Vaisala WXT510 User manual

Weather Transmitter
WXT510
USER'S GUIDE
M210470EN-B
January 2005

PUBLISHED BY
Vaisala Oyj Phone (int.): [phone]
P.O. Box 26 Fax: [phone]
FIN-00421 Helsinki
Finland
Visit our Internet pages at http://www.vaisala.com/
© Vaisala 2005
No part of this manual may be reproduced in any form or by any means,
electronic or mechanical (including photocopying), nor may its contents be
communicated to a third party without prior written permission of the copyright
holder.
The contents are subject to change without prior notice.
Please observe that this manual does not create any legally binding obligations for
Vaisala towards the customer or end user. All legally binding commitments and
agreements are included exclusively in the applicable supply contract or
Conditions of Sale.

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Table of Contents
CHAPTER 1
GENERAL INFORMATION............................................................................ 7
Feedback............................................................................... 7
Safety......................................................................................... 7
Trademarks ............................................................................... 9
License Agreement .................................................................. 9
Warranty .................................................................................... 9
CHAPTER 2
PRODUCT OVERVIEW................................................................................ 10
Weather Transmitter WXT510 ............................................... 10
Optional software for easy settings ..................................... 10
Heating function .................................................................. 10
WXT510 Transmitter components ........................................ 11
CHAPTER 3
FUNCTIONAL DESCRIPTION..................................................................... 12
Wind measurement principle ................................................ 12
Precipitation measurement principle ................................... 13
PTU measurement principle.................................................. 14
Heating (Optional) .................................................................. 14
CHAPTER 4
INSTALLATION............................................................................................ 16
Unpacking instructions ......................................................... 16
Selecting location................................................................... 16
Assembling the WXT510........................................................ 17
Installation Procedure............................................................ 17
Mounting.............................................................................. 17
Mounting to a vertical pole mast .................................... 18
Mounting with a mounting kit (optional) ......................... 18
Mounting to a horizontal cross arm................................ 19
Aligning the WXT510 .......................................................... 20
Compass Alignment ....................................................... 20
Wind direction correction................................................ 21
CHAPTER 5
WIRING......................................................................................................... 22
Power supplies ....................................................................... 22
Wiring by using the screw terminals.................................... 24
Wiring by using the 8-pin M12 connector (optional) .......... 25
External wiring..................................................................... 25
Internal wiring ...................................................................... 26

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Data communication interfaces ............................................27
CHAPTER 6
COMMUNICATION SETTINGS....................................................................28
Communication protocols .....................................................28
Service cable connection ......................................................29
Communication setting commands......................................30
Checking the current communication settings (aXU) ..........30
Setting fields ........................................................................30
Changing the communication settings ................................32
CHAPTER 7
GETTING THE DATA MESSAGES..............................................................34
General Commands................................................................34
Reset (aXZ) .........................................................................34
Precipitation counter reset (aXZRU) ...................................35
Measurement reset (aXZM).................................................36
ASCII protocol, polled (without CRC)...................................37
Abbreviations and units .......................................................37
Device address (?) ..............................................................38
Acknowledge active command (a) ......................................38
Wind data message (aR1)...................................................39
Pressure, temperature and humidity data message (aR2) .39
Precipitation data message (aR3) .......................................40
Supervisor data message (aR5)..........................................41
Combined data message (aR) ............................................42
Composite data message query (aR0)................................42
ASCII protocol, polled (with CRC) .......................................43
ASCII protocol, automatic....................................................45
SDI-12 protocol .......................................................................45
Acknowledge active command (a) ......................................45
Send identification command (aI)........................................46
Address query command (?) ...............................................47
Change address command (aAb) .......................................47
Start measurement command (aM).....................................48
Start concurrent measurement (aC)....................................50
Send data command (aD) ...................................................51
Examples of aM, aC and aD commands:............................52
Continuous measurement (aRx) .........................................54
Continuous measurement with CRC (aRC) ........................55
Start verification command (aV) ..........................................55
NMEA 0183 V3.0 protocol ......................................................56
Device address (?) ..............................................................56
Acknowledge active command (a) ......................................56
MWV wind speed and direction query.................................57
XDR transducer measurement query..................................58
TXT text transmission..........................................................65
NMEA 0183 v3.0, Automatic ...............................................65
CHAPTER 8
SENSOR AND DATA MESSAGE SETTINGS ............................................. 66
Wind sensor ............................................................................66
Checking the settings ..........................................................66

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Setting fields........................................................................ 67
Changing the settings ......................................................... 68
Pressure, temperature and humidity sensors..................... 70
Checking the settings .......................................................... 70
Setting fields........................................................................ 71
Changing the settings ......................................................... 71
Precipitation sensor............................................................... 73
Checking the settings .......................................................... 73
Setting fields........................................................................ 74
Changing the settings ......................................................... 75
Supervisor message .............................................................. 77
Checking the settings .......................................................... 77
Setting fields........................................................................ 77
Changing the settings ......................................................... 79
Composite message .............................................................. 80
CHAPTER 9
MAINTENANCE ........................................................................................... 81
Cleaning .................................................................................. 81
Replacing the PTU module.................................................... 81
Factory calibration and repair service ................................. 82
Vaisala Service Centers......................................................... 82
CHAPTER 10
TROUBLESHOOTING ................................................................................. 83
Self-diagnostics...................................................................... 85
Error messaging/Text messages ........................................ 85
Rain and wind sensor heating control................................. 86
Operating voltage control .................................................... 86
Technical Support .................................................................. 86
CHAPTER 11
TECHNICAL SPECIFICATIONS.................................................................. 87
Performance ........................................................................... 87
Inputs and outputs ................................................................. 89
Operation conditions ............................................................. 90
Materials .................................................................................. 90
General .................................................................................... 90
Options and Accessories ...................................................... 91
Dimensions in mm [inches]................................................... 92
APPENDIX A
NETWORKING ............................................................................................. 93
Connecting several WXT510s on the same bus.................. 93
SDI-12 serial interface............................................................ 93
Wiring .................................................................................. 93
Communication protocol ..................................................... 93
RS-485 serial interface........................................................... 94
Wiring .................................................................................. 94

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Communication protocol......................................................94
ASCII, polled........................................................................94
NMEA 0183 v3.0, query ......................................................95
NMEA 0183 v3.0 query with ASCII query commands.........97
APPENDIX B
SDI-12 PROTOCOL......................................................................................99
SDI-12 Electrical Interface...................................................99
SDI-12 Communications Protocol .......................................99
SDI-12 Timing....................................................................100
APPENDIX C
CRC-16 COMPUTATION ...........................................................................102
Encoding the CRC as ASCII Characters.............................102
NMEA 0183 v3.0 Checksum computation ..........................103

Chapter 1 _________________________________________________________ General Information
VAISALA_________________________________________________________________________ 7
CHAPTER 1
GENERAL INFORMATION
Feedback
Vaisala Customer Documentation Team welcomes your comments
and suggestions on the quality and usefulness of this publication. If
you find errors or have other suggestions for improvement, please
indicate the chapter, section, and page number. You can send
comments to us by e-mail: [email protected]
Safety
General Safety Considerations
Throughout the manual, important safety considerations are
highlighted as follows:
WARNING Warning alerts you to a serious hazard. If you do not read and follow
instructions very carefully at this point, there is a risk of injury or
even death.
CAUTION Caution warns you of a potential hazard. If you do not read and
follow instructions carefully at this point, the product could be
damaged or important data could be lost.
NOTE Note highlights important information on using the product.

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Product Related Safety Precautions
The WXT510 delivered to you has been tested for safety and
approved as shipped from the factory. Note the following precautions:
WARNING Ground the product, and verify outdoor installation grounding
periodically to minimize shock hazard.
CAUTION Do not modify the unit. Improper modification can damage the
product or lead to malfunction.
ESD Protection
Electrostatic Discharge (ESD) can cause immediate or latent damage
to electronic circuits. Vaisala products are adequately protected
against ESD for their intended use. However, it is possible to damage
the product by delivering electrostatic discharges when touching,
removing, or inserting any objects inside the equipment housing.
To make sure you are not delivering high static voltages yourself:
- Handle ESD sensitive components on a properly grounded and
protected ESD workbench. When this is not possible, ground
yourself to the equipment chassis before touching the boards.
Ground yourself with a wrist strap and a resistive connection cord.
When neither of the above is possible, touch a conductive part of
the equipment chassis with your other hand before touching the
boards.
- Always hold the boards by the edges and avoid touching the
component contacts.

Chapter 1 _________________________________________________________ General Information
VAISALA_________________________________________________________________________ 9
Trademarks
WINDCAP, RAINCAP, HUMICAP, BAROCAPand
THERMOCAPare registered trademarks of Vaisala. Microsoft,
Windows, and Windows NTare registered trademarks of
Microsoft Corporation in the United States and/or other countries.
License Agreement
All rights to any software are held by Vaisala or third parties. The
customer is allowed to use the software only to the extent that is
provided by the applicable supply contract or Software License
Agreement.
Warranty
For certain products Vaisala normally gives a limited one-year
warranty. Please observe that any such warranty may not be valid in
case of damage due to normal wear and tear, exceptional operating
conditions, negligent handling or installation, or unauthorized
modifications. Please see the applicable supply contract or Conditions
of Sale for details of the warranty for each product.

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CHAPTER 2
PRODUCT OVERVIEW
Weather Transmitter WXT510
Weather Transmitter WXT510 is a small and lightweight transmitter
that offers six weather parameters in one compact package. WXT510
measures wind speed and direction, precipitation, atmospheric
pressure, temperature and relative humidity.
WXT510 powers up with 5...30 VDC and outputs serial data with a
selectable communication protocol: SDI-12, ASCII automatic &
polled and NMEA 0183 with query option. Four alternative serial
interfaces are selectable: RS-232, RS-485, RS-422 and SDI-12.
The following options are available:
-Windows® based WXT Configuration Tool software and cable
-Heating function for the precipitation and wind sensors
-8-pin M12 connector (also with 2 m/10 m cable)
-Mounting kit
Optional software for easy settings
Windows® based WXT Configuration Tool is a user friendly
parameter setting software for WXT510. With this software tool you
can change the device and sensor settings easily in Windows®
environment. See list of options and accessories on page 91.
Heating function
To improve the accuracy of measurements an optional heating for the
wind and precipitation sensors is available. More about heating on
page 14.
The heating function option must be chosen when placing the order.

Chapter 2 ___________________________________________________________ Product Overview
VAISALA________________________________________________________________________ 11
WXT510 Transmitter components
Bottom of the transmitter
Mounting kit (optional)
Service cable (optional)
forces the serial port to RS-232 / 19200,8,N,1
Wind transducers
Precipitation senso
r
Pressure senso
r
module
Humidity/temperature
sensor
Radiation
shield
Service port
Cable gland
(water tight)
Opening for wires (i
f
unused, cover with
hexagonal plugs)
8-pin M12 connector fo
r
power/signal cable
(optional)
Alignment
direction
si
g
n
Bottom of the
transmitter
Top of the
transmitter
Screw cove
r
Radiation shield

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CHAPTER 3
FUNCTIONAL DESCRIPTION
Wind measurement principle
The WXT510 uses Vaisala WINDCAPsensor technology in wind
measurement.
The wind sensor has an array of three equally spaced ultrasonic
transducers on a horizontal plane. Wind speed and wind directions are
determined by measuring the time it takes the ultrasound to travel
from each transducer to the other two.
The wind sensor measures the transit time (in both directions) along
the three paths established by the array of transducers. This transit
time depends on the wind speed along the ultrasonic path. For zero
wind speed, both the forward and reverse transit times are the same.
With wind along the sound path, the up-wind direction transit time
increases and the down-wind transit time decreases.
The wind speed is calculated from the measured transit times using
the following formula:
)/1/1(5.0 rfw ttLV −××=
where:
Vw= Wind speed
L = Distance between the two transducers
tf= Transit time in forward direction
tr= Transit time in reverse direction
Measuring the six transit times allows Vwto be computed for each of
the three ultrasonic paths. The computed wind speeds are independent
of altitude, temperature and humidity, which are cancelled out when
the transit times are measured in both directions, although the
individual transit times depend on these parameters.

Chapter 3 _______________________________________________________ Functional Description
VAISALA________________________________________________________________________ 13
Using Vwvalues of two array paths is enough to compute wind speed
and wind direction. A signal processing technique is used so that wind
speed and wind direction are calculated from the two array paths of
best quality.
The wind speed is represented as a scalar speed in selected units (m/s,
kt, mph, km/h). The wind direction is expressed in degrees (°). The
wind direction reported by WXT510 indicates the direction that the
wind comes from. North is represented as 0°, east as 90°, south as
180°, and west as 270°.
The wind direction is not calculated when the wind speed drops below
0.05 m/s. In this case, the last calculated direction output remains until
the wind speed increases again to the level of 0.05 m/s.
Wind speed and direction average values are calculated as a scalar
average of 250 ms samples over the configurable averaging time
(1...3600s). Wind speed and direction minimum and maximum values
are the absolute minimum and maximum values of the 250 ms
samples during the averaging time.
Precipitation measurement principle
The WXT510 uses Vaisala RAINCAPsensor 2 technology in
precipitation measurement.
The precipitation sensor comprises of a steel cover and a
piezoelectrical sensor mounted on the bottom surface of the cover.
The precipitation sensor detects the impact of individual raindrops.
The signals from the impact are proportional to the volume of the
drops. Hence, the signal of each drop can be converted directly to
accumulated rainfall. Advanced noise filtering technique is used to
filter out signals originating from other sources than raindrops.
The measured parameters are accumulated rainfall, rain intensity, and
the duration of a rain. Detection of each individual drop enables
computing of rain amount and intensity with high resolution. The
precipitation intensity represents the intensity during the one minute
period minute just before automatic precipitation message sending/
polling. This period is fixed.The intensity value is internally updated
every 10 seconds.
The sensor is also capable of distinguishing hails from raindrops. The
measured hail parameters are cumulative amount of hails, hail
intensity, and the duration of a hail shower.
The precipitation sensor operates in the following four modes:

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-Precipitation Start/End mode:
Transmitter sends automatically a precipitation message 10 seconds
after the recognition of the first drop. The messages are sent
continuously as the precipitation proceeds and stopped when the
precipitation ends.
-Tipping bucket mode:
This mode emulates tipping bucket type precipitation sensors.
Transmitter sends automatically a precipitation message when the
counter detects one unit increment (0.1 mm/0.01 in).
-Time mode:
Transmitter sends automatically a precipitation message in the
update intervals defined by the user.
-Polled mode:
Transmitter sends a precipitation message whenever requested by
the user.
More information about the precipitation sensor operation modes is
found on page 73.
PTU measurement principle
PTU module contains separate sensors for pressure, temperature, and
humidity measurement.
The measurement principle of the pressure, temperature, and humidity
sensors is based on an advanced RC oscillator and two reference
capacitors against which the capacitance of the sensors is continuously
measured. The microprocessor of the transmitter performs
compensation for the temperature dependency of the pressure and
humidity sensors.
PTU module includes
-capacitive silicon BAROCAP®sensor for pressure measurement
-capacitive ceramic THERMOCAP®sensor for air temperature
measurement and
-capacitive thin film polymer HUMICAP®180 sensor for humidity
measurement.
Heating (Optional)
The heating function keeps the wind and precipitation sensor clean
from snow and ice. The heaters are located below the precipitation

Chapter 3 _______________________________________________________ Functional Description
VAISALA________________________________________________________________________ 15
sensor and inside the wind transducers. A temperature sensor
underneath the precipitation sensor monitors the need for heating.
The three fixed temperature limits control the heating power as
follows:
-temperature (Th) > +3 °C: heating is off
--2 °C < temperature (Th) < +3 °C: 50 % heating power
--4 °C < temperature (Th) < -2 °C: 100 % heating power
-temperature (Th) < -4 °C: 50 % heating power
When the heating function is disabled the heating is off in all
conditions, see the Supervisor message, see page 77 .
High limit (+ 3 °
°°
°C/ 37.4 °
°°
°F)
Middle limit (-2 °
°°
°C /28.4 °
°°
°F)
Low limit (-4 °
°°
°C/ 24.8 °
°°
°F)

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CHAPTER 4
INSTALLATION
Unpacking instructions
Weather Transmitter WXT510 comes in a custom shipping container.
Be careful when removing the device from the container.
CAUTION Beware of damaging any of the wind transducers located at the top of
the three antennas. Dropping the device can break or damage the
transducers. If the antenna bends or twists the re-aligning can be
difficult or impossible.
Selecting location
Finding a suitable site for Weather Transmitter WXT510 is important
for getting representative ambient measurements. The site should
represent the general area of interest.
Weather Transmitter WXT510 should be installed in a location that is
free from turbulence caused by nearby objects, such as trees or
buildings.
WARNING To protect personnel (and the device), a lightning rod should be
installed with the tip at least one meter above the WXT510. The rod
must be properly grounded, compliant with all local applicable safety
regulations.

Chapter 4 ________________________________________________________________ Installation
VAISALA________________________________________________________________________ 17
Assembling the WXT510
1. Turn out the top of the transmitter.
2. Remove the protective cap.
3. Replace the top and tighten the three fixing screws that fasten the
top and the bottom.
Installation Procedure
At the measurement site, WXT510 needs to be mounted, aligned, and
connected to the data logger and the power source.
Mounting
Weather Transmitter WXT510 can be mounted either onto a vertical
pole mast or onto a horizontal cross arm. When mounting WXT510
onto a pole mast, an optional mounting kit can be used to ease
mounting. When using the optional mounting kit, alignment is needed
only when mounted for the first time.
Top of the transmitte
r
Protective cap
Fixing screw
(3 pcs)

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18 ___________________________________________________________________ M210470EN-B
Each of the mounting options is further described in the following
sections.
NOTE Weather Transmitter WXT510 must be installed to an upright,
vertical position.
Mounting to a vertical pole mast
1. Remove the screw cover and insert the WXT510 to the pole mast.
2. Align the transmitter in such a way that the arrow points to north,
see page 20.
3. Tighten the fixing screw and replace the screw cover.
Mounting with a mounting kit (optional)
1. Insert the mounting kit adapter to the transmitter bottom in the
position shown in the picture.
2. Turn the kit inside the bottom firmly until you feel that the adapter
snaps into the locked position (see picture in the next page).
3. Mount the adapter to the pole mast (do not tighten the fixing
screw).
4. Align the transmitter in such a way that the arrow points to north,
see page 20.
5. Tighten the fixing screw to fix the adapter firmly to the pole mast.
NOTE When removing the WXT510 from the pole just turn the transmitter
so that it snaps out from the mounting kit. When replacing the device
the alignment is not needed.
Fixing
screw
(provided)

Chapter 4 ________________________________________________________________ Installation
VAISALA________________________________________________________________________ 19
Mounting to a horizontal cross arm
1. Remove the screw cover.
2. Align the horizontal cross arm in south-north-direction, see page
20.
In case the cross arm cannot be aligned, make the wind direction
correction as instructed on page 21.
3. Mount the transmitter into the cross arm by using the fixing screw
(M6 DIN933) and a nut, see picture.
Nut
Fixing screw
(M6 DIN933)
Mounting kit
(optional)
Insert the mounting adapter.
Fixing screw
(provided)
Pole mast
Turn firmly until adapter is
locked.
North
22
M6 DIN933 A4 Cross arm

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Aligning the WXT510
To help the alignment, there is an arrow and the text North on the
bottom of the transmitter. WXT510 should be aligned in such a way
that this arrow points to the north.
Wind direction can be referred either the true north, which uses the
earth's geographic meridians, or to the magnetic north, which is read
with a magnetic compass. The magnetic declination is the difference
in degrees between the true north and magnetic north.
0003-011
Sketch of Magnetic Declination
NOTE The source for the magnetic declination must be current as the
declination changes over time.
Compass Alignment
To align Weather Transmitter WXT510, proceed as follows:
1. If the WXT510 is already mounted, loosen the fixing screw on the
bottom of the transmitter so that you can rotate the device.
2. Use a compass to determine that the transducer heads of WXT510
are exactly in line with the compass and that the arrow on the
bottom of WXT510 points to the north.