Simrad IS20 Manual page 64

4. The automatic calibration is completed when the
Heading offset
After compass calibration, the heading should be checked
against a known reference, a compensated compass or a
bearing.
64 | Configuration
Turn rate too high,
turning cw
information window disappears from the display
Range Change per step
-180 - +180
Turn rate too low,
If the compass reading has a fixed
offset, use the Offset parameter to
compensate.
Default value
1
turning cw
Units
0 °