Airmar 300WXR, 300WX, 150WX, 100WX w/CAN,100WX User manual

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WX Series WeatherStation Technical Manual
(Derivative Products Include 300WXR, 300WX, 150WX, 100WX w/CAN,
100WX)
Revision 1.000
05/11/11
- DRAFT -
This document is PRELIMINARY and Subject to Change.
AIRMAR Technology Corporation
35 Meadowbrook Drive
Milford, NH 03055-4613
[phone]
PROPRIETARY AND CONFIDENTIAL
THIS DOCUMENT AND THE DATA DISCLOSED HEREIN OR
HEREWITH IS NOT TO BE REPRODUCED, USED, OR DISCLOSED
IN WHOLE OR IN PART TO ANYONE WITHOUT THE
PERMISSION OF AIRMAR TECHNOLOGY CORPORATION.

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Table of Contents
1.Introduction 4
1.NMEA 0183 Interfaces 5
1.1.Transmitted NMEA 0183 Sentences .................................................................. 5
$GPDTM............................................................................................................. 9
$GPGGA........................................................................................................... 11
$GPGLL............................................................................................................ 13
$GPGSA ........................................................................................................... 14
$GPGSV ........................................................................................................... 15
$HCHDG .......................................................................................................... 17
$HCHDT........................................................................................................... 18
$WIMDA.......................................................................................................... 19
$WIMWD ......................................................................................................... 21
$WIMWV ......................................................................................................... 22
$GPRMC........................................................................................................... 23
$TIROT............................................................................................................. 24
$HCTHS ........................................................................................................... 25
$GPVTG ........................................................................................................... 26
$WIVWR.......................................................................................................... 27
$WIVWT .......................................................................................................... 28
$--XDR ............................................................................................................. 29
$YXXDR-A...................................................................................................... 30
$YXXDR-B ...................................................................................................... 32
$YXXDR-C ...................................................................................................... 33
$YXXDR-D...................................................................................................... 34
$YXXDR-E....................................................................................................... 35
$YXXDR-H...................................................................................................... 36
$WIXDR-R....................................................................................................... 37
$YXXDR-T....................................................................................................... 38
$WIXDR-W...................................................................................................... 39
$GPZDA ........................................................................................................... 40
$PAMTO........................................................................................................... 41
$PAMTOC........................................................................................................ 42
$PAMTRW....................................................................................................... 43
$PAMTW.......................................................................................................... 44
1.2.Received NMEA 0183 Sentences and Commands........................................... 45
$--VHW ............................................................................................................ 47
$PAMTC........................................................................................................... 48
$PAMTC,ALT.................................................................................................. 49
$PAMTC,ATTOFF........................................................................................... 51
$PAMTC,BAUD .............................................................................................. 54
$PAMTC,COMP .............................................................................................. 55
$PAMTC,DATUM........................................................................................... 63
$PAMTC,EN .................................................................................................... 65

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$PAMTC,ERST................................................................................................ 71
$PAMTC,HEATER.......................................................................................... 72
$PAMTC,LAMP............................................................................................... 74
$PAMTC,OPTION........................................................................................... 75
$PAMTC,POST................................................................................................ 79
$PAMTC,QPS .................................................................................................. 81
$PAMTC,QV.................................................................................................... 82
$PAMTC,RESET.............................................................................................. 83
$PAMTC,RESET,GPS ..................................................................................... 84
$PAMTC,RESET,RAIN,RAIN........................................................................ 85
$PAMTC,RESET,RAIN,RATE ....................................................................... 85
$PAMTC,SIM................................................................................................... 86
$PAMTC,WIND............................................................................................... 87
$PAMTX........................................................................................................... 89
2.Revision History 90

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1. Introduction
The WX Series of WeatherStation Sensors are a family of multifunctional devices that
integrates several sensors into a single compact housing. These sensors include some of
the following depending on the configuration:
•Ultrasonic anemometer, providing apparent wind speed and direction
•Thermistor, providing air temperature
•Piezoresistive pressure sensor, providing barometric pressure
•Capacitive humidity sensor, providing relative humidity
•Magnetoinductive XYZ sensors, providing tilt-compensated magnetic compass
heading (3D compass)
•3-axis MEMS1accelerometer, providing pitch and roll angles
•MEMS rate gyro, providing rate-of-turn , pitch rate, and roll rate of the vessel
•Global Positioning System (GPS) receiver with 10 Hz update rate, providing
position, and speed and course over ground
•Polyvinylidene fluoride (PVDF) rain sensor, providing rain rate and accumulated
rain measurements
•Thermistor providing the operating temperature of the main processor board
•Voltage sensor providing the board/network voltage
In addition to the above directly measured parameters, the WX Series WeatherStation
Sensor is able to calculate the following values as well, if the necessary data are
available:
•True wind speed and direction
•Heading relative to true north
•Apparent wind chill temperature
•True wind chill temperature
•True wind speed relative to water (with optional Airmar® Smart™ speed sensor,
not included)
1MEMS is an acronym for Micro Electro-Mechanical Systems

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The WX Series WeatherStation Sensor has one communication interfaces with the
NMEA 0183 protocol.
This document provides detailed descriptions of the communications protocols for the
NMEA 0183 interface used by the WX Series WeatherStation Sensor.
For further information about the NMEA 0183 protocol, refer to the document, NMEA
0183 Standard for Interfacing Marine Electronic Devices, v4.00. This document is
available from the National Marine Electronics Association (www.nmea.org).
1. NMEA 0183 Interfaces
The Airmar WX Series WeatherStation Sensor may have a single standard NMEA 0183-
compliant output channel, and a single standard NMEA 0183-compliant input channel. If
so, the unit transmits standard NMEA 0183 sentences on its output channel. It also
recognizes standard and proprietary NMEA 0183 sentences received on its input channel.
The standard baud rate for both input and output channels is 4800 baud, though if desired
this may be increased to 38400 baud via a proprietary command.1
The transmitted NMEA 0183 sentences are described in section 1.1. Received NMEA
0183 sentences and proprietary commands are described in section
1.1. Transmitted NMEA 0183 Sentences
By default, only certain NMEA sentences are enabled for transmission. Other sentences
may be enabled individually for transmission via commands sent to the input channel.2
The standard transmission interval for most of the transmitted sentences is once per
second. However, in models that include an integrated GPS, if every sentence were
enabled for transmission, there would not be enough bandwidth in the output channel at
4800 baud to output all sentences within a one second timeframe. Therefore, one or more
of the following remedies should be employed:
•To conserve bandwidth, only enable for transmission those sentences required for
the given application, and disable all others.
•Reduce the frequency of transmission for less critical sentences.
•Increase the overall bandwidth eightfold by increasing the baud rate from the
standard 4800 baud to 38400 baud (though keep in mind that most NMEA 0183
instruments are not capable of operating at 38400 baud)
All NMEA sentences transmitted by the WX Series WeatherStation Sensor include a
checksum at the end of the sentence, consisting of an asterisk (*) followed by two ASCII
1See the $PAMTC,BAUD command.
2See the $PAMTC,EN command.

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hexadecimal characters. In the detailed specifications to follow, these hexadecimal
characters are designated by “hh”.
The standard NMEA 0183 sentences provided by the WX Series WeatherStation Sensor
are summarized in Table 1. Each of the transmitted sentences in Table 1 is described in
detail on the subsequent pages.
The Maximum Length (chars) column in the table indicates an expected worst-case
scenario that can be used for bandwidth budgeting. The total time in seconds required to
transmit all enabled sentences in a single interval is
ratebaud
charactersofnumberTotal
timeontransmissiTotal _
10___
__
×
=

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Table 1: NMEA 0183 Regularly Transmitted Sentences
Sentence Description Enabled
by
Default
Maximum
Length
(chars)
WXR300
$GPDTM Datum Reference No 47 


$GPGGA GPS Fix Data 

82 


$GPGLL Geographic Position –
Latitude/Longitude No 48 


$GPGSA GNSS DOP and Active Satellites No 66 


$GPGSV GNSS Satellites in View No 70 


$HCHDG Heading, Deviation and Variation No 33 


$HCHDT Heading relative to True North No 19 


$WIMDA Meteorological Composite.
Barometric pressure, air temperature,
relative humidity, dew point, wind
direction, wind speed


81



$WIMWD Wind Direction and Speed, with
respect to north1


41 


$WIMWV
(relative) Wind Speed and Angle, in relation to the vessel’s bow/centerline (relative)


28 


$WIMWV
(theoretical) Wind Speed and Angle, in relation to the vessel’s bow/centerline
(theoretical) 1


28



$GPRMC Recommended Minimum Specific
GNSS Data No 74 


$TIROT Rate of Turn 

22 


$HCTHS True Heading and Status No 19 


$GPVTG Course Over Ground and Ground
Speed


42 


$WIVWR Relative Wind Speed and Angle No 41 


$WIVWT True Wind Speed and Angle 

241 


1True wind data is provided in the $WIMWD and $WIMWV (theoretical) sentences if SOG/COG,
heading, and magnetic variation data are available from the internal GPS and compass.
2$WIVWT True Wind Speed and Angle referenced to water is provided only if water referenced speed is
available via the NMEA 0183 input or from the NMEA 2000® bus from an Airmar® Smart™ speed
sensor.

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Sentence Description Enabled
by
Default
Maximum
Length
(chars)
WXR300
$YXXDR
(type A) Transducer Measurements: wind chill, heat index, and station pressure No 74



$YXXDR
(type B) Transducer Measurements: vessel attitude (pitch and roll) No 43



$YXXDR
(type C) Transducer Measurements:
Accelerometers
No ?



$YXXDR
(type D) Transducer Measurements: Rate gyros: Pitch, Roll, Yaw No ?



$YXXDR
(type E) Transducer Measurements: Rate gyros: Pitch, Roll, Yaw (Raw) No ?



$YXXDR
(type H) Transducer Measurements: Heater temperatures and voltages No ?



$WIXDR
(type R) Transducer Measurements: rain No ?



$YXXDR
(type T) Transducer Measurements: Internal temperatures and voltages No ?



$WIXDR
(type W) Transducer Measurements: Raw wind phase values No ?



$GPZDA Time and Date 

38




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NMEA 0183 TRANSMITTED SENTENCE
$GPDTM
$PAMTC,EN: DTM Default Interval (m:ss.00) 0:1.00 Enabled By Default: No
Summary
NMEA 0183 standard Datum Reference.
Syntax
$GPDTM,<1>,<2>,<3>,<4>,<5>,<6>,<7>,<8>*hh<CR><LF>
Fields
<1> Three character alphabetical code for local datum:
W84 (WGS84)
W72 (WGS72)
S85 (SGS85)
P90 (PE90)
or IHO datum code from the International Hydrographic
Organization Publication S-60 Appendices B and C.
<2> One character subdivision datum code when available, as defined in
IHO Publication S-60 Appendices B and C.
<3> Latitude offset, to the nearest .0001 minute
<4> N if field <3> is North Latitude
S if field <3> is South Latitude
<5> Longitude offset, to the nearest .0001 minute
<6> E if field <5> is East Longitude
W if field <5> is West Longitude
<7> Signed altitude offset, to the nearest meter
<8> 3-character reference datum code:
W84 = WGS-84
Notes Latitude and longitude offsets are positive numbers; the altitude offset may be
negative. Offsets change with position; position in the local datum is offset from
the position in the reference datum in the directions indicated:
Plocal datum = Pref datum + offset
KGS, OHI-A, OHI-B, OHI-C, OHI-D, OHI-M, SIR, P90, and S85 are not
currently supported by the GPS Engine used in the the WX Series WeatherStation
Sensor, and therefore are not available for use as Local Datum.

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See also the proprietary NMEA 0183 command $PAMTC,DATUM.