occur between the steering magnetic compass'
heading and the heading data transmitted by an electronic magnetic compass.
The gyrocompass system will automatically correct these deviations if a cali-
bration table has been stored and calibration is activated in the User Setup.
To determine magnetic heading correction values:
Caution
The magnetic compass used as the calibration reference must be properly in-
stalled and adjusted.
The calibration procedure should be carried out in calm seas only.
1) Check that calibration is set to „OFF“ in the User Setup / Mag. C. Cal. Table.
2) Check that the magnetic variation is set to 0.0° in the Manual Settings
menu.
3) Select a manual steering mode.
4) Commence a continuous, slow and steady turn. The vessel must turn
through one full circle at least.
5) While the vessel is turning, compare the indication on the steering mag-
netic compass with the magnetic heading values shown on the gyrocom-
pass' display. For every 10° of steering magnetic compass heading (0°, 10°,
... , 350°), note the corresponding display value.
6) Enter the observed dis-
play values in the mag-
netic compass calibra-
tion table at the back of
this manual.
7) Calculate the required
correction value for
each heading.
The correction value is
the offset which must
be applied to a given
display value in order to
obtain the actual mag-
netic heading.
Example:
The actual magnetic
heading is 0°.
The magnetic heading
display value is 0,8°.
The required correction
value is thus -0,8°.
>F1 GYRO 1 000.4°
MK2 HEADING
F2 MAGN.C. 000.8°
DIFF G1/M 5° ü
magn. compass heading
– mag. hdg. display value
= correction value
0.8˚
0˚
Mag. Compass
Heading
Mag. HDG
Display
(uncalibrated)
Correction
Value
10˚
0.8˚ -0.8˚
0˚
Mag. Compass
Heading
Mag. HDG
Display
(uncalibrated)
Correction
Value
10˚