Garmin | Nexus | Owner's Manual | Garmin Nexus Race Box

Garmin Nexus Race Box
RACE BOX
Installation and Operation Manual
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Edition: Mar 2012
This manual is written for Nexus RaceBox 1.00
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1 2 3 4 Part specification ................................................................................................... 5 Overview ................................................................................................................. 6 2.1 Calculated Data .................................................................................................................. 7 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 Mounting............................................................................................................................. 8 Serial / FDX Cable.............................................................................................................. 9 Pushbutton ......................................................................................................................... 9 Buzzer ................................................................................................................................ 9 Software Configuration ..................................................................................................... 10 Polar File .......................................................................................................................... 10 Configuration File ............................................................................................................. 11 Startup .............................................................................................................................. 11 Shutdown ......................................................................................................................... 12 4.1 4.2 4.3 4.4 Data Logging .................................................................................................................... 12 NXB Log ........................................................................................................................... 13 CSV Log ........................................................................................................................... 13 Target & Polar Boat Speed .............................................................................................. 14 4.5 4.6 4.7 4.8 4.9 4.10 Set Steer Memory ............................................................................................................ 17 Man Overboard (MOB) ..................................................................................................... 17 Start Line Tactical Assistance .......................................................................................... 17 In Sequence Data vs Out Of Sequence Data .................................................................. 18 Configuring which data is sent to which fields .................................................................. 18 Using the Race Box timer............................................................................................... 20 5.1 5.2 5.3 5.4 How does the Race Box choose its target? ..................................................................... 22 How does the Race Box choose the path to the target? .................................................. 23 Distance and time to line calculations .............................................................................. 23 Perpendicular Mode ......................................................................................................... 24 5.5 Other Configuration Options............................................................................................. 26 5.6 5.7 5.8 Status Lights..................................................................................................................... 27 Data Damping .................................................................................................................. 27 Error Conditions ............................................................................................................... 28 Installation .............................................................................................................. 8 Race Box Features and Their Use ...................................................................... 12 4.4.1 4.4.2 4.4.3 5 6 English
Polar File .................................................................................................... 15 Choosing Whether TBS or PBS is Sent to the Nexus Network.................. 15 Displaying TBS and PBS in Other Fields ................................................... 16 4.10.1 Starting the timer ...................................................................................... 20 4.10.2 Syncing the timer ..................................................................................... 20 Interpreting the data. What does it all mean?.................................................... 22 5.4.1 5.4.2 5.4.3 5.4.4 5.4.5 Starting examples ...................................................................................... 24 Reach in, reach out start ............................................................................ 24 The Vanderbilt start .................................................................................... 24 Other starting strategies ............................................................................. 25 Connecting a GPS Receiver ...................................................................... 25 5.5.1 5.5.2 Bow Location and Boat Length .................................................................. 26 Position Data Source ................................................................................. 26 AVAILABLE DATA FIELDS .................................................................................. 28 6.1.1 BIAS – Starting line bias ............................................................................ 28 6.1.2 PBS - Polar Boat Speed............................................................................. 28 6.1.3 TBS - Target Boat Speed ........................................................................... 29 6.1.4 TTL - Time to start line in seconds ............................................................. 29 6.1.5 TTB - Time to Burn..................................................................................... 29 3
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6.1.6 MTL - Meters to start line........................................................................... 29 6.1.7 FTL - Feet to start line ............................................................................... 29 6.1.8 BL - Boat Lengths to start line ................................................................... 29 6.1.9 OPT_A - The optimum apparent wind angle ............................................. 30 6.1.10 OPT_T – The optimum true wind angle .................................................. 30 Specifications ....................................................................................................... 39 7.1 Technical specifications Compss Instrument ................................................................... 39 Warranty ................................................................................................................ 39 4
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1 Part specification
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Items delivered with the Race Box
Qty
1
1
1
1
1
1
4
1
Description
The Race Box
push button
buzzer
DB9 male to DB9 female serial cable
power cable
SD memory card
Mounting screws
This manual
Registering this product
Once you have checked that you have all the listed parts, please take time to fill in the
warranty document and return it to your national distributor.
By returning the warranty card, it will assist your distributor to give you prompt and
expert attention. Keep your proof of purchase. Your details will also be added to our
customer database so that you automatically receive new product catalogues when
they are released.
Warranty conditions see 8.
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2 Overview
Thank you for purchasing the Nexus Race Box!
The Nexus Race Box is a great addition to any Nexus instrument system with an FDX
server. Our Race Box can calculate both polar and target boat speed (PBS & TBS), log
your instrument data in both Nexus native binary NXB format and comma separated
values (CSV) format and assist your tactician in making the best start possible. From
time to time, firmware upgrades will be released for the Race Box, and these can easily
be installed. Instructions for upgrading the firmware will be provided with each update.
Information generated by the Race Box is sent to Nexus instruments in accordance with
the Race Box configuration. This will be discussed in detail later in this manual, but in
general, you can send Race Box data to any NX2 or NXR instruments. This includes
the NX2 Multi, the Multi XL, the NXR Multi and the larger NXR instruments.
The Race Box is powered by 12 volts DC, just as the Nexus server is. A standard, DB9
male to DB9 female straight through serial cable connects the Race Box to the Server
data port.
To get the most out of your Race Box, you'll want to have a Nexus buzzer installed on
your FDX server and a Nexus push button connected to the Race Box. The Race Box
will provide the SET STEER and MOB functions you're used to, so you won't need an
additional button. In fact, with the Race Box, all these functions and more are controlled
with a single button. You can reuse the button that is currently connected to your server
if you have one.
The Race Box requires that a standard SD memory card be installed. This card will
have your polar table and your configuration file, both of which are read when the Race
Box starts up. Your log files will also be stored on this card. After your racing, you can
easily remove the card and use any computer with an SD card reader to review your
data.
The Race Box has four, full duplex RS-422 connections for communication with NMEA
0183 and other devices. Future firmware updates will allow the connection of some
peripherals to these connectors. In the initial release, you can connect a NMEA 0183
GPS receiver to the Race Box. The Race Box will accept the RMC sentence up to 5
times per second, for high speed position, COG and COG updates.
The Race Box also has three colored lights which can be seen through the translucent
case. These lights, referred to as the “status lights” or “status LEDs,” will be explained
in detail later in this manual.
Finally, the Race Box has connections for MOB, SET STEER and a buzzer. These are
for future use and currently are left unconnected.
How does it do all that?
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Fundamentally, all the Race Box does is accept data from the Nexus server, do some
processing on it and then sends the results to the Nexus server to be published on the
Nexus network. For the most part, this data is just displayed to the crew. In Classic and
NX2 series instruments, three special data fields exist which can hold calculated data.
These are TBS, CAD and CFD. TBS is a special field, and it is used only for speed
targets (more on this later). The NXR series supports these and ten additional fields,
referred to as CUSTOM0 through CUSTOM9. With the Race Box, the crew can
configure what information gets sent to each of these fields, within certain limitations.
For example, if the Race Box is calculating “time to line (TTL),” we have to tell it which
field to display this information in. If we have only NX2 instruments, then the choices
are CAD and CFD. With the NXR, we have ten additional choices.
So the primary method of giving the crew data while sailing is simply displaying the data
on the instruments. There are logs kept which can be viewed after you're done sailing.
The status lights also offer some information.
Once connected, data is received into the Race Box from the Nexus server. This is
done automatically. Also, there is a button that is used to control the Race Box and also
the Nexus server. This is used to tell the Race Box where the starting line begins and
ends, as well as to control some other features.
Like any computer, the not-so-old saying applies: Garbage in, garbage out. To get the
best information from the Race Box requires that your Nexus system be well calibrated
and that the crew understand how it works and what the numbers it is presenting mean.
This manual will explain all that for you and, if you have questions, you can contact
Nexus support.
2.1
Calculated Data
For a list of data fields that the Race Box can calculate, please refer to Appendix 'A'.
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3 Installation
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1.
2.
3.
4.
5.
The installation includes 5 major steps:
Read the installation and operation manual.
Plan where to install the RaceBox.
Run the cables.
Install the RaceBox.
Learn the functions and setting up your system.
Before you begin drilling ... think about how you can make the installation as neat
and simple as your boat will allow. Plan where to position the transducer and
instrument. Think about leaving space for additional instruments in the future.
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A few ”do nots” you should consider:
Do not cut the cables too short. Allow extra cable length at the RaceBox so
it can be disconnected for inspection without having to disconnect all
attached cables.
Do not run cables in the bilge, where water can appear.
Do not run cables close to fluorescent light sources, engine or radio
transmitting equipment to avoid electrical disturbances.
Do not rush, take your time. A neat installation is easy to accomplish.
•
The following material is needed:
Wire cutters and strippers.
Small and large Philips and a small flat head screw driver.
Hole saw to cut a hole for the instrument back of 63 mm (2½").
2.8mm drill for the RaceBox mounting screws
Plastic cable ties
If you are doubtful about the installation, obtain the services of an experienced
technician.
Installation
3.1
Mounting
First, find a suitable mounting location for the Race Box. Any location suitable for the
Nexus Server should serve equally well for the Race Box. You will notice that, just like
the Nexus server, the Race Box only has openings on one side. Also like the server, the
Race Box should be mounted so that it's bottom is against a vertical surface and the
side with the wire openings is oriented downward. This is so that any water which may
inadvertently splash on to the box is more likely to run off the box instead of into it. The
Race Box need not be mounted in close proximity to the server if this is your
preference, as long as you can connect a serial cable between the Race Box and the
Server.
Once you have located a suitable mounting location, use the four supplied mounting
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screws to mount the Race Box. You will beed to remove the outer lid to expose the
mounting holes. Once the Race Box is mounted, leave the outer lid removed until the
installation procedure is complete.
12VDC Power
Next, hook up power leads to the Race Box. The Race Box is powered by 12 Volts DC
and requires as much as approximately 0.17 amperes of current under certain
conditions (but typically uses much less). Please see the diagram in figure yyy to locate
the 12VDC connection terminal. You may connect the Race Box to the same power
switch/breaker as your Nexus server if you like. However, if you think you will want to
change your polar table during a day of racing without having to reset the rest of your
Nexus instrument system, then you will want to provide the Race Box with a dedicated
switch.
3.2
Serial / FDX Cable
The next step is to connect the supplied serial cable between the Nexus Server and the
Race Box. Be sure to tighten the thumb screws on the cable so that neither end falls out
while sailing. If the supplied cable does not reach, you can use any standard DB9 male
to DB9 female “straight through” cable such as can be bought at any computer store
and many other stores.
3.3
Pushbutton
Connecting a push button to the Race Box is optional, but if you do not connect one you
will not be able to use the timer and start line tactical functions of the Race Box.
We have supplied a weatherproof push button, but any normally open type push button
can be used. To connect the button, please refer to the diagram in figure yyy to locate
the proper screw terminals. When tightening the screws, please be careful not to over
tighten. Just make the connection finger tight, then verify that a firm tug on the wire
does not pull it from the terminal. If a firm tug does cause the wire to pull out, then
reconnect a bit more tightly.
If you are connecting your button to the Race Box only, then it does not matter which
side of the button is connected to which screw terminal. However, if your button is also
connected to an instrument such as a steer pilot, be sure that the button wire that is
connected to the ground side of your instrument is also connected to the ground
(negative) button terminal on your Race Box. Ideally, the button should be connected
only to the Race Box.
3.4
Buzzer
We strongly recommend that when the start line timing features of the Race Box are
used, that you have a loud buzzer installed on your Nexus Server. The buzzer is used
to generate an audio conformation that certain commands to the Race Box were
accepted correctly.
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Please refer to your Nexus Server manual for instructions on how to select and connect
a buzzer.
Done
You have now completed the hookup. Replace the outer lid and your installation is
complete.
3.5
Software Configuration
The Nexus Race Box is essentially a special purpose computer designed specifically to
interface with the Nexus instrument system. Because it is very feature rich and
powerful, it requires a bit more configuration than other Nexus products do. Don't worry
though, we will address everything you need to know both in this manual and on our
web site. You'll have your race box humming along in no time.
The Race Box accepts a standard SD memory card. This memory card can be written
to and read from using a standard personal computer running Windows or Linux and
also by a Mac. Many computers have a slot for reading SD cards already, but if your
computer does not you will need an SD card reader which plugs into your computers
USB port. These are available at many computer stores and also online. Reading files
from and writing files to this card is done exactly as you would read from or write to your
hard disk drive, your USB thumb drive and other similar memory peripherals.
3.6
Polar File
If you want the Race Box to generate either Target Boat Speed (TBS), Polar Boat
Speed (PBS) or both, you'll need to put your polar file on to the SD card. The difference
between PBS and TBS will be discussed later in this manual.
The polar file used by the Race Box uses the Nexus NXP polar format. This is the same
format used by the Nexus Race Software. Your polar files are typically supplied in a
number of formats, including NXP. If you bought your polar files from US Sailing, for
example, then you have them in NXP format. If you have your polar data in some other
format, please refer to Appendix 'D' for a description of the Nexus NXP polar format.
Polar files are just text data and you can easily edit another format to match NXP format
using a text editor such as Windows Notepad.
If you don't already have a polar file for your boat or if a polar file is not available, you
can make your own using log data from the Race Box. There are several web sites
dedicated to how to make polar files, and a little searching on the Internet will find a
wealth of information on making polar files.
Once you have your polar file ready, copy it to the SD card. You can name your polar
file whatever you like, but it must end in .NXP in order for the Race Box to recognize it.
Don't put more than one polar file on the card. The Race Box will use whichever it finds
first and you won't know which one it is using. If you have different polar files, perhaps
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for spinnaker and non-spinnaker racing, then store each polar file on a different SD
card. The easiest way to switch from one to the other will be to replace the SD card.
3.7
Configuration File
The Race Box has many different options and therefore requires a detailed
configuration file. Please refer to Appendix 'B' for a sample file. A default file was
included on your SD card. So that the Race Box can find it, the name of the
configuration file must be:
RP4N.CFG
The configuration file is a text file and the file name is not case sensitive. You can edit it
with a text file editor, such as notepad on Windows or TextEdit on a Mac, however you
should not edit it with a word processing program such as Microsoft Word. If you do
choose to edit it with a word processing program, be careful to make sure the file is
saved as a text file only. Do not save it in any other format, including RTF (rich text
format).
Each part of the configuration file will be explained as the features it controls are
discussed.
Finally, its very important to remember that you can not remove the SD card while the
Race Box is running, edit the config file, and replace it. The configuration file is only
read when the race box starts up. More important, removing the SD card while the
Race Box is running can corrupt the card's file system, erasing your data and possibly
even rendering the card completely unusable.
3.8
Startup
We're sure you anxious to get your Race Box to do something, so let's turn it on! Before
you power it up, put your polar file and a configuration file on to the SD card. If you do
not have a polar file, then use the default one supplied with the Race Box. With the
Race Box switched off, put the SD card in to the Race Box.
You can now power up your Race Box and Server. It is not important which is turned on
first. You may start the Server first, the Race Box first or both of them together.
Assuming everything is connected and installed correctly, you'll see the blue data light
on the Race Box come on. It will remain lit solid until the Server is powered on. As soon
as it begins getting data from the Server, it will be begin to flash steadily. Approximately
10 seconds later, it should begin flashing more rapidly and irregularly. This indicates
that the Race Box has successfully switched the Server into FDX mode and
communications are underway.
Occasionally, the Race Box will fail to switch the Server into FDX mode on the first try.
In this case, you will see the red error light come on briefly while the Race Box tries
again. Soon, the red light will go out and the blue data light will begin its irregular
flickering.
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Any time you see the blue data light flickering irregularly, you know that the Race Box
and the Server are communicating in FDX, and things are working correctly.
If you have not disabled logging in the configuration file, the Race Box has now opened
two log files. You can view these using a computer.
3.9
Shutdown
Shutdown procedure for the Race Box is easy enough. Just turn it off by removing
power to it. However, there is one very important caveat. Just as with a PC or Mac, an
SD card can not simply be removed from its socket. You must first “eject” it. On the
Race Box, we “eject it” by just turning off the Race Box. It is very important that you
never remove the SD card from the Race Box without first shutting down. If you do, it is
possible that you will corrupt the data on the SD card, rendering it corrupted and
possibly completely unusable.
After you shut off power to the Race Box, wait for all the lights (including the orange
power light) to be completely off before removing the SD card or restarting the Race
Box. The Race Box will not restart until it has completely powered down.
4 Race Box Features and Their Use
4.1
Data Logging
The simplest feature to use on the Race Box is data logging. The Race Box creates two
different types of logs. The first is the NXB log and the second is the CSV log. If you
have configured the race box to create either type of file, the Race Box will create the
log file each time it is turned on. The files will be named in sequence. The first log file
on the memory card will be named like this:
RACE_AAA.NXB
RACE_AAA.CSV
As you can see, each log file has an extension (the three character ending of the name)
which indicates what type of file it is. The log file names are selected in sequence.
Therefore, the next time the Race Box is started, it will see the files it already created
and create a new name, like this:
RACE_AAB.NXB
RACE_AAB.CSV
After that, they will be:
RACE_AAC.NXB
RACE_AAC.CSV
And so on until you get to ZZZ. At this point, you will have to erase some log files to
make room for more.
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NXB Log
The NXB log file is the Nexus native binary log in NXB format. This log is identical to the
logs generated by the Nexus Race software. In fact, you can transfer this log to a
computer and play back the sailing session in the race software. The race software will
work identically to how it would work if you had recorded the log using it in the first
place.
You can enable or disable this log by changing a setting in the config file. To enable this
log, ensure that the following line is in the Race Box configuration file:
NXB_LOG_FILE=ON
If you prefer that this log not be generated, then change the above line to:
NXB_LOG_FILE=OFF
4.3
CSV Log
The CSV log is a log of the data recorded, but not in binary form. This log is text data,
where each different field of text is separated by a comma. This is commonly referred to
as “comma separated values.” You can very easily import this data into another
program for analysis. Many programs, including small database programs, and
spreadsheets such as Excel or Open Office, are readily able to import this data.
Once its read in, you can perform any analysis you like. For example, you may wish to
use a spread sheet to create a chart which plots both target boat speed (TBS) and boat
speed (speed through water – STW) to see how well your crew maintained the correct
target boat speed. You may also wish to chart the true wind direction (TWD) to see
what type of shifts you experienced.
You can enable or disable this log by changing a setting in the config file. To enable this
log, ensure that the following line is in the Race Box configuration file:
CSV_LOG_FILE=ON
If you prefer that this log not be generated, then change the above line to:
CSV_LOG_FILE=OFF
In the case of the CSV file, you can control how frequently the Race Box adds a line of
data. The fastest logging rate is 5 seconds. You can set it to another value, such as 10
seconds, like this:
CSV_LOG_INTERVAL=10
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4.4
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Target & Polar Boat Speed
The Race Box can calculate and present either Target Boat Speed (TBS), Polar Boat
Speed (PBS) or both.
Whats the Difference?
When a boat is sailing upwind, it can sail higher (decreasing its true wind angle) and
shortening the distance it needs to sail, but this causes it to sail more slowly, increasing
its travel time. Conversely, it can sail lower (increasing its true wind angle) which will
increase the distance the boat needs to sail but increase its speed. For any given True
Wind Speed (TWS), somewhere between zero degrees True Wind Angle (TWA) and 90
degrees TWA there is a sweet spot; a perfect TWA which is the optimum balance of
boat speed and distance.
This is also true downwind. Of course, all sail boats can sail with the wind exactly
behind them, dead down wind. But for almost all boats, its faster to gybe back and forth,
since your boat can reach faster than it sails down wind, even though this increases the
distance you need to sail. When sailing downwind, somewhere between 90 degrees
TWA and 180 degrees TWA, there is a TWA that produces the optimum combination of
boat speed and distance.
For any given true wind speed (TWS), these optimum TWAs change. When sailing at
the optimum TWA, your boat is traveling at a particular boat speed. This boat speed is
known as the Target Boat Speed (TBS). If you're actual boat speed is faster than your
target, you may want to head up to slow down but shorten your distance. If its slower,
you may want to head down to increase your distance but speed up.
If you choose to have the Race Box send Target Boat Speed to the Nexus TBS field
(more on this later), the Race Box will send the optimum TBS for the current wind
velocity. This means that if your TWA is less than 90 degrees (that is, you're sailing
upwind), the Race Box will send the upwind target that corresponds with the current
wind velocity. If your TWA is lower than 90 degrees, the optimum down wind TBS is
sent to the Nexus server.
Polar Boat Speed (PBS) is a simple concept. It is the speed at which your boat should
be traveling through the water given the current wind velocity and TWA. If you chose to
have PBS sent to the TBS field, The Race Box will send the speed at which your polar
table predicts you will be traveling given the existing TWA and TWS, even if the TWA is
above or below the optimum angle for these conditions.
Which one is better to use is a always a matter of an opinion and usually depends on a
variety of factors. Many people prefer to use TBS when racing a windward / leeward
course, while other courses may command PBS. Some drivers prefer to just write the
targets out on to the deck and send PBS to the instruments. There is no right or wrong
way to do it. You'll have to choose based upon your preferences.
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Polar File
To do this, the Race Box needs a “polar file.” A polar file is a list of boat speeds and
wind angles. These files can be generated by computer programs which know about a
boats hull shape, weight, rig dimensions and other factors. If you want to purchase a
polar file for your boat, contact US Sailing. There are also a lot of polar tables on
www.blur.se. Or, a polar file can be created by recording data about how a boat actually
performs at a variety of wind speeds and angles. The Race Box logs are a great way to
record this information.
Your polar file must be put on the Race Box SD card. As mentioned earlier, the polar
file should be in standard Nexus polar file format. The file name must end in .NXP and
the file must be placed on to the SD card so it can be read by the Race Box at startup.
If you don't have a polar table or just prefer not to use one, then set the following
configuration option in the rp4n.cfg file like this:
USE_POLAR_TABLE = N
When this is set, the Race Box will not try to load the polar file at startup, so no polar file
is necessary on the SD card. Also, it will not be able to calculate PBS or TBS
information.
TBS and PBS are both calculated by checking the true wind speed (TWS) and your
current true wind angle (TWA), and then applying this information to your polar table. Of
course, this information varies as the wind speed and your sailing angle does.
The data in polar files also needs to be adjusted for the height of your wind transducer
above the water surface. Many people manually edit the data in their polar file, but this
is not necessary since the Race Box will compensate for transducer height. In order for
it to do this, the configuration file needs to be told the height of the transducer above the
surface of the water, in feet. The proper line in the configuration file is:
WIND_XDUCER_HEIGHT=43
If you have already adjusted your polar file to compensate for your transducer height,
then set the height to 0, like this:
WIND_XDUCER_HEIGHT=0
4.4.2
Choosing Whether TBS or PBS is Sent to the Nexus Network
The Nexus instrument system has a data field called TBS, but this field can be used
either for target boat speed or polar boat speed. The Race Box configuration file
controls what information is sent to this field. This information is then published
throughout the Nexus network and all instrument features related to TBS can be used.
For example, all of the NX2 and NXR instruments have the ability to simply present the
value of the TBS filed, in knots, as a number. Also, the NX2 Wind Instrument can trim
on TBS. When the Wind Instrument is set up to do this, it has an indicator which raises
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when you are sailing above your target speed, and lowers when you are below it.
Similarly, the Multi XL has a trim feature which will tell you what percentage you are
below or above your target speed. NXR instruments have similar features.
You can control whether it is TBS or PBS which is sent to the Nexus network by
changing a setting in the Race Box configuration file. If you wish to send PBS to the
network, ensure that the following line is in the configuration file:
TBS_DATA=PBS
If you prefer that TBS be sent to the network, then change the above line to:
TBS_DATA=TBS
Be sure you do not have both lines in the file at the same time, unless of course one of
them is commented out.
4.4.3
Displaying TBS and PBS in Other Fields
If you like, you can also cause the value of both TBS and PBS to be displayed in other
fields. The Nexus system has “custom data fields” which can display certain types of
data. These are available on the NX2 instruments and the Multi XL instruments and
some of the NXR instruments. The NXR instruments have ten “custom data fields”
which can display other information. For example, they can display information from
load cells. We can tell the Race Box to send TBS and PBS to them for display. You
won't be able to use the trim percentage or other TBS specific functions, but you will be
able to see the target speed so you can compare it to your actual speed.
To do this, set the following lines in the configuration file:
CAD=PBS
CFD=TBS
These lines will cause polar boat speed to be sent to the CAD field and target boat
speed to be sent to the CFD field. To send data to the custom fields of the NXR series:
CUSTOM0=TBS
CUSTOM1=PBS
This will cause target boat speed to be sent to custom 0 while polar boat speed is sent
to custom 1. If you wish to send this data to different custom fields, simply change the
number after the word CUSTOM. Valid numbers are from 0 to 9.
Please refer to the manuals for your NX2 or NXR instruments to learn how to make
CAD, CFD and CUSTOM0 through CUSTOM9 display.
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Set Steer Memory
You can use the Set Steer, or wind memory, feature of your Nexus server by pressing
the button connected to your Race Box. You won't need an additional button connected
directly to your server.
To set the steer memory, press the button once for about a half a second and release it.
If there is a buzzer connected to your server, you will her one short beep. The steer
memory will be updated and your steer pilot instrument will function as expected.
4.6
Man Overboard (MOB)
You can use the man overboard function of your server by pressing the button
connected to your race box. You won't need an additional button connected directly to
your server.
To trigger a man overboard (MOB) condition, do five (5) consecutive short presses of
the button. Each short press should be about half a second long. The MOB function will
be triggered and your Nexus system will behave exactly as it would if the button were
connected directly to the server.
Also, the Race Box will write a text file to the SD card. This file will contain the position
and time that the MOB function was triggered.
4.7
Start Line Tactical Assistance
The Race Box is able to provide assistance to the crew before and during the starting
sequence by providing data about the starting line and your position relative to it. Using
the Race box, you can find out:
• Starting line bias relative to the true wind direction (BIAS)
• Your distance from the starting line in boat lengths, meters or feet (BL, MTL or FTL)
• The time required to reach the line on your current course and speed (TTL)
• The time you will be late or early to the line (time to burn – TTB)
In order to get this information from the Race Box, you need to tell the Race Box where
each end of the start line is. In order to get time to burn, you'll also need to tell the Race
Box when the starting sequence began (discussed more under Timer).
Pinging the Line
In order to tell the Race Box where the start line begins and ends, we approach each
end of the line with the boat's bow and press the button. The ends can be pinged in
either order. Also, if the race committee moves either end after you have pinged the
line, you need only re-ping the end that they moved.
To ping the right hand end of the line, slowly bring your boat's bow as close to the end
mark as you can before the PRO begins screaming and throws his or her coffee at you.
When your bow is as close as it can get, do two quick presses on the button. If you do it
correctly, the server buzzer will emit two short beeps. Also, the green info light on the
Race Box will begin flashing slowly.
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To ping the left hand end of the line, slowly bring your boat's bow as close to the pin as
you can. When your bow is as close as it can get, do three quick presses on the button.
If you do it correctly, the server buzzer will emit three short beeps and the info light on
the Race Box will light on solid.
If you ping the left hand end of the line first, the green info light will flash rapidly, then
light solid when you pine the right hand end.
At this point, the location of both ends of the starting line, as well as its compass
bearing, have been computed and stored in the Race Box's memory. We're now ready
to start!
4.8
In Sequence Data vs Out Of Sequence Data
As mentioned earlier, the Nexus system has a number of “custom fields” into which we
can send whatever data we like. The NX2 series, including the Multi XL instruments,
offers the CAD, CFD and TBS fields. TBS is only used for speed targets, so that leaves
us with just CAD and CFD. The NXR series offers ten additional fields, called custom 0
through custom 9.
The Race Box attempts to expand options by allowing the crew to configure it to send
certain data to a particular field while in the starting sequence, and other data to that
same field both before the starting sequence has begun and after the starting sequence
is complete. For example, we might display “Time To Burn – TTB” in the CFD field for
the period of time between when we started the timer and when the gun sounds. At the
gun, the CFD field will change and display optimum apparent wind angle.
Data which is sent to any particular field during a starting sequence is referred to as “in
sequence data” while data sent to any particular field before the start timer is started or
after the timer reaches zero is referred to as “out of sequence data.”
4.9
Configuring which data is sent to which fields
As discussed earlier in the overview, the Race Box primarily accepts data from the
Nexus server, performs various calculations on this data and sends the results back to
the Nexus server to be published on the Nexus network.
With one exception, the various fields in the Nexus network accept data and only
display it. The exception is the TBS field. Instruments can display the TBS sent to them
in knots, but also have special features which can show more information about TBS,
such as the percentage your current boat speed is above or below your current TBS.
Therefore, it only makes sense to send either TBS or PBS to the Nexus TBS field.
The Classic and NX2 instruments, including the Multi XL, can accept two additional
fields, called CAD and CFD. The CAD field can display values from 0 to 359 as whole
numbers. The CFD field can accept data from ? To ?, but with decimal
portions. Because of differences in how these fields display data, its better to send
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some data types to CAD and others to CFD.
Because they are represented as whole numbers, the best choices of data to send to
the CAD field are:
BL
OPT_A
OPT_T
The best choices to send to the CFD field are:
BIAS
TTB
TTL
The time fields will have a dot in the display, such as 3.40. In the case of the time fields,
this means 3 minutes and 40 seconds. In the case of an angle, such as bias, it
represents 3.40 degrees.
The NXR series instruments have the ten custom data fields, so any type of data
generated by the Race Box can be sent to any of those ten custom fields.
The Race Box is told which data to send to which field in its configuration file. Here is
an example from the config file:
CAD_IS=BL
CFD_IS=TTB
;
CAD_OS=OPT_T
CFD_OS=BIAS
The first line, CAD_IS=BL, means that the BL (boat length) data calculated by the Race
Box will be sent to the CAD field of the Nexus network while the starting sequence is in
progress. In short, CAD_IS means CAD field while in sequence. Likewise, CFD_IS
means CFD field while in sequence. Conversely, CAD_OS means CAD field while out
of sequence and CFD_OS means CFD field while out of sequence.
Therefore, before you begin the starting sequence and after the sequence ends, the
example above will cause the optimum true wind angle to be sent to the CAD field while
the start line bias will be sent to the CFD field. As soon as you trigger the start timer,
CAD will begin displaying boat lengths to line (BL) and CFD will begin displaying time to
burn (TTB).
If you prefer that no data be sent to a field, you can set it to “OFF” like this:
CFD_OS=OFF
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4.10 Using the Race Box timer
The Race Box start timer can work independently of the rest of the Nexus system or it
can trigger the Nexus start timer. Either way, it can be configured to start counting down
from any number of minutes desired. You do not have to use it, but if you don't, then
TTB and other in-sequence calculations can not work. This is because unless the timer
is started, the Race Box will never know that you are “in sequence.”
Configuring the timer
To set the number of minutes the Race Box timer will run, use the LONG_PRESS
option in the configuration file:
LONG_PRESS=5
This will start the timer at 5 minutes. Valid parameters are even numbers from 1 on up
to 60. If you do not want to use the Race Box timer, you can set this parameter to either
0 or to MOB, like this:
LONG_PRESS=MOB
If you set the parameter to MOB, then a long press (a press of at least 1 second or
more) will trigger a MOB condition, just as 5 quick presses does.
4.10.1
Starting the timer
The timer is started by pressing and holding the button for at least one full second, and
then releasing it. The timer starts at the instant you release the button. The Nexus
Server can not notify the Race Box that a timer has been started, so you can not start
the Race Box timer from an instrument.
4.10.2
Syncing the timer
Like many popular start timer watches, the Race Box allows you to “sync down” the
timer. While the timer sequence is running, you can advance the timer down to the next
minute by doing one quick press on the button.
Say, for example, you just heard the 10 minute sound, and you start the timer 12
seconds late. As the next sound approaches, you can wait for it with your finger on the
button, and quick press as soon as you hear the sound. Your timer will move from 5:12
to 5:00 instantly, synchronizing your timer with that of the race committee.
When you are using this synching feature in conjunction with the Nexus timer, there is
an important limitation which will be described in the next section.
Having the Race Box timer start the network timer
You can have the Race Box timer start the Nexus network timer at either 5 minutes or
10 minutes. To do this you must:
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• start the Race box timer for at least 5 minutes of you want to start the Nexus timer at
5 minutes
• start the Race box timer for at least 10 minutes of you want to start the Nexus timer
at 10 minutes
• set the proper parameter in the configuration file, like this
; To start the Nexus timer with 5 minutes remaining
USE_NEXUS_TIMER=5
; To start the Nexus timer with 10 minutes remaining
USE_NEXUS_TIMER=10
; To not use the Nexus timer at all
USE_NEXUS_TIMER=0
If you set the USE_NEXUS_TIMER parameter to a number greater than the
LONG_PRESS parameter is set to, the Nexus timer will never be started.
Also, once the Nexus timer has started, it is no longer possible to sync the timer down.
This is because the Nexus network timer has no ability to be synched.
If you have a 5 minute starting sequence and you wish to use the Nexus timer, you
would configure like this:
LONG_PRESS=5
USE_NEXUS_TIMER=5
In this case, both the Race Box and network timers are started the instant you do a long
press on the button, and there is no ability to sync down.
If you have a 10 minute starting sequence and you wish to use the Nexus timer, you
would configure like this:
LONG_PRESS=10
USE_NEXUS_TIMER=5
In this case, the Race Box timer is started the instant you do a long button press. You
will be able to sync down for 5 minutes until there is 5:00 remaining. The network timer
will be started at 5:00.
If you have a 13 minute starting sequence, perhaps in a pursuit race with a new start
each minute, and you wish to use the Nexus timer, you would configure like this:
LONG_PRESS=13
USE_NEXUS_TIMER=5
In this case, the Race Box timer is started the instant you do a long button press. You
will be able to sync down for 3 minutes until there is 5:00 remaining. The Nexus network
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timer will be started at 5:00.
Viewing the time remaining on the Race Box timer
You can view the time remaining on the Race Box timer in the CFD field by setting the
configuration file like this:
TIMER_CFD=Y
This will cause the time remaining on the Race Box timer to be displayed in the CFD
field. The time will only be displayed until the Nexus network timer is started. After that
point, whatever you have set in CFD_IS will then take over.
If you start the Race Box timer and the Nexus network timer at the same number of
minutes (that is, either 5:00 or 10:00), then the CFD field will never display the Race
Box timer value simply because it will never be running when the network timer is not.
Conversely, if you set TIMER_CFD to Y but you do not use the network timer
(set USE_NEXUS_TIMER to 0) then the Race Box timer will always display the time
remaining during the starting sequence, and the CFD_IS data will never be displayed.
The advantage of this is that you'll be able to sync down right to the last minute.
5 Interpreting the data. What does it all mean?
The algorithms used by the Race Box for start line timing are straightforward, but it is
important to understand what it is doing so that the crew can make the best possible
use of the information presented. This section will explain how the Race Box derives
the numbers it presents.
At the most basic level, the Race Box is calculating your position, speed and heading
relative to that of the starting line. All the data for start line timing calculations comes
from the GPS receiver connected to the Race Box. Because the starting line is
anchored to the ground, the Race Box needs to use ground relative data to do its job.
So, it uses position, course over ground (COG) and speed over ground (SOG) from the
GPS receiver.
The Race Box “targets” a position somewhere along the starting line and calculates the
distance to that position from your bow along a particular path. For the crew, using the
data effectively requires that you understand both (1) where the target point is and (2)
what the path is to the point being targeted.
5.1
How does the Race Box choose its target?
Imagine a line running along the center of your boat, extending exactly forward and aft
from your mast and that this line extends off the boat, both forward and aft. This line
either intersects the starting line or it does not. If this line intersects the start line, the the
intercept point of your centerline and the start line is the target. If this line does not
intersect the starting line, then whichever end of the line is closer to the bow becomes
the target.
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More simply put, if the start line is directly in front of you or behind you, then the start
line is the target. Otherwise, its whichever end of the line is closer to your bow.
5.2
How does the Race Box choose the path to the target?
The path to the target is simple. Its a straight line from your bow to the target. If the
centerline intersects the start line then the target is a straight path to the line, either in
front of you or directly behind you. Otherwise, the path is to whichever end of the line is
closer.
5.3
Distance and time to line calculations
Now that we know the target and the path to the target, its simple to calculate the
distance to the target. Remember, its the distance from your bow to the target,
regardless of your heading. Distance to the line can be presented in feet (FTL), meters
(MTL) or boat lengths (BL).
Time to the line (TTL) is calculated based upon the distance to the target point and your
current speed over ground. If your current course over ground will take you across the
starting line then the distance to line and time to line calculations will be fairly accurate.
If your target is one end of the line and you are not currently on a heading that takes
you directly to or away from the line, you must take into consideration several items.
First, when you turn to head toward the line, the target will change when your centerline
actually intercepts the line. Second, you should consider the time it will take to turn your
boat. Finally, consider that the speed of your boat will change after you turn it and come
up to speed on a new sailing angle (relative to the wind).
Time To Burn (TTB) calculations
Time To Burn tells the crew whether they will be early or late to the starting line, based
upon the time to the line and also based upon how much time is remaining before the
start. To calculate this data, the Race box takes your Time To Line (TTL) and subtracts
it from the time remaining until the gun.
If your TTL is 30 seconds and there are 40 seconds remaining before the gun, then
your TTB is +10; you need to “burn” off 10 seconds to avoid being late. Conversely, if
your TTL is 30 seconds and there are only 10 seconds to the gun, then your TTB is -20
and you're 20 seconds late. And of course if your TTL is 30 with 30 seconds left before
the gun, your TTB is 0.
Be careful with TTB. Always be mindful that pinging the line can only be so accurate,
and that the GPS receiver typically is off from 3 to 9 feet (1 to 3 meters). Wind
conditions can change quickly and there is always that other boat rudely stealing the
space you planned to put your boat into. Therefore, you will still want the crew making
their approach estimations on your final approach to the line.
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5.4
Perpendicular Mode
If you prefer a simpler method, you can set the Race Box line calculations into
perpendicular mode by setting a line in the configuration like this:
LINE_PERF_ONLY=Y
Doing this changes how the Race Box calculates your distance to the line. The distance
is still from the bow, but it is always along a path that is perfectly perpendicular to the
starting line or its extensions. Regardless of your current heading, this distance will
always be calculated straight to the line or its extension.
Some people prefer this method of calculating line distance. However, this mode
deceases the accuracy of the data reported.
5.4.1
Starting examples
Here are some commonly used starting strategies, with an explanation of what the
Race Box will do.
5.4.2
Reach in, reach out start
One of the simplest starting techniques is the reach out, reach in technique. Simply
enough, you reach along the line and as you pass the end, you note the time remaining.
Subtract the time required to gybe around, divide by two and you know how many
seconds before you need to head back.
Let's assume you are to the left of the pin end, reaching toward it. As you approach it,
the Race Box will be selecting the pin as its target and telling you DTL, TTL and TTB
based upon how far that pin is away from your bow. The pin is targeted because your
centerline is not intersecting the start line.
As you pass the pin, still on course for the other end of the line, the Race box will
continue to target the pin until your bow is half way down the line. At this point, the other
end of the line becomes closer and the Race Box switches to target that end. DTL and
TTL decrease as you approach the boat end of the line.
When you pass the committee boat, the Race Box will continue to target it and TTL and
DTL will increase. TTB will be decreasing rapidly at this point, since you are moving
away from the line and the clock is ticking down. Let's assume you know that it takes
about 15 seconds to gybe the boat and head back to the committee boat for a start.
Watch the TTB. When the TTB indicates 15 seconds, its time to gybe. After you do,
head straight back to the boat end of the line and the TTB will indicate approximately 0
all the way back to the committee boat.
5.4.3
The Vanderbilt start
Similar to the reaching out and back start is the Vanderbilt start. You sail away from the
starting line on a broad reach, then at the right time turn around and beat back to the
line.
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As you sail away from the starting line, your TTB will be increasing rapidly, just as when
you are reaching away from the end of the line in a reach out reach back start. The
difference is that your centerline will be intersecting the starting line, so the Race Box
will be targeting the actual starting line, not one of its ends.
Once again, when the TTB hits 15 seconds (or however long it takes you to gybe your
boat), gybe around and head back to the line. Sail at your optimum wind angle straight
for the line, or perhaps a bit lower for extra speed. The centerline of your boat,
projected forward, should be intersecting the starting line, and the Race Box is targeting
that intercept point. Your TTL, TTB and distance to line is all based upon the distance
you have to sail on your current course over ground to cross that line, and the speed at
which you are currently sailing.
5.4.4
Other starting strategies
These examples are designed to give you an understanding of hat the Race Box does
in certain situations during the start. Of course there are any number of different ways
to approach a starting line. The Race Box can assist, as long as you keep in mind how
it works so you can interpret the data it presents to you. As with any instrument, its up
to the crew to interpret the data to put it to best use.
5.4.5
Connecting a GPS Receiver
The Race Box can accept GPS data from the Nexus server or directly via its own
NMEA 0183 ports.#
If you have a NMEA 0183 GPS connected to the Nexus server via the servers NMEA
port, the server will report position, speed over ground and course over ground to the
Race Box at a rate of approximately 1 update every two seconds.
If you have a Nexus nGPS connected to the Nexus network bus, the server will report
position at a rate of two updates per second and speed and course over ground at 5
updates per second.
You can also connect a NMEA 0183 GPS directly to the Race Box. The Race Box will
accept the NMEA 0183 RMC and ZDA sentences at a baud rate up to 57,600 baud and
an update rate up to 5 times per second.
To hook it up, remove the outer lid and connect the GPS NMEA 0183 or RS-422 output
to port RX1 on the Race Box. As with the other connections, be careful not to over
tighten the screws. Make them just finger tight. Near the upper right hand corner of the
circuit board, you will see two jumpers. One of these is labeled “USB.” Move the jumper
shunt so that inner pin and middle pin are connected. Replace the outer lid.
Finally, a change to the configuration file needs to be made. Please refer to “Other
Configuration Options” and then “Position Data Source” below for details.
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5.5
Other Configuration Options
This section reviews miscellaneous configuration options and features which were not
addressed elsewhere in this manual.
5.5.1
Bow Location and Boat Length
To get the most accurate location data possible, the Race Box must be told how far aft
the GPS antenna is mounted on your boat. This number is in feet, may have a decimal
portion and is put in the configuration file like this:
; Specify boat length overall in feet. You may specify a
; decimal of a foot, such as 28.5.
;
BOATLENGTH=30
To tell the Race Box where the GPS antenna is mounted, enter it into the configuration
file like this:
; The number of feet aft from the bow where the GPS antenna is
; mounted. On a 30 foot boat, if the GPS antenna is on the
; very back of the stern, then this should be 30. You may
; specify a decimal of a foot, such as 22.7.
;
GPS_ANTENNA_LOCATION = 30
5.5.2
Position Data Source
The Race Box can take its position either from the Nexus Server or directly from a GPS
receiver (see “Connecting a GPS Receiver” earlier in this manual). In order to get
position data from the Nexus server, you need either a NMEA GPS receiver connected
to the Nexus servers NMEA in port or a Nexus nGPS receiver connected directly on the
Nexus network.
If the position data comes from the server, enter this line into the configuration file:
POSITION_DATA_SOURCE = F
The ‘F’ is for FDX.
You can also connect a NMEA GPS receiver directly to the Race Box on one of its
NMEA input ports. Currently, only NMEA port RX1 is supported. Data from a NMEA
GPS must be NMEA 0183 sentence RMC and the Race Box can accept up to 5 RMC
sentences per second. You can also set the baud rate. All standard baud rates up to
57,600 baud are supported. If your NMEA 0183 GPS can update at a rate of 5 updates
per second, you should set the baud rate to 57,600 baud.
To receive NMEA 0183 position data directly into the Race Box, at a baud rate of
38,400 baud, set the configuration file like this:
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POSITION_DATA_SOURCE = F
POSITION_NMEA_DATA_RATE = 38400
5.6
Status Lights
The Race Box has three small lights referred to as “status lights” or also “status LEDs.”
The use of these lights has been explained, but they consume battery power. You may
prefer that they be shut off so that the Race Box will use less of your battery.
Each light can be configured to be on or off independently. To turn them off, set a line
for each in the configuration file like this:
DATA_LED=OFF
INFO_LED=OFF
ERROR_LED=ON
With this configuration, the data light and the info light will be off and the error light will
be on.
When set to off, the data light will turn itself off as soon as FDX communication is
established with the server. The info and error lights, when set to off, will never come
on. We recommend that the error light always be left on, since it rarely lights and only
does so when there is a good reason.
5.7
Data Damping
The Race Box can dampen the data it uses to calculate the data it sends to the server.
When damping, it can do so in the same manner that the NX2 instruments do, or it can
just average over a number of seconds. This is controlled for four data fields, PBS,
TWA, TWS and BSP.
The following lines in the configuration file control which method is being used. If the
NX2 method is used, the DAMP_LEVEL parameter is the NX2 damping level. If the
NX2 method is not used, then the DAMP_LEVEL is the number of seconds the data is
to be averaged over.
; A Y here will cause the RP4N to use the Nexus damping scale.
; Any setting other than Y will use the number of seconds. In
; both cases, the number must be a whole number of 0 or greater.
;
USE_NEXUS_DAMP_SCALE_PBS=N
DAMP_LEVEL_PBS=5
;
USE_NEXUS_DAMP_SCALE_TWA=N
DAMP_LEVEL_TWA=5
;
USE_NEXUS_DAMP_SCALE_TWS=N
DAMP_LEVEL_TWS=5
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;
USE_NEXUS_DAMP_SCALE_BSP=N
DAMP_LEVEL_BSP=5
5.8
Error Conditions
If the Race Box encounters a condition it can not handle, or is there is an error of some
type with the configuration, it signals this problem by flashing the red error light.
Different flash patterns are used to signal different errors.
Some errors are fatal; the Race Box can not recover from them. Others are temporary
or just a notice, and corrective action can be taken.
Please see Appendix C for a complete list of errors.
6
AVAILABLE DATA FIELDS
This appendix reviews the type of data fields which the Race Box can generate.
The Nexus Race Box is capable of calculating the following data fields and sending
them to the Nexus network:
6.1.1
BIAS – Starting line bias
This field reports the bias, sometimes referred to the “favored end” of the starting line.
Data is reported in plus or minus degrees, such as +3.2 degrees. As such, this field is
best reported on NX2 instruments as CFD and on NXR instruments as one of the ten
custom data lines.
If the number is positive, then the right end of the line is further upwind. A negative
number indicates the left end of the start line is further upwind.
A perfectly square starting line will be 90 degrees relative to true wind. Of course, even
the best race committee often has trouble establishing the perfect line, and even as
they do, slight wind shifts will change the line bias. The number of degrees reports the
number of degrees by which the line is not square. If the BIAS is reported as 5 degrees,
then the angle between the true wind direction and the starting line is 95 degrees. If the
number is -3 degrees, then the angle between true wind direction and the starting line is
87 degrees.
6.1.2
PBS - Polar Boat Speed
Polar Boat Speed is the optimum speed the boat should be traveling given the current
true wind angle (TWA) and true wind speed (TWS).
PBS is typically used on a course other than a windward leeward course or an offshore
race.
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TBS - Target Boat Speed
Target Boat Speed is the optimum speed the boat should be traveling, given the current
true wind speed, assuming it is traveling on the optimum upwind or downwind angle for
maximum speed to a windward or leeward mark.
If you are sailing above 90 degrees, the Race Box will use your polar table to calculate
the optimum upwind angle for the current true wind speed, then calculate the proper
target boat speed for that true wind angle and report it.
Conversely, if you are sailing below 90 degrees, the Race Box will use your polar table
to calculate the optimum downwind angle for the current true wind speed, then calculate
the proper target boat speed for that true wind angle and report it.
TBS is typically used on a windward leeward course.
6.1.4
TTL - Time to start line in seconds
The amount of time in seconds until the boats bow will intercept the start line if it
remains on its current heading at its current speed.
6.1.5
TTB - Time to Burn
The amount of time the boat will be early or late to cross the starting line on its current
heading at its current speed. If the boat will be early, a positive number is displayed. For
example, 15 means fifteen seconds early. A negative -5 means you will reach the line
five seconds after the gun.
TTB can only work when the Race Box timer feature is used, because calculating TTB
requires that the Race Box know how much time is left until start.
6.1.6
MTL - Meters to start line
The distance to the start line, along the boats current heading, in meters.
6.1.7
FTL - Feet to start line
The distance to the start line, along the boats current heading, in feet.
This number is actually less useful than it seems. Its an extremely fine measure, and in
reality its not possible to achieve this level of accuracy with eh Race Box, or any other
similar tool. Accuracy is impacted by how well the line ends were pinged and also by
the current accuracy of the GPS receiver. On a moving vehicle, the current state of
GPS technology does not allow for accuracy greater than about 9 feet, although it can
sometimes be as good as 4 feet.
6.1.8
BL - Boat Lengths to start line
The distance to the start line, along the boats current heading, in boat lengths. This
requires that we tell the Race Box the length of the boat using the configuration file.
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6.1.9
OPT_A - The optimum apparent wind angle
When sailing above 90 degrees, this field will contain the optimum apparent wind angle
that the boat should be sailing to achieve the correct upwind target boat speed, given
the current true wind speed.
Conversely, when sailing below 90 degrees, this field will contain the optimum apparent
wind angle that the boat should be sailing to achieve the correct downwind target boat
speed, given the current true wind speed.
6.1.10
OPT_T – The optimum true wind angle
When sailing above 90 degrees, this field will contain the optimum true wind angle that
the boat should be sailing to achieve the correct upwind target boat speed, given the
current true wind speed.
Conversely, when sailing below 90 degrees, this field will contain the optimum true wind
angle that the boat should be sailing to achieve the correct downwind target boat
speed, given the current true wind speed.
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APPENDIX A - SAMPLE CONFIGURATION FILE
; rp4n.cfg
;
; This is the configuration file for RP4N
;
; Any line that begins with a ; will be ignored and can
; be used for comments
;
;
; This parameter specifies whether or not a polar table should
; be used. If omitted, this parameter defaults to Y. If this
; parameter is set to N then the RP4N will not attempt to load
; a polar table from the SD card and also will not calculate
; PBS/TBS or optimum wind angles.
;
USE_POLAR_TABLE = Y
;
;
; Log files
;
CSV_LOG_FILE=ON
NXB_LOG_FILE=ON
;
;
; How frequently do you want to save entries to the CSV log
; file? Enter a whole number of seconds equal to or greater
; than 5. This parameter defaults to 5.
;
CSV_LOG_INTERVAL=5
;
;
; These parameters specify whether position data (Lat/Lon) is
taken
; from the Nexus server via FDX or whether the position data is
; accepted directly into the RP4N and if so on which channel.
;
; Set this parameter to 'F' to accept data via FDX from the
Nexus
; server, or 0 to 3 to accept position data via NMEA 0183
directly
; into the RP4N. See the RP4N manual for additional information
; including wiring instructions and hardware switch
configuration
; instructions. This parameter defaults to 'F'. NOTE: Currently
only
; F and NMEA 0182 channel 0 are supported.
;
POSITION_DATA_SOURCE = F
;POSITION_DATA_SOURCE = 0
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;
; If POSITION_DATA_SOURCE is set to a NMEA 0183 channel, then
use
; this parameter to set the baud rate. Only standard baud rates
are
; supported. This parameter defaults to 4800 baud. See the
; instruction manual for further details.
;
POSITION_NMEA_DATA_RATE = 38400
;
;
;
; The status LEDs can be turned off to conserve
; power. Each LED uses up to 20ma when on solid.
;
; Valid settings are ON or OFF
;
DATA_LED=ON
INFO_LED=ON
ERROR_LED=ON
;
;
; The damping level for TBS and TWA can be set here. Two choices
; for damper setting are available. You can use the exact
; same scale as Nexus uses, which is from 0 to 9. Alternatively,
; you can simply set the number of seconds. If you set the
; number of seconds, then the RP4N will average all the
; past TBS values for the past n seconds, where n is whatever
; value you set, and present this result.
;
; A Y here will cause the RP4N to use the Nexus damping scale.
; Any setting other than Y will use the number of seconds. In
; both cases, the number must be a whole number of 0 or greater.
;
USE_NEXUS_DAMP_SCALE_PBS=N
DAMP_LEVEL_PBS=5
;
USE_NEXUS_DAMP_SCALE_TWA=N
DAMP_LEVEL_TWA=5
;
USE_NEXUS_DAMP_SCALE_TWS=N
DAMP_LEVEL_TWS=5
;
USE_NEXUS_DAMP_SCALE_BSP=N
DAMP_LEVEL_BSP=5
;
;
;
; How frequently should the PBS/TBS display be updated? Enter a
; whole number of seconds 1 or greater. This parameter defaults
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; to 2 seconds.
;
UPDATE_SECONDS_PBS=2
;
;
;
; What does a long press do? Options are:
; MOB - trigger an MOB alarm
; Any number greater than 0 - this will start a countdown timer
; that the RP4N uses for TTB calculation during a starting
sequence.
;
LONG_PRESS=5
;
;
; If you want the RP4N to turn the Nexus countdown timer on, set
; this parameter to 5 or 10. Otherwise, set it to 0;
;
; The Nexus Race Box can only start the Nexus timer counting
down
; from 5 minutes or 10 minutes. So, if you set long press
; to be a 15 minute countdown, the nexus timer will be started
; when the time reaches 10 minutes remaining if you set this
; parameter to 10. If you set it to 5, then the Nexus timer will
; be started when the RP4N timer reaches 5 minutes.
;
; If you set this parameter to a number greater than the long
; press parameter is set to, the nexus timer will never be
; started.
;
USE_NEXUS_TIMER=5
;
;
;
; If you set the RP4N timer to run longer than the Nexus timer,
; (for example, LONG_PRESS = 10 and USE_NEXUS_TIMER=5) you may
; display the time remaining on the RP4N timer in the CFD
; field.
;
; If you set the next parameter to ON then the CFD field will
; display the remaining time, but only until the Nexus countdown
; timer is started. So in this example, the CFD field will count
; down from 10:00 to 5:00 and then the CFD filed will begin
; presenting whatever data was selected below, for example,
; Time To Burn (TTB).
;
; If this parameter is set to any value other than Y, the
; time remaining on the RP4N timer will not be displayed and
; whatever data was selected below will be displayed instead.
;
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TIMER_CFD=Y
;
;
; The LINE_PERF_ONLY parameter tells the RP4N how to calculate
; distance from the start line. See the manual for full details.
; In summary, if this parameter is set to Y then distance from
; the start line will be that distance along a perpendicular
line
; from the starting line or its extensions directly to your
; bow, regardless of your boat heading.
;
LINE_PERF_ONLY=N
;
;
; Specify boat length overall in feet. You may specify a
; decimal of a foot, such as 28.5.
;
BOATLENGTH=30
;
; The number of feet aft from the bow where the GPS antenna is
; mounted. On a 30 foot boat, if the GPS antenna is on the
; very back of the stern, then this should be 30. You may
; specify a decimal of a foot, such as 22.7.
;
GPS_ANTENNA_LOCATION = 30
;
; Enter the height of the wind transducer above the surface
; of the water *in feet*. You may specify a decimal of a foot,
; such as 40.25. This number is used to correct true wind
; velocity numbers. If you have modified your polars to
; account for the transducer height, or for any other reason
; you do not want wind readings compensated for height, then
; set this parameter to 0.
;
WIND_XDUCER_HEIGHT=43
;
;
; This next parameter controls what type of data is sent to
; which field type for display on the instruments. You may
; set CAD and CFD to any one of the types listed below.
;
; Also, you may set different parameters for in a start
; sequence or out of a start sequence. "In a start sequence"
; means that you have started the RP4Ns countdown timer with a
long
; button press and the timer has not yet reached zero. Out
; of a starting sequence is any time the RP4N timer has not been
; started. If you do not use the RP4N timer, you will always
; be outside a starting sequence.
;
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; Starting the Nexus countdown timer will not start the RP4N
; timer, and therefore even if you start the Nexus timer, unless
you
; also start the RP4N timer (which starts the Nexus timer) you
; will be out of sequence. Therefore, we recommend that you
always
; use the RP4N to start the Nexus countdown timer. This will
make
; sure there is no confusion about whether or not the RP4N is
; "in starting sequence" or "out of starting sequence."
;
; Do not set CAD to TTB, since CAD can not display a negative
; number. Also, CAD only displays numbers between 0 and 359,
; so it is also a poor choice for FTL.
;
; TTL and TTB are displayed as minutes.seconds. Therefore,
; CAD is also a poor choice for TTL, as it will only display
; properly when TTL <= 3:59.
;
; You can also set a value to OPT, which will tell you
; the optimum wind angle for the current true wind
; speed. If the true wind angle is less than 90, the
; optimum up wind angle is presented. Otherwise, the
; optimum down wind angle is presented. Both of these
; values are calculated based upon the optimum values
; found in the polar table. We suggest using this
; with the CAD field.
;
; OFF - Display no data in this field
;
;
; TTL - Time to line (Only works while in starting sequence if
; a line is pinged)
;
; TTB - Time to burn (Only works while in starting sequence if
; a line is pinged)
;
; FTL - Feet to line (Works in or out of starting sequence if a
; line is pinged)
;
; BL - Boat Lengths to line (Works in or out of starting
sequence
; if a line is pinged)
;
; MTL - Meters to line (Works in or out of starting sequence if
a
; line is pinged)
;
; BIAS - line bias (Works in or out of starting sequence if a
line
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; is pinged)
;
; OPT_T - Optimum true wind sailing angle (TWA) for the current
TWS
;(Works in or out of starting sequence - line ping not needed)
;
; OPT_A - Optimum apparent wind sailing angle (AWA) for the
current
; TWS (Works in or out of starting sequence - line ping not
needed)
;
CAD_IS=BL
CFD_IS=TTB
;
CAD_OS=OPT_T
CFD_OS=OPT_A
;
;
; END OF FILE
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APPENDIX C – ERROR CODES
When things go wrong, the Race Box will flash its red error light. Different patterns of
flash represent different errors.
No SD Card Detected
If the Race Box does not have an SD card installed when it is powered up, the error
light will flash on and off very slowly.
Just insert the SD card. There is no need to power the Race Box off and on again. After
a second the card will be detected and startup will continue.
SD Card Write Protect On
This is not an error, just a notification. You need not take any action.
If the SD card has its write protect switch turned on, the red error light will flash on for
3⁄4 of a second, then off for 1⁄4 second, then on for 3⁄4 second then off for 1⁄4 second.
This pattern will repeat 6 times, then the RP4N will continue to start normally.
If the write protect switch is on, the Race Box will not write a CSV log or an NXB log,
even if it is configured to do so. It will, however, write an MOB log if the MOB function is
triggered.
No Config File Found
If the Race Box can not find its rp4n.cfg file on the SD card, it will signal a fatal error.
The red error light will flash on for 3⁄4 second, then off for 3⁄4 second. This pattern will
continue until the Race Box is powered down.
Check the SD card to make sure that the rp4n.cfg file is present in the top level
directory of the SD cards file system and that the file name is correct.
No polar Table File Found
If the RP4N is configured to use a polar table but no polar table is found on the SD
card, the red error light will flash very rapidly, going on for 150ms then off for 150ms,
repeating until the Race Box is powered down. This is a fatal error.
Make sure the polar table file ends in .nxp and is present in the top level directory of the
SD cards file system.
Failed to Establish FDX Communication
If the red error light turns on and remains on for several seconds or longer with no
flashing, this means that the RP4N failed to establish FDX communications with the
Nexus server. This is a fatal error and the RP4N will need to be restarted.
In this event, the server should also be restarted.
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APPENDIX D – POLAR FILE FORMAT
The NX2 system together with the NX2 Race SW is able to calculate target Boat Speed
from a Polar Table. The polar tables looks different for different boats.
The polar table is a tab- or comma-separated-values text file containing target
boat speeds for specific true wind angles and speeds.
Every row represents data for a specific true wind speed (except first row,
which contains the headings of the table and is ignored).
First column contains true wind speeds in knots, then, the following columns
are pairs of target boat-speeds for a specific true-wind angle.
The first and last pair of TBS-TWA columns are the best case up-wind and
down-wind, respectively, and these columns are used to compute optimum
course up- or down-wind, respectively.
NX2 Race SW interpolates and extrapolates the data to give continuous
TBS and steering course. To achieve that, the file must contain a minimum of
5 column-pairs of TBS-TWA, but no more than 20, and a minimum of 3 data lines,
but no more than 20.
So, including the column with wind speeds, the polar table should have a
total of minimum 11 columns, but not more than 41.
The format of a polar table is:
TWS
WS1
TBS1
BS11
TWA1
WA11
TBSn
BS1n
TWAn
WA1n
<-- 1st row for table headings (no data here!)
<-- 2ns row for a wind speed of WS1[kts]
WSm
BSm1
WAm1
BSmn
WAmn
<-- mth row for a wind speed of WSm[kts]
last column-pair is best case down-wind
other column-pairs TBS-TWA
first column-pair is best case up-wind
1st column contains wind speeds in [kts]
In the above representation, WS1-WSm are (m) true wind speed values in [kts],
BS11-BSmn are (m x n) target boat speed values in [kts], and WA11-WAmn are
(m x n) true wind angle values in degrees, where:
3 <= m <= 20 , and
5 <= n <= 20
Wind angles must have the same value on a given column, excepting the first
and the last wind-angle columns, which are a special optimum case.
There must be no empty rows in the file, except for one row at the beginning
(the heading row), which is ignored (and therefore put no values in there).
All values must be separated with either tabs or commas (not spaces) and all
rows must contain the same number of values (i.e. if row2 has 13 values, all
other rows should have the same number of values).
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7 Specifications
7.1
Technical specifications Compss Instrument
Dimensions:
156 x 156 32 mm (4.3x4.3 inch).
Power supply:
Power
consumption at 12V:
12V DC (10-16V). The instruments are polarity protected
Temperature range:
Storage: -30°to +80°C (-22°to +176°F)
Operation: -10° to +70°C(14°to +158°F)
RaceBox: 230 gram (9.17 oz).
Weight:
Instrument: 0,12W
.
CE approval
The products conforms to the EMC requirements for immunity and
emission according to EN 50 08-1.
FCC approval
This device complies with part 15 of the FCC Rules
Operation is subject to the following two conditions:
(1) This device may not cause harmful interference, and
(2) this device must accept any interference received, including interference that may
cause undesired operation.
The user may not change or make modifications not expressly approved by the party
responsible for this compliance.
8 Warranty
The warranty period for these products is 2 years for instruments
and transducers. For consumables as batteries o-rings etc. the
warranty period is 6 months. For the complete warranty
conditions, see next page.
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Copyright ©:
Nexus Marine AB
Karlsbodavägen 20B, 168 67 Bromma, Sweden
Tel: +46 -(0) 8 – 506 939 00. Fax: +46 -(0) 8 -506 939 01
www.nexusmarine.se
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