Raytheon NautoPilot NP 5100 Operator's Manual page 122

OPERATION
NautoPilot 5000 Series
"Heading Control" mode is active.
The mode is displayed at the top right corner of the display
(Heading Ctrl.).
Turning the rotary knob will change the preselected heading
value.
Please note: After approx. 15 seconds of inactivity from
rotary knob, the primary heading value is displayed again.
Preselected Heading
125.8
This value is displayed in italic and colors are inverted.
The "SET" LED (near the button) will flash (request to press
the "SET" button).
Pressing the rotary knob transmits the preselected value to
the controller as the new "set heading" (this procedure is
similar to that for a "Direct heading change").
Set Heading
The value is now displayed in non--italics and normal colors.
125.8
The "SET" LED (near the button) will be off.
Please note:
-- It is necessary to observe the Autopilot control function after a heading change.
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4002.DOC010102 Edition: September 2014