COURSEMASTER CM80i User guide

COURSEMASTER
AUTOPILOTS
A
ustralia's world leader in autopilot technolo
gy
CM80iSYSTEM MANUAL
04-08

CM80iSYSTEM MANUAL
Your Coursemaster CM80iautopilot
system is engineered for accurate and
reliable steering. But remember that it
cannot keep a lookout.
SAFE NAVIGATION IS ALWAYS YOUR
RESPONSIBILITY.
COURSEMASTER AUTOPILOTS PTY LTD.
2/66 Gibbes Streeet,
CHATSWOOD NSW. AUSTRALIA 2067
ABN 25 001 306 369
Phone [phone]
Fax [phone]
E-mail [email protected]
Website www.coursemaster.com
04-08

Third Edition
The Third Edition of this Manual applies to systems fitted with
Version 1.26 Junction Box software or higher. The dynamic
performance of the autopilot has been optimised for use with a
CM437 Rate Gyro Compass.
Copyright 2003, 2005, 2008. This manual,
the mechanical and electronic design of the
CM80iautopilot system and its associated
software are protected by copyright.
Unauthorised copying may result in
prosecution.

QUICK START
•Press the STANDBY key to turn the system on.
•Hold down the STANDBY and PILOT keys
together to turn the system off.
•Steer to the desired course and press PILOT.
•Use the arrow keys to change course.
•To engage the auto-navigate system, hold the
PILOT key down for two beeps. Press PILOT
once to cancel the auto-navigate mode.
•To select the menu, hold the STANDBY key
down for two beeps. Scroll down with single
presses of the STANDBY key. Hold the
STANDBY key down for two beeps to exit the
menu.

CM80iSYSTEM MANUAL
CONTENTS
QUICK REFERENCE
1. SYSTEM DESCRIPTION
1.1 Introduction to autopilots 1-1
1.1.1 Conventional autopilots 1-1
1.1.2 Steering Control 1-3
1.1.3 The ‘intelligent’ autopilot 1-4
1.1.4 Course holding and turning 1-4
1.1.5 Options 1-5
1.1.4 Working with other Equipment 1-6
1.2 The CM80iSystem 1-7
2. OPERATING INSTRUCTIONS
2.1 The Control Head 2-1
2.2 Getting Started 2-2
2.3 Normal Operation 2-4
Switching on
Switching off
Autopilot
Adjusting the course
Auto-navigate
2.4 The Menu 2-6
2.5 Alarms 2-13

CONTENTS
3. INSTALLATION
Step-by-step Summary 3-1
3.1 Junction Box 3-2
3.2 Control Head 3-5
3.3 Rate Gyro Compass 3-6
3.4 NMEA Interfaces 3-9
3.5 Steering Drive 3-12
4. TROUBLE-SHOOTING
4.1 General 4-1
4.2 Error messages 4-1
4.3 Other faults 4-4
4.4 Fuses 4-5
5. SYSTEM SPECIFICATIONS 5-1
6. MAINTENANCE AND WARRANTY 6-1

QUICK REFERENCE
INSTALLATION
•Mount the Junction Box as described in
Sect 3.1
•Mount the Control Head as described in
Sect 3.2
•Mount the Compass as described in Sect
3.3
•Install the Steering Drive as described in
Sect 3.5.
•Connect optional attachments as
described in Sect 3.4
•Carry out the system set-up as described
in Sect 2.2

THE MENU
CONTROL MODE - NORMAL / ROUGH
RUDDER FACTOR
RATE FACTOR
RATE GYRO OFF / ON
HEADING ADJUST
AUTO COMPASS CALIBRATION
MANUAL COMPASS CALIBRATION
COLD START
RUDDER LIMITS
TURN RATE
HELM ALERT
STEER DRIVE
HEADING SOURCE
NMEA OUTPUT
MAGNETIC VARIATION
TUNE MONITOR OFF/ON
AUTO BALANCE OFF/ON

1 SYSTEM DESCRIPTION
1.1 INTRODUCTION TO AUTOPILOTS
The main function of a marine autopilot is to hold the heading
of a vessel on a reference course which is held in the memory
of the autopilot. When it is operating, the autopilot
continuously compares the vessel’s heading with a reference
course, and if they are different, it applies helm to bring the
vessel back on course. Since there has to be a compromise
between the accuracy of course holding and the activity of the
rudder, the autopilot has controls which are set to strike a
balance between these two factors.
1.1.1 CONVENTIONAL AUTOPILOTS
A conventional autopilot is illustrated schematically in Fig 1.1
RUDDER
STEERING DRIVE
COMPASS
RUDDER STEM
CONTROL
POWER
TRANSDUCER

Figure 1.1 Basic components of a conventional marine
autopilot.
The four basic components are a compass, an electronic
control box, a rudder angle sensor (transducer) and the
steering drive.
A Junction Box, mounted below decks, contains most of the
system electronics and a Control Head, mounted at the
steering station provides the interface with the user.
Modern autopilots perform other functions as well and this
introduction explains how these fit in with the basic function
and how they provide a wider range of options for the user.
When the autopilot is first turned on, it rests in an idle
(STANDBY) state in which it displays the heading, but does
not steer the vessel. It is activated by switching it into the
PILOT state. At the moment this is done, the current heading
is put into memory as the reference course and the autopilot
starts steering to hold the heading on this reference course.
The user can change the reference course at any time and the
heading will swing round to match the new course.
There is another way of setting the reference course. If the
autopilot is connected to a GPS navigation receiver, the
heading is then controlled to place the vessel on a direct track
between the origin waypoint and the next waypoint.

1.1.2 STEERING CONTROL
When the vessel swings off course or the reference course is
changed, the autopilot should apply helm in a way, which
brings the vessel onto course quickly, but without
overshooting the reference course. The correct rudder angle
depends on the amount of the error, the speed of the vessel,
its size, the effectiveness of its rudder and the weather
conditions. This choice is managed by four parameters within
the autopilot, as follows.
Rudder Factor
The sensitivity or Rudder Factor sets how many degrees of
helm are applied for a given course error. A mid-range
Rudder Factor setting applies half a degree of helm for each
degree off course. In large or slow vessels it would be more
and in light, fast boats it may be less. If the rudder factor is
too high, oversteering or ‘snaking’ may occur. Too low a
setting causes understeer and a sluggish response.
Counter Rudder
Counter Rudder, or rate feedback, compensates for turning
inertia and is generally used in vessels above 10 m length.
Near the end of a turn, counter rudder is applied to slow the
turn rate so that the heading settles accurately on the new
reference course. Counter rudder also improves stability in a
following sea.
Sea State

The Sea State control is used to introduce a ‘deadband’ in the
course control, so that rudder activity is reduced when the
vessel rolls and yaws in a heavy sea. Full rudder control is
applied when the vessel yaws off course by more than a
preset amount.
Trim
Vessels often show a steering bias or offset, which can be due
to weather, propeller torque or towing a load off-centre. The
autopilot responds to this by progressively trimming the centre
position of the rudder until the average heading of the vessel
equals the reference course.
1.1.3 THE ‘INTELLIGENT’ AUTOPILOT
An ‘intelligent’ autopilot, such as the CM80i,works on the
same principles as those just described, but with two practical
differences. There is no rudder angle sensor. Instead, the
angle is calculated within the system, using inputs from the
steering drive and the compass. Secondly, some internal
settings in the autopilot adapt themselves automatically to
conditions such as propeller torque and offset effects arising
from the weather and the trim of the vessel.
1.1.4 COURSE HOLDING AND TURNING
The CM80i is mainly intended for light vessels in the 5 - 10 m
range. These have two features that affect course holding
and turning. First, they are more responsive to wind load and
wave effects than heavy vessels and can yaw quickly when hit
by a wind gust, for example. Secondly, they are often used at

speeds above 15 kt and are therefore susceptible to the
southerly/northerly heading error effect.
The autopilot responds quickly to correct heading shifts
caused by wind or waves and a yaw of 3 degrees around the
reference course is typical in choppy and windy conditions.
But when there is a constant weather offset, the automatic
trim acts progressively to apply weather helm and bring the
average heading of the vessel onto the reference course.
This action may take 10 - 15 seconds to complete. The
weather helm effect can be seen particularly during a large
course change. If the conditions are not calm, the wind and
wave load on the vessel will be different at the end of the turn
and the vessel may undershoot or overshoot the new
reference course until the trim adjusts to the new conditions.
The northerly/southerly heading error is a result of the dip
angle of the earth’s magnetic field lines. For vessels travelling
above about 15 kt, it produces northerly course holding errors
in regions north of latitude 30N and southerly errors when
south of latitude 30S. The addition of a Rate Gyro overcomes
this problem, as well as reducing rudder activity in choppy
conditions. We now recommend that the CM437 Rate Gyro
Compass be fitted as the standard compass.
1.1.5 OPTIONS
As an alternative to using the standard rate gyro compass, the
CM80i has an option to use a digital heading input, which
would typically come from a GPS compass. Note that the
course-over-ground data available from GPS navigation
systems does not respond quickly enough to be used as the
primary heading input.

1.1.6 WORKING WITH OTHER EQUIPMENT
The physical and electrical environment in a boat can be
harsh. This autopilot has been engineered with this in mind
and tolerates poorly regulated power supplies, overloaded
steering, radio transmitters, radars and the like. Conversely,
it has also been engineered to operate without causing
interference to radio receivers and other communications
equipment. Coursemaster autopilots carry a CE mark to
indicate compliance with the relevant EMC standards. The
installation sections of this manual have been carefully
developed to minimise problems when the autopilot is in this
environment. Please study and follow them!

1.2 THE CM80iSYSTEM
The core of the CM80i system consists of Control Head,
Junction Box, Rate Gyro Compass and Steering Drive. The
system, together with its optional attachments is illustrated in
Fig 1.2 below.

GPS
NAVIGATION
DIGITAL
HEADING
PLOTTER
RADAR /
STEER
DRIVE
12V
POWER
JUNCTION BOX
CM840
CM80i
CONTROL
HEAD
RATE GYRO COMPASS
CM437
Figure 1.2 The CM80isystem.
CM840 Junction Box
The Junction Box contains the control microcomputer, the
interfaces with other system components and the steering
drive electronics. All system cables are terminated in the
Junction Box. The drive system is robust and is designed to
drive mechanical and hydraulic pump steering systems.

CM80i Control Head
The Controller has four push-buttons to control the system
and displays information on the current operation of the
autopilot.
CM437 Rate Gyro Compass
The CM437 Rate Gyro Compass combines a fluxgate sensor
with a rate gyro.
Steering Drive
The autopilot is intended for hydraulic steering systems, of
which there are a number of options. A suitable drive may
either by supplied by Coursemaster or the autopilot may be
connected to an existing steering drive on the vessel. One of
the recommended pumps, supplied by Coursemaster, is a 0.6
litre/min reversing gear pump.
2 OPERATING INSTRUCTIONS

2.1 THE CONTROL HEAD
The Control Head (Fig 2.1) contains a text display and four
keys. The use of these controls is described in this chapter.
PILOT
STBY
324
PILOT
324
Turn controls/adjust settings
Reference
Course
Mode
Switch on
Standby/Menu select Auto-navigate
Switch off
Heading
Pilot/
Figure 2.1 The Control Head Panel.
2.2 GETTING STARTED
Before operating the autopilot for the first time, it must be
installed and adjusted as described in Chapter 3. (If optional
attachments are being used, these can be fitted after initial
trials of the system.)

To switch on for the first time, press the STANDBY key. The
system enters a set-up mode so that the size of the vessel can
be entered and the steering gear calibrated. The screen
shows the prompt:
COLD START
PRESS STBY
Press STANDBY and the screen reads:
PROCEED >
SKIP <
There are two choices. If you wish to examine some of the
features without carrying out the setup, select SKIP by
pressing the left arrow. This will bypass the setup and let you
scroll through the displays, but there will be no response to
the PILOT key. The system will return to SYSTEM SETUP
the next time it is turned on. To carry out the setup, select
PROCEED by pressing the right arrow.
HULL 10M
USE < >
Set the approximate boat length by using the arrow keys.
These will step up or down in 2 m steps. This is an important

operation and sets the initial tuning of the autopilot to values
which best suit your vessel.
Then press STANDBY again to calibrate the
steering.
20 DG STBD
USE >
Centre the helm. Then watch the steering gear as you press
the right arrow. It should move a few degrees to starboard for
each press of the key. If it moves the wrong way, switch off
the system and reverse the motor lead connections. Continue pressing until 20 deg
helm is applied. If you move too far, use the left arrow to bring it back. Then press STANDBY. The helm
will now pulse back to the centre and the display reads AUTO
RETURN as it moves back. The setup is now complete and
the screen should show its normal display.
If the helm does not return close to centre during this last
operation, there may be air in the hydraulic system and it
should be bled again. Small centring errors will not affect the
operation of the autopilot.
2.3 NORMAL OPERATION
SWITCHING ON