ii. Select
Set-up
.
iii. Select
Autopilot Calibration
.
iv. Select
Drive Settings
.
v. Select
Hard Over Time
.
vi. Use the
+10
button (p70) or
ROTARY
control (p70r) to
specify the hard-over time.
STEP
5
Compass linearization
With Evolution autopilot systems, when the EV unit is first
installed and powered-up, its internal compass needs to
compensate for local magnetic variations and the earth’s
magnetic field. This is achieved using an automatic process
known as linearization, which forms an important part of the
autopilot installation, commissioning and set-up process.
Linearization
In Evolution systems, the linearization process is performed
automatically by the EV unit as a background task once the
vessel's speed exceeds 3 knots, and no user intervention is
required. The process will occur during your first voyage with
the autopilot system, and will typically take no more than 30
minutes, but this does vary according to the characteristics of
the vessel, the installation environment of the EV unit, and
the levels of magnetic interference at the time of conducting
the process. Sources of significant magnetic interference may
increase the time required to complete the linearization process.
Examples of such sources include:
• Marine pontoons.
• Metal-hulled vessels.
• Undersea cables.
Note:
You can speed-up the linearization process by
completing a 360 degree turn (at a speed of 3 – 15 knots).
You can also restart the linearization process at any time by
selecting the
Restart Compass
menu item.
Use the compass deviation indicator
The use of the compass deviation indicator on the pilot control
head may be useful in this process, particularly if the EV unit has
been installed in a location on the vessel where the levels of
magnetic interference are too high for the EV unit to compensate
appropriately. If this is the case, the deviation display will indicate
a value of 25 degrees or higher. In this scenario, Raymarine
highly recommends that the EV unit is moved and re-installed in
a location which is subject to less magnetic interference. If “- -”
is displayed as the Deviation value, it means that linearization
has not been successfully completed yet.
Check the compass heading data
As part of the autopilot system commissioning process,
Raymarine recommends that you check the compass heading
value displayed on your autopilot control head or multifunction
display, against a good known heading source on various
headings. This will help you to determine when the EV unit has
completed its linearization process.
Note:
Once the linearization process has completed, it is
possible that the heading value may have a slight offset of 2 to
3 degrees. This is common where installation space is limited,
and the EV unit cannot be properly aligned to the vessel's
longitudinal axis. In this case, it is possible to manually adjust
the compass offset value using the pilot control head or
multifunction display, and fine-tune the heading to an accurate
value.
Note:
Do NOT rely on the heading accuracy until you are
satisfied that compass linearization and alignment is complete.
Accessing the compass deviation indicator
1. Select
MENU
.
2. Select
Set-up
.
3. Select
Diagnostics
.
4. Select
About Pilot
.
The details related to the pilot diagnostics are displayed.
5. Scroll down to the bottom of the list to view the entry for
Deviation
.
Note:
If “- -” is displayed as the Deviation value, it means that
linearization has not been successfully completed yet.
Adjusting the compass offset
With the pilot in Standby:
1. Select
MENU
.
2. Select
Set-up
.
3. Select
Autopilot Calibration
.
4. Select
Vessel Settings
.
5. Select
Compass Offset
.
6. Use the
+/- 10
button (p70) or
ROTARY
control (p70r) to
adjust the compass offset as appropriate.
STEP
6
Compass lock
Once you are satisfied with the compass accuracy, you can lock
the setting to prevent the autopilot system from completing a
further automatic linearization in the future.
This feature is particularly useful for vessels in environments that
are exposed to strong magnetic disturbances on a regular basis
(such as offshore wind farms or very busy rivers, for example).
In these situations it may be desirable to use the Compass lock
feature to disable the continuous linearization process, as the
magnetic interference may build a heading error over time.
Note:
The compass lock may be released at any time, to
allow the compass continuous linearization to restart. This
is particularly useful if planning a long voyage. The earth’s
magnetic field will change significantly from one geographical
location to another, and the compass can continuously
compensate for the changes, ensuring you maintain accurate
heading data throughout the voyage.
4
