Simrad NAC-2, NAC-3 Commissioning Manual

NAC-2/NAC-3

Commissioning Manual

ENGLISH

www.bandg.com | www.simrad-yachting.com

Preface

Disclaimer

As Navico is continuously improving this product, we retain the
right to make changes to the product at any time which may not be
reflected in this version of the manual. Please contact your nearest
distributor if you require any further assistance.

It is the owner’s sole responsibility to install and use the equipment
in a manner that will not cause accidents, personal injury or
property damage. The user of this product is solely responsible for
observing safe boating practices.

NAVICO HOLDING AS AND ITS SUBSIDIARIES, BRANCHES AND
AFFILIATES DISCLAIM ALL LIABILITY FOR ANY USE OF THIS PRODUCT
IN A WAY THAT MAY CAUSE ACCIDENTS, DAMAGE OR THAT MAY
VIOLATE THE LAW.

Governing Language: This statement, any instruction manuals, user
guides and other information relating to the product
(Documentation) may be translated to, or has been translated from,
another language (Translation). In the event of any conflict between
any Translation of the Documentation, the English language version
of the Documentation will be the official version of the
Documentation.

This manual represents the product as at the time of printing.
Navico Holding AS and its subsidiaries, branches and affiliates
reserve the right to make changes to specifications without notice.

Trademarks

NMEA® and NMEA 2000® are registered trademarks of the National
Marine Electronics Association.

Copyright

Copyright © 2016 Navico Holding AS.

Warranty

The warranty card is supplied as a separate document.
In case of any queries, refer to the product's web site on

www.simrad-yachting.com or www.bandg.com.

Preface | NAC-2/NAC-3 Commissioning Manual

3

Compliance statements

This equipment complies with:

• CE under EMC directive 2014/30/EU

• The requirements of level 2 devices of Radiocommunications

(Electromagnetic Compatibility) standard

The relevant Declaration of conformity is available in the product's
section on www.simrad-yachting.com or www.bandg.com.

About this manual

The manual assumes that the user has basic knowledge of
navigation, nautical terminology and practices.

Important text that requires special attention from the reader is
emphasized as follows:

Note: Used to draw the reader’s attention to a comment or

Ú

some important information.

Warning: Used when it is necessary to warn

personnel that they should proceed carefully to
prevent risk of injury and/or damage to equipment/
personnel.

Manual version

This manual is written for software version 1.0. The manual is
continually updated to match new software releases. The latest
available manual version can be downloaded from the product site
on www.simrad-yachting.com or www.bandg.com.

4

Preface | NAC-2/NAC-3 Commissioning Manual

Contents

7 Introduction

7 NAC-2 and NAC-3 autopilot computers
7 Autopilot controllers
7 Autopilot computer setup

10 Dockside setup

10 Data source selection
10 Boat characteristics
10 Drive configuration
13 Rudder setup

16 Sea trial

16 Compass setup
17 Transition speed
18 Set rudder zero position
18 Set turn rate
18 Tuning the autopilot

23 User settings

23 Steering profile settings
24 Sailing parameters
25 Turn pattern settings

29 Installation verification

29 Checklist
29 Boat specific settings

32 Maintenance

32 Preventive maintenance
32 Checking the connectors
32 Software update
32 Resetting the autopilot computer

34 Technical specifications

34 NAC-2
35 NAC-3

Contents | NAC-2/NAC-3 Commissioning Manual

5

37 Dimensional drawings

37 NAC-2
37 NAC-3

38 Supported data

38 NMEA 2000 PGNs
41 NMEA 0183 sentences
42 NMEA 2000 PGN description

6

Contents | NAC-2/NAC-3 Commissioning Manual

1

Introduction

NAC-2 and NAC-3 autopilot computers

The NAC-2 and NAC-3 autopilot computers contain the electronics
needed to operate a hydraulic steering pump or mechanical drive
unit, while also interfacing with rudder feedback units and NMEA
2000 devices.

The NAC-2 is designed for boats up to 10 metres (33 feet) in length
and is suitable for low-current pumps, mechanical drive units, or
solenoid valves (8 amps continuous/16 amps peak).

The NAC-3 is designed for boats 10 metres (33 feet) or greater in
length and is rated to operate high-current pumps, mechanical
drive units, and solenoid valves (30 amps continuous/50 amps
peak).

Autopilot controllers

The NAC-2 and NAC-3 autopilot computers can be controlled by
various Simrad and B&G control units. This can be dedicated
autopilot controllers (e.g. AP44), Multifunction displays (MFDs) and
autopilot remote controllers (e.g. OP12) used in combination with
instrument systems, or any combination of the above.

Autopilot functions

NAC-2 and NAC-3 include a large range of functions, but not all
autopilot controllers have access to all options. E.g. autopilot
systems including only an autopilot remote controller (without
display unit) do not have access to turn patterns.

The user interface

The autopilot functions are presented slightly different on the
different displays.

This manual shows screen examples from both MFDs and AP44.

Autopilot computer setup

When the autopilot installation is completed, the setup of the
autopilot computer must be performed. Failure in setting up the
autopilot correctly may prohibit the autopilot from functioning
properly.

Introduction | NAC-2/NAC-3 Commissioning Manual

7

The setup of the autopilot computer is divided in three main steps:

• Installation settings

- Including dockside and seatrial commissioning. See "Dockside
setup" on page 10 and "Sea trial" on page 16

• User adjustment of autopilot settings

- Manual fine-tuning for various operational conditions and user
preferences. See "User settings" on page 23

Note: The Installation settings can only be accessed when the

Ú

autopilot is in Standby mode. Some systems require a
dedicated physical standby key to perform installation
procedures. This key can be a key on the autopilot controller, on
an autopilot remote controller, or it can be a separate standby
key.

Warning: When the autopilot is delivered from

factory and any time after an autopilot reset has been
performed, the installation settings are all reset to
factory preset (default) values. A notification will be
displayed, and a complete setup has to be made.
Failure to do so correctly may prohibit the autopilot
from functioning properly!

8

Introduction | NAC-2/NAC-3 Commissioning Manual

Installation setup workflow

Con gure boat

settings

Drive

con guration

Check rudder

feedback source

selection

Rudder feedback

calibration

Rudder test

Select data

sources

Set transition

speed

Set turn rate low

speed

Tune steering

parameters low

speed

Calibrate compass

Set rudder zero

Power up

Operational

autopilot system

Set turn rate high

speed

Tune steering

Dockside Sea trial

Introduction | NAC-2/NAC-3 Commissioning Manual

9

2

Dockside setup

Data source selection

Before commencing with autopilot computer setup the data
sources must be available and configured.

Data sources selection is required on initial start-up of the system, if
any part of the network has been changed or replaced, or if an
alternative source is made available for a given data type and this
source has not been selected automatically.

You can let the system automatically select your sources, or set up
each source manually. Refer to documentation for the autopilot
controller or for the display unit for details about how to perform
the data source selection.

Boat characteristics

Boat type

Affects steering parameters as well as available autopilot features.
The following options are available:

• Sail

• Displacement

• Planing

10

Note: If the boat type is set to Sail, Virtual Rudder Feedback is

Ú

not available.

Boat length

Used by the autopilot system to calculate steering parameters.

Cruising speed

Used if no speed info is available. It is used by the autopilot system
to calculate steering parameters.

Drive configuration

The drive configuration controls how the autopilot computer
operates the steering system.

Refer to your drive unit documentation for relevant specifications.

Dockside setup | NAC-2/NAC-3 Commissioning Manual

Control method

Used for setting the appropriate control ouput for your drive.
The following options are available:

• Solenoid

For on/off steering of hydraulic valves. Gives fixed rudder speed.

• Reversible motor

For variable speed pumps/drives.

Drive voltage

Nominal drive voltage specified for your drive unit.

• Options: 12 V and 24 V.

Note: 24 V output is only available with 24 V supply.

Ú

The setting must match the spec of the solenoids/pump/motor.

Warning: Selection of improper voltage level for your

drive unit may damage both the drive unit and the
autopilot computer even if the protection circuits are
activated.

Drive engage

Defines how the Engage output is used.
The following options are available:

• Clutch

If your drive unit/motor/pump needs clutch to engage the
actuator, it shall be connected to the "engage" output. Configure
the "Drive engage" as clutch. The clutch will be activated when
autopilot computer is controlling the rudder. In standby, the
clutch is released to allow manual steering. Check specification of
your drive unit to determine whether clutch is required.

• Auto

Output activated when autopilot computer is in Auto, NoDrift or
Navigation modes. For manual rudder control (Standby, NFU and
FU) the output is not activated. Typically used to switch between
two rudder speeds on a continuous running pump, used when

Dockside setup | NAC-2/NAC-3 Commissioning Manual

11

different rudder speeds are required for automatic and Follow­up/Non-Follow-up steering.

Minimum rudder

Some boats may have a tendency to not respond to small rudder
commands around the “course keeping” position because of a small
rudder, whirls/disturbance of the water-stream passing the rudder,
or it is a single nozzle water jet boat. By increasing the Minimum
rudder parameter you may improve the course keeping
performance on some boats. However, this will increase the rudder
activity.

Note: Only set a value for minimum rudder if it proves to give a

Ú

better course keeping performance in calm sea. It should be set
after the autopilot steering parameters have been optimised/
tuned.

Rudder deadband

Prevents the rudder from hunting induced by mechanical play in
the steering gear or rudder.

The following options are available

• Auto

(Recommended).
The rudder deadband is adaptive and is continuously operative. It
will also optimize the deadband to the pressure on the rudder

12

• Manual

If the Auto setting doesn’t perform properly due to extreme
rudder speed and/or overshoot, it can be adjusted manually. Can
also be used to reduce the rudder activity. Rudder commands
smaller than the size of the dead band will be ignored

Find the lowest possible value that will prevent the rudder from
continuous hunting. A wide deadband will cause inaccurate
steering. It is recommended to check rudder stability in AUTO mode
at cruising speed to get pressure on the rudder. (Slight hunting
observed dockside may disappear at cruising speed.)

Dockside setup | NAC-2/NAC-3 Commissioning Manual

Rudder setup

Warning: During the rudder calibration and test the

autopilot computer issues a series of rudder
commands. Stand clear of the helm and do not
attempt to take manual control of the rudder during
this test!

Rudder source

The correct rudder source has to be selected before the rudder
feedback calibration can be performed.

Rudder source selection, MFDs

Dockside setup | NAC-2/NAC-3 Commissioning Manual

13

Rudder source selection, AP44

Note: Virtual Rudder Feedback (VRF) should only be used if no

Ú

rudder feedback is available. Installing a feedback unit will
enhance the performance of an autopilot and provide an
accurate rudder angle indicator on the autopilot display.

Note: VRF is not available if boat type is set to Sail.

Ú

Rudder feedback calibration

Note: Only available if you have a rudder feedback unit installed

Ú

and selected as rudder source.

The rudder feedback calibration determines the rudder feedback's
direction.

• Follow the on-screen guided steps until the rudder calibration is

completed.

Rudder test

This rudder test verifies the drive direction. It detects minimum
power to drive the rudder and reduces the rudder speed if it
exceeds the maximum preferred speed for autopilot operation.

Note: If the boat uses power assisted steering, it is important

Ú

that the engine or electric motor used to enable the power
assist steering is turned on prior to this test.

14

• Run the rudder test as described in the on-screen instructions

- Rudder should make a small movement within 10 seconds,
then follow up with travelling both directions

Dockside setup | NAC-2/NAC-3 Commissioning Manual

Failure to complete test will result in an alarm.

VRF calibration

Note: Only available if the rudder source is set to a virtual

Ú

rudder feedback.

VRF calibration determines the direction of rudder movement, the
minimum output required to move the rudder and the voltage to
rudder speed ratio.

To perform the VRF calibration you must be able to view the
movement of the rudder.

• Follow the on-screen guided steps until the VRF calibration is

completed.

Dockside setup | NAC-2/NAC-3 Commissioning Manual

15

3

Sea trial

A seatrial can only be performed after the dockside settings are
completed.

Note: The seatrial must always be performed in calm

Ú

conditions, in open waters and at a safe distance from other
traffic!

Compass setup

To achieve the best possible performance, the compass should be
calibrated, and any offsets should be compensated for.

The setup needs to be done from an appropriate display unit.
Depending on the unit, access to the compass setup is available
from the compass’s device dialog, or from a dedicated Calibration
option in the unit’s Settings menu.

16

Device dialog, MFDs

Sea trial | NAC-2/NAC-3 Commissioning Manual

Calibration option, AP44

Note: The setup of the compass should be done in calm sea

Ú

conditions and with minimal wind and current to obtain good
results. Ensure that there is enough open water around the
vessel to make a full turn.

Refer to your heading sensor's documentation for further details for
your unit.

Transition speed

The transition speed is the speed at which the system automatically
changes between Low speed and High speed steering profiles.

The steering profiles are used to accommodate the boats' tendency
to exhibit different steering characteristics at different speeds. You
may also have different preferences about the steering performance
of your boat required at low and high speeds.

On power boats it is recommended that you set a value that
represents the speed where the boat's steering characteristics
change. For instance the planing threshold (recommended), or at
the speed you want the autopilot to change behavior.

There is a 2 knots hysteresis to prevent oscillation of high/low
settings when the vessel is travelling at or near the transition speed.

Example
The transition speed is set to 9 knots.

• The system changes from Low profile to High profile when the

speed increases to 10 knots (= Transition speed plus 1 knot)

• The system changes from High profile to Low profile when the

speed decreases to 8 knots (= Transition speed minus 1 knot)

Sea trial | NAC-2/NAC-3 Commissioning Manual

17

The active profile ('Low' or 'High') is shown in the autopilot page
(e.g. AP44) and in the autopilot pop-up (MFDs):

AP44 page MFD Autopilot pop-up

Set rudder zero position

Used to correct the rudder zero position found during dockside
commissioning if the boat needs a small rudder offset in order to
steer straight.

Note: Setting rudder zero position should always be done in

Ú

calm conditions, where steering is not affected by wind and/or
current.

• Bring the rudder to the position where the boat steers straight,

then activate the Set rudder zero option to save the rudder
zero parameter.

Note: On dual engine boats, verify that the engine RPM is equal

Ú

on both engines so that the thrust from both propellers is
equal. Otherwise, the zero rudder position might be set wrong.

18

Set turn rate

Used for setting the preferred turn rate of the boat.

• Bring the boat into a turn with the preferred safe and

comfortable turn rate, then activate the Set turn rate option to
save the turn rate parameters.

Note: The captured turn rate will be stored in the active

Ú

steering profile. This setting must therefore be repeated for
each steering profile.

Tuning the autopilot

Note: Tuning of the autopilot must be done separately for low

Ú

and high speed profiles.

Sea trial | NAC-2/NAC-3 Commissioning Manual

Both Autotune and manual tuning should be performed in
calm or moderate sea conditions.

Providing you have entered correct vessel type, length and cruising
speed, you may not have to perform further manual or automatic
tuning.

Proceed as follows to verify satisfactorily steering:

1. Stabilize the vessel on a heading, and then select AUTO mode

2. Observe course keeping and rudder commands

- The autopilot should keep the vessel on the set heading
within an average of +/-1 degree, providing calm sea and
wind

3. Make some small and bigger heading changes to port and

starboard and observe how the vessel settles on the new
heading

- The vessel should have a minimum of overshoot. See "Rudder
gain" on page 21 and "Counter rudder" on page 21.

If the autopilot is not keeping the heading satisfactorily or not
making the turns satisfactorily, you may now either try the Autotune
function or go directly to manual tuning.

Note: If the vessel is more than approximately 30 m/100 ft or

Ú

has a very high cruising speed it may be unpractical to perform
Autotune. It is then suggested to proceed with manual tuning.

Autotuning

When performing an autotune, the vessel will automatically be
taken through a number of S-turns. Based on the vessel behavior,
the autopilot will automatically set the most important steering
parameters (Rudder gain and Counter rudder).

• Stabilize the vessel on a heading and set the speed as close to

cruising speed as possible, then activate the Autotune function.

- The autopilot will now switch to AUTO mode and take control
of the vessel.

Note: Autotuning can be stopped at any time by pressing the

Ú

STBY key on the autopilot controller.

The autotuning takes approximately 3 minutes to complete. When
completed the autopilot automatically switches to Standby mode,
and the rudder must be controlled manually.

Sea trial | NAC-2/NAC-3 Commissioning Manual

19

Note: All parameters that are set during autotuning can be

Ú

manually adjusted. For optimal steering performance it is
recommended to manually adjust the steering parameters after
running the autotune.

Manual tuning

Rudder gain and Counter rudder can be manually adjusted.

• Stabilize the vessel on a heading and set the speed in the middle

of the profile range (well clear of the transition speed) to avoid
profile switching during tuning. Then activate the Rudder gain
option. Adjust the value according to the descriptions below.

• If required, adjust slightly the Counter rudder option.

20

Tuning parameters, MFDs

Sea trial | NAC-2/NAC-3 Commissioning Manual

Tuning parameters, AP44

A

B

Rudder gain

This parameter determines the ratio between commanded rudder
and the heading error. The higher rudder gain value the more
rudder is applied. If the value is too small it will take a long time to
compensate for a heading error, and the autopilot will fail to keep a
steady course. If the value is set too high the overshoot will increase
and the steering will be unstable.

A The value is set too high. Steering becomes unstable and

often the overshoot will increase

B The value is set too low. It will take a long time to

compensate for a heading error, and the autopilot will fail to
keep a steady course

Counter rudder

Counter rudder is the amount of counteracting (opposite) rudder
applied to stop the turn at the end of a major course change. The
settings depend on vessel’s characteristics, inertia, hull shape and
rudder efficiency.

Sea trial | NAC-2/NAC-3 Commissioning Manual

21

• If the vessel has good dynamic stability, a relatively small value

A B C

will be sufficient

• An unstable vessel will require high value

• The greater the vessel’s inertia, the greater value will be required

Increasing counter rudder value may result in some higher rudder
activity also when steering a straight course, particularly in high
waves.

The best way of checking the value of the Counter rudder setting is
when making turns. The figures illustrate the effects of various
Counter Rudder settings.

A Counter rudder value too low; overshoot response
B Counter rudder value is too high; sluggish and creeping

response

C Correct setting of Counter rudder; ideal response

Perform various course changes and observe how the boat settles
on the new heading. Start with small changes, 10-20 degrees, and
proceed with bigger changes, 60-90 degrees. Adjust Counter rudder
value to obtain best possible response as in illustration C.

Note: As many boats turns differently to port versus starboard

Ú

(due to propeller rotation direction), do the course changes in
both directions. You may end up with a compromise setting of
Counter rudder that gives a little overshoot to one side and a
bit creeping response to the other.

22

Sea trial | NAC-2/NAC-3 Commissioning Manual

4

User settings

The user settings can be configured differently between the
different profiles, depending on boat steering characteristics and
user preferences.

Steering profile settings

The NAC-2 and NAC-3 include two steering profiles (High and Low),
used for high and low boat speed.

The initial parameters are automatically assigned when you select
your vessel type. During the seatrial the parameters will be tuned for
optimized steering performance. See "Tuning the autopilot" on page 18.

The options listed in the next pages are available for both High and
Low speed profiles.

For Rudder gain and Counter rudder, see "Rudder gain" on page 21 and
"Counter rudder" on page 21.

Turn rate

Used for manually setting the turn rate defined during seatrials (Set
turn rate option).

Autotrim

Controls how fast the autopilot will apply rudder to compensate for
a constant heading offset, e.g. when external forces such as wind or
current affects the heading. Lower autotrim will give faster
elimination of a constant heading offset

Note: In VRF mode this parameter controls the time constant of

Ú

the rudder estimate. A lower value makes the rudder estimate
faster, i.e. that it will more quickly catch up with the boat's
movements.

Init rudder

Defines how the system moves the rudder when switching from
power steering to an automatic mode.

The following options are available:

• Center

Moves the rudder to zero position

User settings | NAC-2/NAC-3 Commissioning Manual

23

• Actual

Maintains the rudder angle, and assumes that the current rudder
angle is the trim required to maintain a steady heading.

Rudder limit

Determines the dynamic range of the rudder before its movement
is restricted and alarm is triggered. Typical usage is to limit the
amount of rudder action caused by yawing in following sea.

Note: Rudder limit is not a hard limitation of the rudder range,

Ú

only around the current setpoint.

This Rudder limit does not affect Non-Follow-up or Follow Up
steering.

Off heading limit angle

Sets the limit for the off heading alarm.
When the alarm option is activated an alarm occurs when the actual

heading deviates from the set heading more than the selected limit.

Track response

Defines how aggressively the autopilot should steer towards the
active route's leg.

24

Track approach angle

This setting is a limit to prevent approaching the track too steeply.
Approaching the track at shallower angles is permitted depending
on the cross track distance (XTD) and track response setting.

This setting is used both when you start navigating and whenever
the autopilot is working the boat towards the route.

Course change confirm angle

Defines the limit for automatic course change to next waypoint in a
route when the autopilot is following a route (NAV mode).

If the course change is greater than this set limit, you are prompted
to verify that the upcoming course change is acceptable.

Sailing parameters

Note: Only available if the boat type is set to SAIL.

Ú

User settings | NAC-2/NAC-3 Commissioning Manual

Wind mode

Select what wind angle the autopilot will steer towards.
The following options are available:

• Auto

If True Wind Angle (TWA) is <70º: Wind mode will steer towards
Apparant Wind Angle (AWA)
If TWA is ≥70º: Wind mode will steer towards TWA

• Apparent

Steers towards AWA

• True

Steers towards TWA

Tack time

Controls how fast the autopilot tacks in wind mode.

Tack angle

Controls the angle that the boat will tack to in AUTO mode.

Manual speed

If neither boat speed nor SOG data are available and/or deemed
unreliable, a manual value for speed can be entered and used by
the autopilot to aid steering calculations.

Turn pattern settings

The autopilot computer supports a number of automatic turn
steering features when the autopilot is in AUTO mode.

Note: Turn pattern steering is not available if the boat type is

Ú

set to Sail.

All turn patters, except the U-turn, have associated turn pattern
settings. Depending on the autopilot controller these turn pattern
settings can be adjusted before you start the turn or during the turn.

User settings | NAC-2/NAC-3 Commissioning Manual

25

Turn pattern settings, MFD

Turn pattern settings, AP44

Note: Not all autopilot controllers include turn pattern steering.

Ú

Refer to your autopilot controller for more information.

C-turn (Continuous turn)

Steers the vessel in a circle.

• Turn variable:

- Rate of turn. Increasing the value makes the vessel turn a
smaller circle.

26

U-turn

Changes the current set heading to be 180° in the opposite
direction.

User settings | NAC-2/NAC-3 Commissioning Manual

Spiral turn

B A

D

C

Makes the vessel turn in a spiral with a decreasing or increasing
radius.

• Turn variables:

- Initial radius

- Change/turn. If this value is set to zero, the boat will turn in a
circle. Negative values indicate decreasing radius while positive
values indicate increasing radius.

Zigzag turn

Steers the vessel in a zigzag pattern.

• Turn variables:

- Course change (A)

- Leg distance (B)

Square turn

Makes the vessel automatically turn 90° after having travelled a
defined leg distance.

• Turn variable:

- Leg distance

Lazy-S turn

Makes the vessel yaw around the main heading.

• Turn variables:

- Course change (C)

- Turn radius (D)

Depth contour tracking (DCT)

Makes the autopilot follow a depth contour.

User settings | NAC-2/NAC-3 Commissioning Manual

27

Note: DCT turn pattern is only available if the system has a valid

Ú

depth input.

• Turn variables:

- Depth gain. This parameter determines the ratio between
commanded rudder and the deviation from the selected depth
contour. The higher depth gain value the more rudder is
applied. If the value is too small it will take a long time to
compensate for drifting off the set depth contour, and the
autopilot will fail to keep the boat on the selected depth. If the
value is set too high the overshoot will increase and the
steering will be unstable.

- CCA. The CCA is an angle that is added to or subtracted from
the set course. With this parameter you can make the boat yaw
around the reference depth with lazy-s movements. The larger
the CCA the bigger yawing will be allowed. If the CCA is set to
zero there is no S-ing.

- Ref. depth. This is the reference depth for the DCT function.
When DCT is initiated the autopilot reads the current depth
and set this as the reference depth. The reference depth can be
changed when the function is running.

Note: If depth data is lost during DCT the autopilot will

Ú

automatically switch to AUTO mode.
It is recommended to turn ON the AP Depth Data Missing alarm
when using DCT. When this alarm is activated an alarm will be
raised if the depth data is lost during DCT.

28

User settings | NAC-2/NAC-3 Commissioning Manual

5

Installation verification

When all units in the autopilot system are installed, external
equipment connected and the software configured according to
the previous chapters, the installation should be verified according
to the checklist. The boat specific settings should be noted down in
the relevant tables included this chapter.

Checklist

Description Reference

Units mounted and secured
according to instructions

Network powered and
terminated according to
instructions

Sources selected

Vessel configured "Boat characteristics" on page 10
Drive units configured and

calibrated
Compass calibrated "Compass setup" on page 16
Seatrial completed (manual or

autotune)

Installation instructions for the
units

Wiring instructions for the units

Autopilot control unit
documentation

"Drive configuration" on page 10

"Sea trial" on page 16

Boat specific settings

Boat

Settings

Boat type
Boat length
Cruising speed
Transition sped

Installation verification | NAC-2/NAC-3 Commissioning Manual

29

Drives

Settings

Drive type
Drive control method
Nominal drive voltage
Drive engage
Minimum rudder
Rudder deadband
Manual deadband
Minimum output
Maximum output

Sailing parameters

Settings

Wind mode
Tack time
Tack angle
Manual speed

30

Steering profiles

Settings Low Speed High Speed

Turn Rate
Rudder gain
Counter rudder
Autotrim
Init rudder
Rudder limit

Installation verification | NAC-2/NAC-3 Commissioning Manual

Settings Low Speed High Speed

Off heading limit
Track response
Track approach

angle
Course change

confirm angle

Turn Pattern settings

Settings

Continuous

Rate of turn

Spiral

Initial radius

Change/turn

Zigzag

Course change

Leg distance

Square

Leg distance

Lazy-S

Course change

Turn radius

Depth contour

Depth gain

CCA

Installation verification | NAC-2/NAC-3 Commissioning Manual

31

6

Maintenance

Preventive maintenance

The unit does not contain any field serviceable components.
Therefore, the operator is required to perform only a very limited
amount of preventative maintenance.

Checking the connectors

The connectors should be checked by visual inspection only.
Push the connector plugs into the connector. If the connector plugs

are equipped with a lock, ensure that it is in the correct position.

Software update

You can update the software for the autopilot computer from a
display unit connected to the network.

You can check the autopilot computer's software version from the
display unit's Device list.

The latest software is available for download from the product
website on www.simrad-yachting and www.bandg.com.

Resetting the autopilot computer

You can reset the autopilot to factory default settings.

32

Reset autopilot computer, MFDs

Maintenance | NAC-2/NAC-3 Commissioning Manual

Reset autopilot computer, AP44

The first time the autopilot computer is started after reset, it will run
through the automatic setup-procedure.

Note: Unless you need to clear all values set during the

Ú

installation set-up procedure, you should not perform a reset of
the autopilot computer.

Maintenance | NAC-2/NAC-3 Commissioning Manual

33

Technical specifications

NAC-2

7

Approvals

Compliance EMC directive 2014/30/EU

Electrical

Supply voltage 9-31.2 V DC

Power consumption - Max 500 W

Power consumption - Typical As required to drive rudder

actuator. See pump/motor
power ratings

Recommended fuse rating 20 A

Environmental

Operating temperature -25°C to +55°C (-13°F to 131°F)

Storage temperature -30°C to +70°C (-22°F to 158°F)

Waterproof rating IPx5

Humidity 100%

Shock and vibration Acc to EN60945

Connectivity

NMEA 2000 1 Micro-C port, 1 LEN

Drive 12/24 V DC, min 10 mA, max 3 A

Rudder Feedback Variable voltage/resistive 0‐5 V
NMEA 2000 PGNs See "NMEA 2000 PGNs" on page 38

Physical

Dimensions See "NAC-2" on page 37

Weight 0.6 kg (1.3 lbs)

Compass Safe Distance 500 mm (20 inches)

Warranty 2 years

34

Technical specifications | NAC-2/NAC-3 Commissioning Manual

NAC-3

Approvals

Compliance EMC directive 2014/30/EU

Electrical

Supply voltage 12/24 V DC +/- 10-30%

Power consumption - Max 750 W

Power consumption - Typical As required to drive rudder

actuator. See pump/motor
power ratings

Recommended fuse rating 30 A

Environmental

Operating temperature -25°C - +55°C (-13°F - 131°F)

Storage temperature -30° - +70°C (-22°F - 158°F)

Waterproof rating IPx5

Humidity 100%

Shock and vibration Acc to EN60945

Connectivity

NMEA 2000 1 Micro-C port, 1 LEN
NMEA 0183 1 port IN/OUT. 4.8, 9.6,

19.2 & 38.4 kbaud

Drive • Reversible motor control

of rudder.
Max continuous load 30
A, peak 50 A for 1s

or

• On/off

solenoid control of rudder.
12/24 V DC,
common, load range 10
mA to 10 A, off current <1 mA

Engage Output for bypass/clutch. 12/24

V DC, min 10 mA, max 3 A

Technical specifications | NAC-2/NAC-3 Commissioning Manual

35

Rudder Rudder angle, frequency input.

15 V, 1.4 to 5 kHz, resol. 20 Hz/°

Remote • Input: External open/

close contact for remote
controller

• Output: High/Low mode

indicator signal

Mode External open/close

or pulse contact for autopilot
disengage

Alarm External alarm output for

buzzer/relay. Max 100 mA,
voltage level as local supply

Physical

Dimensions See "NAC-3" on page 37

Weight 0.7 kg (1.6 lbs)

Compass Safe Distance 500 mm (20 inches)

Warranty 2 years

36

Technical specifications | NAC-2/NAC-3 Commissioning Manual

204.0 mm (8.1”)

183.0 mm (7.2”)

57.0 mm (2.2”)

180.0 mm (7.1”)

190.0 mm (7.5”)

169.0 mm (6.63”)

91.0 mm (3.6”)

211.0 mm (8.31”)

195.0 mm (7.68”)

65.5 mm (2.58”)

92.0 mm (3.62”)

196.0 mm (7.72”)

8

Dimensional drawings

NAC-2

NAC-3

Dimensional drawings | NAC-2/NAC-3 Commissioning Manual

37

Supported data

NMEA 2000 PGNs

9

NAC-2

• MD: Main Device

• RF: Rudder Feedback

• VRF: Virtual Rudder Feedback

MD RF VRF

TX RX TX RX TX RX

59392 x x x x x x
59904 x x x x x x
60160 x x x x x x
60416 x x x x x x
60928 x x x x x x
65240 x x x
65305 x x
65323 x x
65341 x
65342 x x
126208 x x x x x x
126996 x x x x
127237 x x
127245 x x x x
127250 x
127251 x
127257 x
127258 x
128259 x
128267 x
129025 x

38

Supported data | NAC-2/NAC-3 Commissioning Manual

MD RF VRF

TX RX TX RX TX RX

129026 x
129029 x
129283 x
129284 x
130306 x
130577 x
130821 x
130840 x x
130845 x x x x
130846 x x x x
130850 x x x x
130851 x x x x
130856 x x
130860 x

Supported data | NAC-2/NAC-3 Commissioning Manual

39

NAC-3

• MD: Main Device

• RF: Rudder Feedback

• VRF: Virtual Rudder Feedback

• NM: NMEA 0183

• CD: Control Device

MD RF VRF NM CD

TX RX TX RX TX RX TX RX TX RX

59392 x x x x x x x x x x
59904 x x x x x x x x x x
60160 x x x x x x x x x x
60416 x x x x x x x x x x
60928 x x x x x x x x x x
65240 x x x x x
65305 x x x
65323 x x
65341 x
65342 x x
126208 x x x x x x x x x x
126996 x x x x x x
127237 x x x
127245 x x x x x x
127250 x x
127251 x x
127257 x x
127258 x x
128259 x x
128267 x x
129025 x x
129026 x x
129029 x x

40

Supported data | NAC-2/NAC-3 Commissioning Manual

MD RF VRF NM CD

TX RX TX RX TX RX TX RX TX RX

129283 x x
129284 x x
130306 x x
130577 x
130821 x
130840 x x
130845 x x x x x x
130846 x x x x x x
130850 x x x x x
130851 x x x x x
130856 x x
130860 x

NMEA 0183 sentences

In Out NMEA 2000 PGN

AAM x 129284
ACK x 130850

129283

APB x

BOD x 129284
BWC x 129284
DPT x 128267

GGA x

GLL x

HDG x 10* 127250

Supported data | NAC-2/NAC-3 Commissioning Manual

129284
129285

129025
129029

129025
129029

41

In Out NMEA 2000 PGN

HDT x 10** 127250
HSC x 127237

129025

RMA x

RMB x

RMC x

ROT x 127251
RSA 5 127245
THS x 127250
VBW x 128259

VHW x

VLW x 129026
VTG x 129026
ZDA x 129033

129026
127258

129283
129284

127258
129025
129026
129033

127250
128259

42

* When magnetic heading source.
** When true heading source.

NMEA 2000 PGN description

59392 ISO Acknowledgement
59904 ISO Request
60160 ISO Transport protocol, Data transfer
60416 ISO Transport protocol, Connection management, RTS

group function
60928 ISO Address claim
65240 ISO Commanded address

Supported data | NAC-2/NAC-3 Commissioning Manual

126208 ISO Command group function
126996 Product information
127237 Heading/Track control
127245 Rudder
127250 Vessel heading
127251 Rate of turn
127257 Attitude
127258 Magnetic variation
128259 Speed, Water referenced
128267 Water depth
129025 Position, Rapid update
129026 COG & SOG, Rapid update
129029 GNSS Position data
129283 Cross Track Error
129284 Navigation data
129283 Cross Track Error
129284 Navigation data
130306 Wind data
130577 Direction data

Supported data | NAC-2/NAC-3 Commissioning Manual

43

44

Supported data | NAC-2/NAC-3 Commissioning Manual

Index

A

About

NAC-2 and NAC-3 7
User interface 7

Autopilot

Autotuning 19
Controllers 7
Functions 7
Manual tuning 20
Reset 32
Setup 7
Tuning 18

B

Boat

Cruising speed 10
Length 10
Transition speed 17
turn rate 18
Type 10

C

Characteristics

Boat 10

Checklist

Boat characteristic
settings 29
Boat specific settings 29
Description

Reference 29
Drive Settings 30
Installation verification 29
Sailing parameters 30
Steering profile settings 30
Turn pattern settings 31

Commissioning

Sea Trial 16

Compliance

Compatibility standard 4

D

Data source selection 10
Drawings

NAC-2 Dimensions 37
NAC-3 dimensions 37

Drive

Configuration 10
Engage, Clutch, Auto 11
Settings, Solenoid,
Reversible motor 11
Voltage 11

F

Factory default settings 32

I

Installation setup workflow 9

M

Manual

About 4
Software, Version,
download 4

N

NMEA 0183 sentences 41
NMEA 2000 PGNs 38, 40
NMEA 2000

PGN description 42

R

Rudder

Counter values 21
deadband, Auto,
Manual 12

feedback, calibration 14
Gain, ratio 21
Init, center, actual 23
Limit 24
minimum, activity 12
setup 13
source, VRF 13
Test 14
VRF, calibration 15
Zero position 18

S

Settings

Autotrim 23
Off heading limit angle 24
Sea trial 16
Steering profiles 23
Track response 24
Turn Rate 23
User 23

Setting

Course change confirm
angle, NAV mode 24
Manual speed 25
Sailing parameters 24
Tack angle 25
Tack time 25
Track approach angle 24
Turn patterns 25
Wind mode

Auto

Apparent

True 25

Setup

Compass, Device dialog,
Calibration option 16
Dockside 10

Supported data

NMEA 0183 sentences 41

NMEA 2000 PGNs ­NAC-3 40
NMEA 2000 PGNs,
NAC-2 38

T

Technical Specifications

NAC-2

Warranty 34, 35

NAC-3

Turn Patterns

C-turn 26
Depth countour tracking,
depth gain, CCA 27
Lazy-S turn 27
Spiral turn 27
Square turn 27
U-turn 26
Zigzag turn 27

U

Unit

Checking the
connectors 32
Preventive
maintenance 32

Update

Software, NAC-2 and
NAC-3 32

*988-11233-001*