How Autopilots Work
Sitex SP38 Installation and Operation
Document PN
29010101
V2r0
- 1
7
-
Basic Autopilot System
Figure
1
is a block diagram of the major components of an autopilot system.
COMPASS
READS THE VESSEL'S
ACTUAL HEADING AND
SENDS IT TO THE SPU
PROCESSOR (SPU)
CALCULATES THE RUDDER
POSITION NEEDED TO STEER
THE VESSEL ON THE DESIRED
HEADING, AND CONTROLS THE
STEERING SYSTEM
ACCORDINGLY
STEERING SYSTEM (ACTUATOR)
[HYDRAULIC RAM OR ELECTRIC MOTOR
WHICH IS MECHANICALLY CONNECTED
TO THE RUDDER]
MOVES THE RUDDER IN RESPONSE TO
CONTROL SIGNALS FROM THE SPU
RUDDER FOLLOWER UNIT (RFU)
[MECHANICALLY CONNECTED TO RUDDER]
MEASURES RUDDER POSITION AND SENDS
IT TO THE SPU
NAVIGATION DEVICES
[OPTIONAL]
SUPPLY NAVIGATION
INFOMRATION TO THE SPU
IN NMEA 0183 FORMAT
CONTROL HEAD
DISPLAYS STATUS AND HEADING
INFORMATION FROM THE SPU, AND
ALLOWS THE OPERATOR TO INPUT
STEERING COMMANDS & OPERATING
PARAMETERS
Figure 1
– Basic Autopilot System
The Compass indicates the direction in which the boat is pointed, often referred to as the Actual
Heading. Depending on the type of boat and installed equipment, the Compass may be a
magnetic compass, an electronic fluxgate compass, a gyroscopic compass, or a GPS Compass.
•
A reliable compass is absolutely vital to the autopilot; without a trusted compass, the autopilot
has no way of knowing where the boat is, or which way it is headed.
The actual heading is fed electronically from the Compass to the Signal Processor Unit (SPU),
which is the heart of the autopilot. The SPU contains the microcontroller(s), electronic hardware,
and the sophisticated control software necessary to steer the boat on any
desired Heading
.
The Control Head, normally located in the wheelhouse, is the interface between the vessel’s
operator and the autopilot. The Control Head displays information about what the autopilot is
doing, and it has various controls (buttons and/or knobs) that allow you to give commands to the
autopilot.
OR IN NMEA2000
FORMAT
Summary of Contents for SP38 Autopilot
Page 2: ......
Page 14: ...Sitex SP38 Installation and Operation Document PN 29010101 V2r0 13 ...
Page 15: ...Sitex SP38 Installation and Operation Document PN 29010101 V2r0 14 Introduction ...
Page 16: ...Sitex SP38 Installation and Operation Document PN 29010101 V2r0 15 ...
Page 26: ...Sitex SP38 Installation and Operation Document PN 29010101 V2r0 25 ...
Page 35: ...Sitex SP38 Installation and Operation Document PN 29010101 V2r0 34 Installation ...
Page 36: ...Sitex SP38 Installation and Operation Document PN 29010101 V2r0 35 ...
Page 74: ...Sitex SP38 Installation and Operation Document PN 29010101 V2r0 73 ...
Page 108: ...Sitex SP38 Installation and Operation Document PN 29010101 V2r0 107 ...
Page 109: ...Sitex SP38 Installation and Operation Document PN 29010101 V2r0 108 Advanced Operations ...
Page 110: ...Sitex SP38 Installation and Operation Document PN 29010101 V2r0 109 ...
Page 123: ...Sitex SP38 Installation and Operation Document PN 29010101 V2r0 122 Care and Maintenance ...
Page 124: ...Sitex SP38 Installation and Operation Document PN 29010101 V2r0 123 ...
Page 127: ...Sitex SP38 Installation and Operation Document PN 29010101 V2r0 126 Appendices ...
Page 128: ...Sitex SP38 Installation and Operation Document PN 29010101 V2r0 127 ...
Page 156: ...Sitex SP38 Installation and Operation Document PN 29010101 V2r0 155 Warranty ...
Page 157: ...Sitex SP38 Installation and Operation Document PN 29010101 V2r0 156 User Notes and Settings ...
Page 158: ...Sitex SP38 Installation and Operation Document PN 29010101 V2r0 157 ...