Vaisala WINDCAP WS425 Ultrasonic Wind Sensor User's Guide
Below you will find brief information for Ultrasonic Wind Sensor WINDCAP WS425. This user guide covers the installation, operation, and maintenance of the WS425 Ultrasonic Wind Sensor. The sensor is equipped with an on-board microcontroller that captures and processes data and performs serial communications. The sensor has an array of three equally spaced ultrasonic transducers on a horizontal plane. The user guide provides step-by-step instructions to install and operate the sensor in various modes, including analog, SDI-12, and serial RS-232/422/485.
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USER'S GUIDE
Vaisala WINDCAP® Ultrasonic Wind Sensor
WS425
M210361EN-E
PUBLISHED BY
Vaisala Oyj
P.O. Box 26
FI-00421 Helsinki
Finland
Phone (int.): +358 9 8949 1
Fax:
Visit our Internet pages at http://www.vaisala.com/
+358 9 8949 2227
© Vaisala 2010
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.
________________________________________________________________________________
Table of Contents
CHAPTER 1
GENERAL INFORMATION ............................................................................ 7
About This Manual ................................................................... 7
Contents of This Manual ....................................................... 7
Version Information ............................................................... 8
Feedback............................................................................... 8
Safety....................................................................................... 10
General Safety Considerations ........................................... 10
Product Related Safety Precautions ................................... 10
Inverted Mounting .......................................................... 10
Absolute Maximum Voltages ......................................... 10
ESD Protection.................................................................... 11
Regulatory Compliances ....................................................... 12
EN55011 Class A Group 1 & EN50082-2 ........................... 12
MIL-STD-426 Method RS03................................................ 12
MIL-STD 810 Method 501 Process 1.................................. 12
MIL-STD 202 Method 213................................................... 12
MIL-STD-167-1 (SHIPS) ..................................................... 12
Third-Party Testing (Field Tests Included).......................... 13
NWS ASOS Mechanical Wind Sensor Replacement .... 13
Lawrence Livermore Labs.............................................. 13
Tennessee Valley Authority ........................................... 13
CETIAT (Centre Technique des Industries Aéraulique et
Thermiques) ................................................................... 13
Trademarks ............................................................................. 14
License Agreement ................................................................ 14
Warranty .................................................................................. 14
CHAPTER 2
PRODUCT OVERVIEW................................................................................ 15
Introduction to WS425 ........................................................... 15
Measuring Principle............................................................. 15
Sensor Operating Modes .................................................... 16
Sensor Features ..................................................................... 17
Polar Wind Speed and Direction ......................................... 18
Wind Speed X and Y Components ..................................... 18
Scalar Averaging of Wind Speed and Direction.................. 18
Vector Averaging of Wind Speed and Direction.................. 19
Wind Direction Coasting...................................................... 19
Gust Wind Speed and Direction Over Time........................ 20
CHAPTER 3
Selecting Location ................................................................. 21
Installation Procedure............................................................ 21
Unpacking Instructions........................................................ 21
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USER'S GUIDE____________________________________________________________________
Factory Settings...................................................................22
RS-232 Default Settings for USA ...................................22
Default Settings of RS-232, RS-422, and RS-485 for
Europe ............................................................................23
Mounting..............................................................................26
Mounting Procedure on a 1-inch IPS Vertical Pipe........26
Inverted Mounting...........................................................26
Alignment.............................................................................27
Magnetic Declination Correction ....................................27
Compass Alignment with a Mast Adapter ......................28
Connections ............................................................................31
Powering..................................................................................33
Power Supplies....................................................................33
CHAPTER 4
Analog Mode ...........................................................................35
Wind Speed .........................................................................35
Wind Direction .....................................................................37
Missing Readings ................................................................37
Serial Mode..............................................................................38
Overview..............................................................................38
Serial Mode Default Settings for the USA ......................38
Serial Mode Default Settings for Europe........................39
Configuration Menu .............................................................39
Configuration Commands....................................................40
Handar RS-232 ..............................................................41
Identify Command I ........................................................41
Measurement Command Wx .........................................41
Missing Readings ......................................................42
Measurement Unit Change Command Ux .....................43
NMEA Standard .............................................................43
Missing Readings ......................................................44
NMEA Extended Message .............................................44
WAT11 Message............................................................46
Missing Readings ......................................................46
Wind Speed Units................................................................47
Average Interval ..................................................................47
Averaging Method ..........................................................47
Scalar Averaging .......................................................47
Vector Averaging.......................................................48
Output Interval .....................................................................48
Sensor ID Character............................................................48
Wind Direction Coast Threshold..........................................49
Head Orientation .................................................................49
Bit Rate................................................................................49
Parity ...................................................................................50
Data Bits ..............................................................................50
Save Configuration ..............................................................50
Zero Speed Calibration .......................................................50
Resume Operation ..............................................................51
SDI-12 Protocol .......................................................................51
SDI-12 Support Group.........................................................51
SDI-12 Electrical Interface...................................................51
Serial Data Line ...................................................................52
Voltage Transitions..............................................................52
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________________________________________________________________________________
Impedance........................................................................... 52
SDI-12 Communications Protocol ....................................... 53
Baud Rate and Byte Frame Format .................................... 53
Two Different Submodes..................................................... 54
Standard SDI-12 Commands Supported by WS425 .......... 55
Acknowledge Active Command (a!)............................... 55
Send Identification Command (aI!) ................................ 56
Address Query Command (?!) ....................................... 56
Change Address Command (aAb!)................................ 57
Start Measurement Command (aM!) ............................. 58
Send Data Command (aD0!) ......................................... 58
Continuous Measurements (aR0!) ................................. 60
Start Verification (aV!) .................................................... 61
Vaisala-specific SDI-12 Commands Supported by WS425 62
Measurement Unit Change (aXUx!)............................... 62
Heater Control Command (aXHx!)................................. 63
Check Current Submode (aX?!)..................................... 63
Place Sensor in Submode B (aXQx;c.c;n;yyyy!)............ 64
Reset the Sensor to Submode A Command (aXS!) ...... 65
Check Current Measurement Unit (aX*!) ....................... 65
SDI-12 TIMING ................................................................... 66
CHAPTER 5
Visual Inspection of WS425 Ultrasonic Wind Sensor......... 69
Periodic Testing ..................................................................... 71
CHAPTER 6
TROUBLESHOOTING ................................................................................. 73
Common Problems ................................................................ 73
Frequently Asked Questions (FAQ) .................................... 73
Instructions for Opening a Serial Terminal Connection to
WS425................................................................................. 75
Technical Support .................................................................. 76
Return Instructions ................................................................ 76
Vaisala Service Centers......................................................... 77
CHAPTER 7
Specifications ......................................................................... 79
APPENDIX A
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List of Figures
Figure 1
Different Wind Speed and Direction Presentations ..................18
Figure 2
Mounting the Sensor to Adapter...............................................24
Figure 3
WS425 Main Dimensions .........................................................25
Figure 4
Sketch of Magnetic Declination ................................................27
Figure 5
Suunto Compass MC-2 ............................................................28
Figure 6
Correctly Aligned WS425 Ultrasonic Wind Sensor...................29
Figure 7
Adjusting the N-S Heads ..........................................................30
Figure 8
Open-Lead Cables for WS425 Sensors ...................................32
Figure 9
Frequency Connection .............................................................36
Figure 10
Wind Speed ..............................................................................36
Figure 11
Analog Connection ...................................................................37
Figure 12
Timing Diagram ........................................................................67
Figure 13
Solder Spot and Sensor Handling ............................................70
Figure 14
Verifier ......................................................................................72
Figure 15
WS425FIX30 Adapter...............................................................81
Figure 16
WS425FIX60 Adapter...............................................................82
Figure 17
WS425FIX60 Adapter...............................................................83
List of Tables
Table 1
Manual Revisions .......................................................................8
Table 2
Sensor Ordering Options vs. Supported Data Outputs ..............9
Table 3
Ordering Codes ..........................................................................9
Table 4
Maximum Voltages ...................................................................11
Table 5
Sensor Features .......................................................................17
Table 6
Wind Direction Coasting ...........................................................20
Table 7
Gust Wind Speed and Direction Over Averaging Time ............20
Table 8
WS425 Sensor Pins .................................................................31
Table 9
The Handar RS-232 Polling Commands ..................................41
Table 10
The RS-232 19-character Fixed Length Output Message .......42
Table 11
Checksum Table.......................................................................45
Table 12
Consecutive Measurements of Wind Direction ........................49
Table 13
Logic and Voltage Level for Serial Data ...................................52
Table 14
Byte Frame Format for SDI-12 .................................................53
Table 15
SDI Timing Chart ......................................................................54
Table 16
Technical Specifications ...........................................................79
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Chapter 1 ________________________________________________________ General Information
CHAPTER 1
GENERAL INFORMATION
This chapter provides general notes for the product.
About This Manual
This manual provides information for installing, operating, and maintaining the WS425 Ultrasonic Wind Sensors.
Contents of This Manual
This manual consists of the following chapters:
- Chapter 1, General Information, provides general notes for the product.
- Chapter 2, Product Overview, describes the features of the WS425
- Chapter 4, Operation, explains the operation and programming of
- Chapter 5, Maintenance, provides you with general maintenance information.
- Chapter 6, Troubleshooting, provides you information on common problems.
- Chapter 7, Technical Data, gives the technical data on the product.
- Appendix A, Drawings, includes detailed pictures of the adapters.
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USER'S GUIDE____________________________________________________________________
Version Information
Table 1
Manual Code
U428en-1.1
M210361en-A
Manual Revisions
Description
Applicable to Models WAS425A and WAS425AH
Firmware versions 1.04.
Previous version of the manual. measurement range of the wind speed in the technical data.
M210361EN-D
M210361EN-E
Chapter 5, Maintenance, section Visual Inspection of
WS425 Ultrasonic Wind Sensor added.
Updated power requirements. New section on mounting the sensor upside down.
Correction to salt spray test: MIL-STD-810 Method
509.
Feedback
Vaisala 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]
8 ___________________________________________________________________ M210361EN-E
Chapter 1 ________________________________________________________ General Information
Table 2 Sensor Ordering Options vs. Supported Data Outputs
Sensor Ordering Options Sensor Cable Supported Operating
Modes
WS425 x 1 ... (Analog/
SDI-12/RS-232USA)
WS425 x 2 ... (RS-232/
RS-485/RS-422
SDI-12 cable
Analog cable
RS-232 cable
RS-232 cable
RS-422/
RS-485 cable
SDI-12 submode A
SDI-12 submode B
Analog mode
Serial mode with wind speed unit = miles per hour
Serial mode with wind speed unit = meters per second
Supported Data Outputs
SDI-12 standard commands
WS [Hz] 0 ... 65
WS [V] 0 ... 1
WD [V] 0 ... Vref
RS-232
NMEA message
Vaisala WATT 11 message
Vaisala Handar message
RS-232
NMEA message
Vaisala WATT 11 message
Vaisala Handar message
RS-422
NMEA message
Vaisala WATT 11 message
Vaisala Handar message
RS-485
NMEA message
Vaisala WATT 11 message
Vaisala Handar message
Table 3 Ordering Codes
425AH WS425 B
425SH WS425 B
WAS425A and WAS425A-C
WAS425AH and WAS425AH-C
WS425
WS425
A
B
2
2
A
A
2
2
B
B
WAS425S and WAS425S-C
WAS425SH and WAS425SH-C
WS425
WS425
A
B
2
2
A
A
2
2
B
B
425T-1 WS425 B
E A
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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.
Product Related Safety Precautions
Inverted Mounting
WARNING
Do not install the WS425 upside down in an airport application.
Absolute Maximum Voltages
The absolute maximum voltages that may be applied to WS425 sensor
are listed in Table 4 on page 11. The following limits do not damage the
sensor but they are not operational limits.
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Chapter 1 ________________________________________________________ General Information
Table 4 Maximum Voltages
Pin Min. volts Max. volts
1
2
3
4
5 -0.3
6 -0.3
7
8
9 -12.0
10 -12.0
11 -0.5
12 -0.5
13 -10.0
14 -10.0
15 -0.5
16 -5.0
5.3
5.3
20.0
20.0
18.0
5.3
12.0
12.0
5.3
42.0
Ordering Options
WS425 x 2 ...
Ground
Ground
Ground
N/C
Jumper
Jumper
Ground
Ground
Digital Output
Digital Input
+12 V Power
Digital Output
N/C
Digital Input
N/C
Heater Power
WS425 x 1 ...
Ground
Ground
Ground
N/C
Jumper
Jumper
Ground
Ground
Digital Output
Digital Input
+12 V Power
Analog Input
Analog Output
Heater Power
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.
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USER'S GUIDE____________________________________________________________________
Regulatory Compliances
The Vaisala WS425 Ultrasonic Wind Sensor has been tested to fulfill the following regulatory compliances. Also mentioned here are some thirdparty tests that involved field testing of the sensor.
EN55011 Class A Group 1 & EN50082-2
- Electrical task transient burst surge
- Voltage dips & interrupts
MIL-STD-426 Method RS03
MIL-STD 810 Method 509
- Salt spray test
MIL-STD 202 Method 213
MIL-STD-167-1 (SHIPS)
12 __________________________________________________________________ M210361EN-E
Chapter 1 ________________________________________________________ General Information
Third-Party Testing (Field Tests
Included)
NWS ASOS Mechanical Wind Sensor Replacement
Vaisala has participated in a three-year test program conducted by the
U.S. National Weather Service ASOS Program group. The NWS has conducted a variety of tests including wind tunnel tests from 0 to 120 knots and field tests in various locations.
Lawrence Livermore Labs
Lawrence Livermore Labs tested the sensor independently and Grank
Gouveia and Ron Baskett have published a paper titled Evaluation of a
New Sonic Anemometer for Routing Monitoring and Emergency
Response Applications. A second paper titled Comparison of In-Situ
Data from the Handar Sonic Anemometer and the Met One Cup and
Vane [AMS proceedings of the 10th symposium on Meteorological
Observations and Instrumentation] published by Frank Gouveia and
Thomas Lockhart.
Tennessee Valley Authority
The TVA conducted comparative field tests of mechanical cup and vane sensors versus the Vaisala WS425 Ultrasonic Wind Sensor. The results were published in the AMS conference in 2001 by authors Kenneth G.
Wastrack and Doyle E. Pittman et al.
CETIAT (Centre Technique des Industries Aéraulique et Thermiques)
CETIAT has evaluated the accuracy of the WS425 Ultrasonic Wind
Sensor in a wind tunnel against a laser Doppler anemometer (LDA) reference sensor.
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USER'S GUIDE____________________________________________________________________
Trademarks
Vaisala WINDCAP® is a registered trademark of Vaisala Oyj.
Windows® is a registered trademark 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.
14 __________________________________________________________________ M210361EN-E
Chapter 2 __________________________________________________________ Product Overview
CHAPTER 2
PRODUCT OVERVIEW
This chapter describes the features of the WS425 Ultrasonic Wind
Sensors.
Introduction to WS425
Measuring Principle
The WS425 Ultrasonic Wind Sensor has an on-board microcontroller that captures and processes data and performs serial communications.
The wind sensor has an array of three equally spaced ultrasonic transducers on a horizontal plane. The sensor measures transit time, the time that it takes the ultrasound to travel from one transducer to another.
The transit time is measured in both directions.
The transit time depends on the wind velocity along the ultrasonic path.
For zero wind velocity, both the forward and reverse transit times are the same. With wind along the sound path, the up-wind transit time increases and the down-wind transit time decreases.
The microprocessor of the microcontroller calculates the wind speed from the transit times using the following formula:
V
W
=
0 .
5
⋅
L
⋅
(1/t f
−
1 / t r
) where:
V w
L t f t r
= The distance between two transducers
= The transit time in the forward direction
= The transit time in the reverse direction.
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USER'S GUIDE____________________________________________________________________
Measuring the six transmit times allows wind velocity to be calculated for each of the three ultrasonic paths, which are offset to each other by
120°. The calculated wind speeds are independent of altitude, temperature, and humidity because they cancel out with the six measurements even though the velocity of sound affects individual transit times.
Incorrect readings may occur when a large raindrop or ice pellet hits a transducer. They are eliminated by a proprietary signal processing technique. The wind velocity that is most affected by turbulence error is eliminated so that wind speed and wind direction are calculated from the best two vectors.
Sensor Operating Modes
There are four modes of operation that give different information:
- Analog
- SDI-12 mode A
- SDI-12 mode B
Only one of these modes can be operated at a time. The sensor must be ordered according to the desired mode of operation.
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Chapter 2 __________________________________________________________ Product Overview
Sensor Features
Some of the sensor features depend on the WS425 operating mode. Table
5 below outlines where the features are available.
Sensor Feature
Table 5 Sensor Features
Operating Mode submode A submode B
Polar wind speed and direction
Wind speed x and y components
Scalar averaging of wind speed and direction
Yes Yes Yes Yes
No No Yes Yes
1 s ... 9 s No No 3 s ... 1 h
Vector averaging of wind speed and direction
Wind direction coasting
Wind direction reversible
1 s ... 9 s No No 3 s ... 1 h
Yes No No Yes
Yes No No No for upside down mounting
Enable/disable heater command
Gust wind speed and direction over averaging time
No No Yes Yes
Selectable wind speed unit Yes
Calculate from instant data
No
Calculate from instant data
Yes Yes
Yes Yes
Low-current standby
(sensor sleep)
Current with 1 Hz measurement
No No 0.2
18 mA@
12 VDC
12 mA@
12 VDC
Data acquisition by polling Yes
Continuous data transmission
No
1 ... 9 s interval Yes
12 VDC
7.7 mA@
12 VDC
Yes
No
7.7 mA@
12 VDC
12 mA@
12 VDC
Yes
No
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Polar Wind Speed and Direction
The wind speed (WS) is represented as a scalar speed in selected units
(m/s, kt, mph, km/h). The wind direction (WD) is expressed in degrees
(
°).
Figure 1
0212-044
Different Wind Speed and Direction Presentations
Wind Speed X and Y Components
The wind speed (x, y) is represented as two scalar speeds, one parallel to the N-S direction (x) and the other (y) parallel to the W-E direction The speed unit may be m/s, kt, mph, or km/h. x = WS
× cos (WD) y = WS
× sin (WD)
Scalar Averaging of Wind Speed and
Direction
The scalar average of wind speed and wind direction is available in both
SDI-12 submode B and serial modes. The time between each consecutive wind speed and wind direction measurement is one second. Each wind
18 __________________________________________________________________ M210361EN-E
Chapter 2 __________________________________________________________ Product Overview speed measurement taken over the preceding averaging interval is summed and the sum is then divided by the number of measurements.
The sensor computes the true running average. If the Data Acquisition
System requests data before the initial averaging interval completes, the sensor returns the best possible running average.
In SDI-12 submode B, the average is determined over the averaging interval specified, which ranges from three seconds to one hour.
In RS-232 mode, the average is determined over the averaging interval specified, which ranges from one to nine seconds.
Wind direction is a circular function with a discontinuity at north, where
360 degrees is equal to zero degrees. For example:
359
° + 5° = + 4°
0
° - 5° = 355°
The microprocessor translates the circular function to a linear function so that 359
° + 5° is translated to 364°. Also, 0° - 5° translated to 355°. This way the wind direction average stays representative of the true situation even if individual samples occur in both sides of the zero direction.
Vector Averaging of Wind Speed and
Direction
The vector average is available in SDI-12 submode B and serial mode.
Each x velocity and y velocity measurement over the averaging interval is added and then divided by the number of measurements. The resultant average x velocity and average y velocity are converted to polar direction and magnitude, returning as the average direction in degrees and speed in the chosen units. The average is determined over the specified averaging interval (0 ... 9 s for serial mode,
3 s ... 1 h for SDI-12 submode B). The sensor computes a true running average. If the DAS requests data before the initial averaging interval completes, the sensor returns the best possible running average. The averaging calculation uses the direction coast speed.
Wind Direction Coasting
At very low wind speeds, the measured wind direction is meaningless.
Therefore, you can specify a direction coast speed. When the measured wind speed drops below the direction coast speed, the calculations use the last wind direction that occurred while the wind speed was at or above the direction coast speed to the average wind direction. You can
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USER'S GUIDE____________________________________________________________________ specify a direction coast speed between 0.0 and 9.9 units of measurement. Use 0.0 if coasting is not required.
For example, making the direction coast speed = 2.0. The consecutive
measurements are presented in Table 6 below.
Table 6 Wind Direction Coasting
Measured Wind Speed Measured Wind
Direction
Wind Direction Used for Averaging
3.5 350 350
2.5 340 340
2.2 340 340
2.1 345 345
Gust Wind Speed and Direction Over
Time
The gust wind speed and direction are available in SDI-12 submode B. It is the highest wind speed and direction recorded during the averaging interval. The gust averaging count can be specified, which is the number of measurements (one measurement each second) average to produce the gust values for speed and direction. It has a range of one to nine counts.
As a gust averaging count is specified as one, the reported wind gust is the highest instantaneous reading. An example of a gust averaging count
Table 7 Gust Wind Speed and Direction Over Averaging Time
Wind 8 7 6 3 5 3 4 9 8 7 6 10 sum 5 - - - - 29 29 29 29 29 31 34 40 43 46
Gust averaging sum of last 5
[29] [24] [21] [24] [29] [31] [34] [40] [43] [46]
Gust wind speed
(sum of highest
5) divided by 5
Sum of all wind speed
Average wind speed
8 15 21 24 29 32 36 45 53 60 66 76 88 99
8 7.5 7.0 6.0 5.8 5.3 5.1 5.6 5.9 6.0 6.0 6.3 6.8 7.1
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Chapter 3 _______________________________________________________________ Installation
CHAPTER 3
INSTALLATION
This chapter provides you with information that is intended to help you install this product.
Selecting Location
WS425 Ultrasonic Wind Sensor should be installed in a location that is free from turbulence caused by nearby objects, such as trees or buildings.
Ideally, the sensor should be higher than any other object within the horizontal radius of 300 m.
WARNING
To protect personnel (and the wind sensor), a lightning rod must be installed with the tip at least one meter above the wind sensor. The rod must be properly grounded, compliant with all local applicable safety regulations.
Installation Procedure
Unpacking Instructions
The ultrasonic wind sensor comes in a custom shipping container. The sensor must be removed from the container carefully. It is important to save the container and all the foam packing for future transporting or shipping.
The sensor comes with a Hex-socket bolt and a grooved bolt to be used in mounting.
CAUTION
Never move the WS425 Ultrasonic Wind Sensor until it is in its custom shipping container. Otherwise, the warranty will become void.
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CAUTION
A transducer is located at the top of each of the three arms. Be careful not to damage any of the transducers. Dropping the sensor can break or damage the transducer or the arms will bend and they cannot be realigned. Damage can also be caused if the transducers are twisted (the transducers are not screwed into the arms).
NOTE
Factory Settings
There are two different factory settings available for WS425 if a serial
RS-232 protocol is used. For RS-485 and RS-422 protocols, only a single factory configuration is available.
The factory settings are for firmware version v6.12 unless indicated otherwise.
RS-232 Default Settings for USA
Operation Mode:
Wind Speed Units:
Handar RS-232
Miles/Hour
Average Interval (seconds):
Averaging Method:
Output Interval (seconds, 0 for polled):
Sensor ID Character:
1
Scalar
0
A
Wind Direction Coast Threshold (speed units): 0.0
Head Orientation:
Baud Rate:
Up
2400b
Parity: None
Data Bits:
Save Configuration
Do Zero Speed Calibration
Resume Operation
8
These default settings are delivered with product ordering options x1xxx
(for example, WS425 A1A2A, where the number 1 refers to the default settings).
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Chapter 3 _______________________________________________________________ Installation
Default Settings of RS-232, RS-422, and
RS-485 for Europe
Operation Mode:
Wind Speed Units:
Average Interval (seconds):
NMEA Extended
Meters/Second
3
Averaging Method:
Output Interval (seconds, 0 for polled):
Scalar
1
Sensor ID Character: A
Wind Direction Coast Threshold (speed units): 0.0*
Head Orientation:
Baud Rate:
Up
9600b
Parity: None
Data Bits: 8
* 0.2 in sensors that are delivered to airport applications
NOTE
These default settings are delivered with product ordering options x2xxx
(for example, WS425 A2A1A, where the number 2 refers to the default settings.)
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Figure 2 Mounting the Sensor to Adapter
The following numbers refer to Figure 2 above.
0311-011
1 = Sensor body
2 = Cable connector
3 = Spacer ring
4 = 3/16 inch Hex-socket bolt or standard screw
5 = Sensor adapter
6 = Fastening clamp
7 = Vertical tube
The dimensions of the adapter are illustrated in Figure 3 on page 25.
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Chapter 3 _______________________________________________________________ Installation
0212-045
Figure 3 WS425 Main Dimensions
The dimensions are in millimeters.
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USER'S GUIDE____________________________________________________________________
Mounting
Mounting Procedure on a 1-inch IPS Vertical Pipe
Use the following procedure to mount the sensor normally to a vertical 1inch International Pipe Standards (IPS) pipe. WS425FIX30 is suitable for the 1-inch IPS vertical pipe and WS425FIX60 is suitable for a 60-mm
vertical pipe (Europe). See Figure 2 on page 24 for details.
To mount the sensor, do the following:
1.
2. Connect the cable to the sensor, routing it through the adapter.
3. Attach the adapter to the sensor body and tighten the bolt.
4. Run the cable out of the adapter slot between the sensor and the clamp. Optionally, you can run the cable inside the vertical pipe.
5. Place the sensor on the pipe and slightly tighten the clamp’s bolt.
6.
Align wind direction as explained in section Alignment on page 27.
Inverted Mounting
To provide additional protection agains the accumulation of snow and interference from birds, the WS425 can be installed so that the transducer arms face down. Note the following:
- The WS425 must be in the serial operation mode. See section Serial
- Configure the Head Orientation parameter accordingly. See section
- Protect the connector from rain and snow.
WARNING
Do not install the WS425 upside down in an airport application.
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Alignment
NOTE
Magnetic Declination Correction
One transducer arm is permanently marked with an N for north and another with an S for south.
Aligning might be easier if you mark the sensor body, for example, with paint or colored tape, to indicate north and south so that it can be seen from the ground.
Wind direction can be referenced to 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. See Figure 4 below.
NOTE
0003-011
Sketch of Magnetic Declination Figure 4
The source for the magnetic declination must be current as the declination changes over time.
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Figure 5 Suunto Compass MC-2
0212-048
Compass Alignment with a Mast Adapter
The following steps aim the wind sensor when using the
1-inch adapter for mounting.
1. Use the compass to determine that the N-S transducer heads of the ultrasonic wind sensor are exactly in line with the compass. Adjust the heads by moving them to the left or right. For the correct
ground position of the installer, see Figure 7 on page 30.
2. If the alignment is not correct, lower the tower.
3. Loosen the clamp at the bottom of the sensor’s adapter and rotate the sensor so that the heads marked with the N and with the S are exactly aligned to north and south when the tower is set up. Tighten the clamp.
4.
Raise the tower to the vertical position. Figure 6 on page 29 shows
the correct alignment.
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Figure 6 Correctly Aligned WS425 Ultrasonic Wind Sensor
0208-025
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Figure 7 Adjusting the N-S Heads
The following letters refer to Figure 7 above.
0208-024
A = The installer is too far to the left.
B = The installer is in line with the sensor.
C = The sensor's appearance is shown when the installer is in the correct position. The sensor, however, is not correctly aligned.
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Connections
WS425 has a 16-pin circular plastic connector (male) at the bottom of the sensor. A cable connector of type AMP206037-1 can be used to attach wires to the sensor pins.
CAUTION
When WS425 is installed upside down, always make sure the connector is protected from rain and snow.
Table 8 below illustrates usage of the pins with different protocols.
Table 8 WS425 Sensor Pins
Protocol
13
14
15
16
9
10
11
12
7
8
5
6
3
4
1
2
Sensor
Pin No.
RS-232
GND
GND
GND
-
GND
Data out (TxD)
Data in (RxD)
+12 VDC
-
-
-
-
+36 VDC
RS-422
GND
GND
GND
-
GND
Data out (T-)
Data in (R-)
+12 VDC
Data out (T+)
-
Data in (R+)
-
+36 VDC
RS-485 Analog SDI-12
GND
GND
GND
-
GND
GND
GND
-
GND
GND
GND
-
-
-
GND
RT-
RT-
GND
-
-
GND
GND
-
SDI data
+12 VDC +12 VDC +12 VDC
RT+
-
RT+
-
WD Vref in
WD Vout
WS Fout
WS Vout
-
-
-
-
+36 VDC +36 VDC +36 VDC
NOTE
The short-circuits between pins 5, 6, and 7 are required for selecting the protocol.
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Figure 8 Open-Lead Cables for WS425 Sensors
0212-041
For 10-meter cables that are available from Vaisala, see section
Technical Data on page 79. Choose the cable according to the desired
communication protocol.
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Powering
NOTE
Power Supplies
You can use any 12 VDC power supply with the unheated Ultrasonic
Wind Sensor, as long as it meets all applicable safety regulations.
Typically, the power supply is a fused 12 V battery with either a solar panel charger or a trickle charger.
The power supply must be capable of delivering 155 mA current spikes.
The current draw of the Ultrasonic Wind Sensor alternates between
14 mA when idle, and short peaks of 155 mA during measurement
(typical). The average current consumption is 29 mA RMS.
Some DC power supplies are based on a chopper circuit that operates at a 100 kHz frequency. Avoid using such power supplies with WS425 since the measurement can be distorted by the ripple in the DC output.
The heated ultrasonic wind sensors require +12 VDC for the sensor and
+36 VDC for the heater. The heating current is up to 0.7 A.
CAUTION
The heated Ultrasonic Wind Sensor is intended for operation when pin
16 is connected to a +36 VDC source. If you are operating WS425 when pin 16 is not connected to +36 VDC, you must ground pin 16. Never float pin 16 on WS425 because the sensor will not report accurate readings.
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CHAPTER 4
OPERATION
This chapter explains the operation and programming of WS425.
Analog Mode
The WS425 Ultrasonic Wind Sensor can be used as a conventional wind set that gives instantaneous readings. The sensor is normally powered down. When power is first turned on, it takes about two seconds for the sensor to initialize and stabilize. Then the sensor takes a 0.35-second measurement and synthesizes the analog outputs of wind speed and wind direction. The cycle is repeated every second until power is turned off.
Wind Speed
The factory sets the wind speed unit of the analog mode to miles per hour. This is the only option available for the analog mode.
The wind speed output at pin 14 is 0 to 12 V pulsed output with a frequency proportional to wind speed. Every mile per hour adds 5 Hz to the frequency. In SI units, a change of 0.894 m/s adds 10 Hz to the frequency. A frequency counter is required to count the output in Hz and the calculation that scales the result to appropriate units.
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Figure 9 Frequency Connection
0212-039
The wind speed output at pin 15 is a voltage that varies linearly from 0
VDC at 0 mph to 1 VDC at 125 mph. In SI units, the voltage varies linearly from 0 VDC at 0 m/s to
1 VDC at 55.88 m/s.
Figure 10 Wind Speed
0212-038
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NOTE
The wind speed voltage output cannot be used simultaneously with the frequency output. If the voltage output pin 15 is used, the frequency
output pin 14 must be connected to ground, see Figure 10 on page 36.
Wind Direction
The DC reference voltage that inputs the sensor at pin 12, produces a voltage that represents the wind position. The reference voltage must be in the range of 1.0 to 4.0 VDC. The output at pin 13 is 0 VDC at zero degrees and increases to the maximum input voltage at 359 degrees.
Figure 11 Analog Connection
0212-040
Missing Readings
For analog outputs, the wind speed is set to 125 mph when a reading is missing.
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Serial Mode
NOTE
NOTE
Overview
You can use any computer or data logger that has a serial port to collect the sensor data by using the serial commands. The communication speed, parity, and number of data bits for the serial line can be selected by the user. The sensor can be set to transmit data messages at predefined intervals (autosending) or it responds to a polling string, which is specific to a selected output message format. Various operational parameters can be set through a terminal connection.
Since the serial line settings may not be known for a device, the settings are held as constant for the first five seconds after powering up the sensor. During this time, the sensor responds to commands issued with settings such as 9600 bit/s, 8 data bits, parity None, 1 stop bit.
Serial Mode Default Settings for the USA
Vaisala WS425 Ultrasonic Anemometer, Firmware Version v6.04.
Operation Mode:
Wind Speed Units:
Average Interval (seconds):
Handar RS-232
Miles/Hour
1
Averaging Method:
Output Interval (seconds, 0 for polled):
Scalar
0
Sensor ID Character: A
Wind Direction Coast Threshold (speed units): 0.0
Head Orientation:
Baud Rate:
Up
2400b
Parity: None
Data Bits: 8
Save Configuration
Do Zero Speed Calibration
Resume Operation
These default settings for the USA are used for product ordering options x1xxx (for example, WS425 A1A2A, where number 1 refers to the default settings.)
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Serial Mode Default Settings for Europe
Operation Mode:
Wind Speed Units:
Average Interval (seconds):
NMEA Extended
Meters/Second
3
Averaging Method:
Output Interval (seconds, 0 for polled):
Scalar
1
Sensor ID Character: A
Wind Direction Coast Threshold (speed units): 0.0
Head Orientation:
Baud Rate:
Up
9600b
Parity: None
Data Bits: 8
NOTE
These default settings for Europe are used for product ordering options x2xxx (for example, WS425 A2A1A, where the number 2 refers to the default settings).
Configuration Menu
The configuration menu can be opened by typing
Open
or
Open <id> where
<id>
is the identification character of the sensor.
If the sensor has been running for more than five seconds, use the currently active baud rate and other communication settings. There is a short timeout in typing in the characters. Therefore, type the OPEN command followed by ENTER relatively fast.
The OPEN command displays the following menu (on the next page):
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Vaisala WS425 Ultrasonic Anemometer
Firmware Version v6.00
1. Operation Mode: WAT11
2. Wind Speed Units: Meters/Second
3. Average Interval (seconds): 3
4. Averaging Method: Vector
5. Output Interval (seconds, 0 for polled): 0
6. Sensor ID Character: A
7. Wind Direction Coast Threshold (speed
units): 1.0
8. Head Orientation: Up
9. Baud Rate: 9600b
10. Parity: None
11. Data Bits: 8
12. Save Configuration
13. Do Zero Speed Calibration
14. Resume Operation
Enter Function Number:
Each configuration parameter is displayed together with the currently active setting. The configuration parameters can be changed by selecting the number of the parameter followed by ENTER.
NOTE
After modifying the parameters, type 12 for storing the new parameter values and 14 to exit the configuration menu and to return to the measurement mode.
Configuration Commands
The first parameter selects the message format and polling commands for the sensor. The available options are: d. WAT11
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Handar RS-232
When the sensor uses the Handar RS-232 message, it responds to polling
commands used for requesting data from the sensor. Table 9 below
summarizes these commands.
Table 9 The Handar RS-232 Polling Commands
Command Name
I Identify
Wx Measurement
Ux Measurement unit change
Page
Identify Command I
The identify command is I.
The following is an example of the command:
I
VAISALA WS425A/AH 600
Vaisala WS425A/AH is the vendor and model number, 600 is version
6.00 of models WS425A/AH.
Measurement Command Wx
The measurement command is Wx where x is the time for averaging wind speed and wind direction. x has a range of 1 to 9.
The following is an example of the command:
W5
☻W5P1200013.2TDE♥
The interpretation of the output message is described in Table 10 on page 42.
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Table 10 The RS-232 19-character Fixed Length Output
Message
5
6
7
8
Character position
Message
1 “ ☻” 02H (<STX>, start of transmission)
2 “W”
3
4
“5” for 5-second running average
“P” for “pass”
“F” for “fail”
Wind direction (most significant digit)
Wind direction (middle digit)
Wind direction (least significant digit)
9
10
11
12
Wind speed (most significant digit)
Wind speed (next digit)
Wind speed (next digit)
Wind speed (least significant digit)
13
14
“.” (dot character)
Wind speed (tenth digit)
“M” for miles per hour; “K” for knots
“L” for kilometers per hour; “T” for meters per second
15 Check sum (most significant digit) (See note)
16 Check sum (least significant digit)
17 “ ♥” 03H (<ETX>, end of transmission)
18
19
[CR] (carriage return)
[LF] (line feed)
NOTE
The checksum is calculated from 13 characters from position 2 through
14. The accumulator initializes at 0 with the addition of the byte value.
The checksum has a range of 0H … FFH.
Missing Readings
If data is missing due to a measurement problem, Handar RS-232 message reports 999.9 for wind speed.
NOTE
The sensor has a 20 ms timeout in receiving characters. Therefore, polling strings should be transmitted by a programmable device, not as a user command via terminal sessions.
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Measurement Unit Change Command Ux
The measurement unit change command is Ux. where x = 0, for miles per hour, [mph] x = 1, for knots (default), [knot] x = 2, for kilometers per hour, [km/h] x = 3, for meters per second, [m/s]
The following is an example:
U3
It sets meters per second for wind speed.
NMEA Standard
The standard variable length, comma-separated, MWV wind message is defined by NMEA 0183 V2.20 as follows:
$WIMWV,<dir>,<ref>,<spd>,<uni>,<sta>*<chk><cr><lf> where
<dir>
<ref>
=
=
Wind angle, 0 to 359 degrees
Reference; R=Relative, T=True
<spd> = speed
<uni>
<sta>
= Wind speed units; K = kmph [km/h],
M = mps [m/s], N = kt
= Status; A = Data Valid, V = Invalid Data
NOTE
<cr>
<lf>
=
=
(8-bit XOR, excluding $ and *)
Carriage return code, ASCII 0DH
Line feed code, ASCII 0AH
When the NMEA Standard message format is selected, the sensor must have a non-zero output interval setting (parameter 5 in the configuration menu) since no polling command is defined for this message type.
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Missing Readings
If data is missing due to a measurement problem, the NMEA messages will only show the commas (,) between the data fields. Thus, NMEA is a variable-length data message.
NMEA Extended Message
Vaisala extension to the standard MWV wind message is defined as follows:
$P<id>MWV,<dir>,<ref>,<spd>,<uni>,<sta>*<chk><cr><lf> where
NOTE
<id>
<dir>
<ref>
<uni>
<sta>
= Is the data ID; A … Z
= Wind angle, 0 to 359 degrees
= Reference; R = Relative, T = True
=
=
Wind speed units; K = kmph [km/h],
M = mps [m/s], N = kt
Status; A = Data Valid, V = Invalid Data
<chk>
<cr>
<lf>
= Checksum (8-bit XOR, excluding $ and *)
= Carriage return code, ASCII 0DH
= Line feed code, ASCII 0AH
The sensor has a 20 ms timeout in receiving characters. Thus, polling strings should be transmitted by a programmable device, not as a user command via terminal sessions.
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In NMEA Extended Message, the polling can be done using the following command:
$WIP<id>Q,*<chk><cr><lf> where
<id> = Is the data ID; A … Z
NOTE
<chk>
<cr>
<lf>
=
=
=
Checksum (8-bit XOR, excluding $ and *)
Carriage return code, ASCII 0DH
Line feed code, ASCII 0AH
Table 11 Checksum Table
ID Character
<id>
Checksum <chk> Polling String
A 72 $WIPAQ,*72<cr><lf>
B 71 $WIPBQ,*71<cr><lf>
C 70 $WIPCQ,*70<cr><lf>
D 77 $WIPDQ,*77<cr><lf>
E 76 $WIPEQ,*76<cr><lf>
G 74 $WIPGQ,*74<cr><lf>
K 78 $WIPKQ,*78<cr><lf>
M 7E $WIPMQ,*7E<cr><lf>
When using the sensor in the NMEA Extended mode, you can either set the output interval to zero (parameter 5 in the configuration menu) to enable polling or use some fixed output interval.
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NOTE
WAT11 Message
The fixed length format of the WAT11 message is defined as follows:
<stx><id><spd><dir> where
<stx> = Start of text character (1 digit)
<id> = Sensor identification character, for example, A
(one digit).
<spd> = Wind speed (in m/s) multiplied by 10, for example,
045 is 4.5 m/s (three digits).
<dir> = Wind direction with two octal numbers for 6-bit binary data, for example, 45
8
= 37
10
corresponds to
37/64*360 = 208 degrees
The WAT11 polling command is defined as follows:
<esc><id> where
<esc> = Escape character ASCII 27H
<id> = Sensor ID, for example, A.
Missing Readings
The WAT11 message reports missing data as slashes (/////).
The sensor has a 20 ms timeout in receiving characters. Therefore, polling strings should be transmitted by a programmable device, not as a user command via terminal sessions.
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Wind Speed Units
There are four wind speed units available: a. Miles/hours b. Knots c. Kilometers/hours d. Meters/seconds
NOTE
When the operation mode is WAT11 (selected from the configuration parameter 1), the only option for the wind speed unit is meters/second as the WAT11 message does not contain wind speed unit information.
Average Interval
The averaging interval can be selected as full seconds between 1 and 9 seconds. For the WS425 sensor, the time between each consecutive wind direction measurement is one second. Each wind direction measurement taken over the preceding averaging interval is summed and the sum is divided by the number of measurements.
The same averaging interval is used for both the average wind speed and average wind direction.
The sensor computes a true running average. If the data acquisition system requests data before the initial averaging interval completes, the sensor returns the best possible running average.
Averaging Method
These settings affect the calculation of wind speed and direction. The available options are as follows:
Scalar Averaging
When the scalar averaging is selected, the wind direction is a circular function with a discontinuity at due north, where 360° is equal to 0°. For example, 359° + 5° = + 4° and
0° - 5° = 355°.
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The microprocessor translates this circular function to a linear function, that is, 359° + 5° is translated to 364° and
0° - 5° translates to - 5°.
To calculate the scalar average wind direction, each translated wind direction measurement taken over the preceding averaging interval is summed and the sum is divided by the number of measurements.
Vector Averaging
Each x velocity and y velocity measurement over the averaging interval is added and then divided by the number of measurements. The resulting average x velocity and average y velocity are converted to polar direction and magnitude, returning as average direction in degrees and speed in the chosen units.
NOTE
Output Interval
The output interval can be selected in full seconds between 1 and 9 seconds. These settings are independent of the averaging interval
(configuration parameter 3, see section Average Interval on page 47).
Regardless of the length of the output interval, the last measurement sample before transmission is always the last sample of the averaging window. Therefore, the transmitted data is always based on the latest measurements.
If the output interval is set to zero (0), polling is used in data acquisition.
When using the NMEA Standard as the operating mode (configuration parameter 1), there must be a non-zero setting for output interval since polling is not supported in the NMEA Standard mode.
Sensor ID Character
The sensor ID character must be a single capital letter from A to Z.
Numbers or small letters are not accepted. After an ID is defined for a sensor, the configuration menu can be opened by typing open <id>.
This is useful if several sensors are sharing the same communication line.
When running the NMEA Extended or WAT11 mode, the sensor ID is part of the polling string.
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Wind Direction Coast Threshold
At very low wind speeds, the measured wind direction is meaningless.
Therefore, you can specify a direction coast speed. When the measured wind speed drops below the direction coast speed, the calculations use the last wind direction that occurred while the wind speed WS at or above the direction coast speed to average wind direction. You can specify a direction coast speed between 0.0 and 9.9 units of measurement. Use 0.0 if coasting is not required.
For example, the direction coast speed = 2.0. Consecutive measurements
are as presented in Table 12 below.
Table 12 Consecutive Measurements of Wind Direction
Measured Wind
Speed
Measured Wind
Direction
Wind Direction Used for
Averaging
3.5 350 350
2.5 340 340
2.2 340 340
NOTE
2.1 345 345
The wind direction coast threshold can be set to a non-zero value only when the averaging method (configuration parameter 4) is set to scalar.
Head Orientation
The sensor can be installed either transducers up or transducers down.
The wind direction calculation requires that the installation position is configured correctly to the sensor. The installation of the sensor upside down should be constructed in a way that prevents water from entering the sensor connector.
Bit Rate
The following options are available:
- 1200b
- 2400b
- 4800b
- 9600b
- 19200b
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The new bit rate setting is activated as soon as the configuration changes are saved (selection 12) and operation is resumed (selection 14).
NOTE
For the first 5 seconds after powering up the sensor, the serial line parameters are 9600b, 8, N, 1.
Parity
The following options are available:
- None
- Odd
- Even
Data Bits
The available options are 7 or 8 data bits.
Save Configuration
After adjusting one of the configuration parameters, apply this function to save the new settings.
Zero Speed Calibration
The zero speed calibration is done to all sensors in the factory before delivery. There is no reason to perform this tuning periodically. Instead, use the margin verifier for periodic testing as described in section
Periodic Testing on page 71. Do the zero speed calibration only after
possible firmware update or if the periodic test indicates too high wind speeds.
To perform the zero speed calibration, do the following:
1. Remove the bird spikes and install the verifier as described in
2. Select zero speed calibration from the configuration menu and wait until the sensor resumes to normal operation.
3. Check that the sensor passes the periodic test.
CAUTION
Do not perform the zero speed calibration unless the margin verifier is mounted on the sensor. Use this function only if you suspect that the sensor characteristics have changed.
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Resume Operation
After opening the configuration menu, return to the current mode of operation by selecting "Resume Operation". This selection terminates the configuration dialog.
NOTE
Changes to the configuration will not be saved automatically. Use the
SAVE CONFIGURATION command to save the changes.
SDI-12 Protocol
SDI-12 is a standard for interfacing data recorders with microprocessorbased sensors. The name stands for serial/digital interface at 1200 baud.
SDI-12 is intended for applications with the following requirements:
- Battery-powered operation with minimal current drain.
- Use of a single data recorder with multiple sensors on one cable.
- Up to 200 feet (60 meters) of cable between a sensor and a data recorder.
SDI-12 Support Group
The SDI-12 Support Group is an association of companies that produce and use SDI-12 products with the purpose of reviewing requests to enhance, clarify, or modify the
SDI-12 architecture and that votes on proposed changes to SDI-12. More information of the group, as well as the complete SDI-12 standard text is available from the SDI-12 web-site in the following address: www.sdi-
12.org/.
SDI-12 Electrical Interface
The SDI-12 electrical interface uses the SDI-12 bus to transmit serial data between SDI-12 data recorders and sensors. The SDI-12 bus is the cable that connects multiple SDI-12 devices. This is a cable with three conductors:
- A serial data line
- A ground line
- A 12-volt line
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NOTE
With Vaisala SDI-12 cable, code WS425CAB SDI the lead colors are as follows: data - whi/yel; ground - Blk; and 12-volts - Brn.
The SDI-12 bus is can have at least 10 sensors connected to it. The bus topology is a parallel connection, where each of the 3 wires of different sensors are connected in parallel.
Serial Data Line
data for the SDI-12 standard. The data line uses negative logic.
Table 13 Logic and Voltage Level for Serial Data
Condition
Marking
Spacing
Transition
Binary State
1
0
Undefined
Voltage Range
-0.5 to 1.0 volts
3.5 to 5.5 volts
1.0 to 3.5 volts
Voltage Transitions
During normal operation, the data line voltage slew rate must not be greater than 1.5 volts per microsecond.
Impedance
When an SDI-12 device has its transmitter on, its direct current (DC) source resistance must be greater than 1000 ohms and less than 2000 ohms. When the transmitter of any SDI-12 device is off, or in a lowpower standby mode, the DC resistance to ground must be within 160 K to 360 K ohms. If an SDI-12 sensor does not use the 12-volt line for power, its data line resistance to ground while powered down must be within 160 K to 360 K ohms.
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SDI-12 Communications Protocol
SDI-12 data recorders and sensors communicate by an exchange of
ASCII characters on the data line. The data recorder sends a break to wake up the sensors on the data line. A break is continuous spacing on the data line for at least 12 milliseconds. The data recorder then sends a command. The sensor, in turn, returns the appropriate response. Each command is for a specific sensor. The first character of each command is a unique sensor address that specifies with which sensor the recorder wants to communicate. Other sensors on the SDI-12 bus ignore the command and return to low-power standby mode. When a data recorder tells a sensor to start its measurement procedure, the recorder does not communicate with any other sensor until the data collection from the first sensor is complete.
A typical recorder/sensor measurement sequence proceeds in the following order:
1. The data recorder wakes all sensors on the SDI-12 bus with a break.
2. The recorder transmits a command to a specific, addressed sensor, instructing it to make a measurement.
3. The addressed sensor responds within 15.0 milliseconds returning the maximum time until the measurement data will be ready and the number of data values it will return.
4. If the measurement is immediately available, the recorder transmits a command to the sensor instructing it to return the measurement(s). If the measurement is not ready, the data recorder waits for the sensor to send a request to the recorder, which indicates that the data is ready. The recorder then transmits a command to get the data.
5. The sensor responds, returning one or more measurements.
Baud Rate and Byte Frame Format
The baud rate for SDI-12 is 1200 b. Table 14 below shows the byte frame
format for SDI-12.
Table 14 Byte Frame Format for SDI-12
1 start bit
7 data bits, least significant bit transmitted first
1 parity bit, even parity
1 stop bit
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Two Different Submodes
Vaisala WS425 is designed to work in two different operational modes when running the SDI-12 protocol. These modes will be called "submode
A" and "submode B". This arrangement makes it possible to do the following:
- Keep the sensor in a sleep mode when measurement is not active, thus enabling a very low-power operation of the sensor (submode A).
- Initiate periods where continuous measurement is made. Long averages (up to 1 hour) of wind speed and direction, as well as gust data is available during this period (submode B).
As a default, the sensor runs in submode A. Specific commands can be issued in order to:
- Set the sensor into submode B and initiate continuous measurement.
- Collect averaged data in submode B.
- Force the sensor back to submode A.
If a sensor is not forced back to the low-power submode A by the data logger, the sensor will eventually do this independently after two hours
have elapsed. The timing diagram is illustrated in Table 15 below.
Table 15 SDI Timing Chart
Data Logger
Command aXQx;c.c;yyyy! aR0! aXS!
Time [s] Sensor Response
0 h
3600
(Sensor in submode A.) a<cr><lf>
(Sensor in submode B.) a<WS><WD><GS><GD><c r><lf>
(Sensor in submode B.) a<cr><lf>
(Sensor in submode A.)
Comment
Place sensor into submode B. yyyy is the averaging time.
Continuous measurements (if time is shorter than yyyy, only partial data is available).
Force the sensor back to submode A.
If aXS! was not given, the timer resets the sensor to submode
A.
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Chapter 4 ________________________________________________________________ Operation
Standard SDI-12 Commands Supported by WS425
Acknowledge Active Command (a!)
This command is used to ensure that a sensor is responding to a data recorder or another SDI-12 device. It asks a sensor to acknowledge its presence on the SDI-12 bus.
The command is the following: a! where a
!
=
=
The sensor address.
Terminates the command.
The response is the following: a<CR><LF> where a = The sensor address. The default values is zero
(0).
<CR><LF> = Terminates the response.
The following is an example of the command:
0!
The following is an example of the response:
0<CR><LF>
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Send Identification Command (aI!)
This command is used to query sensors for their SDI-12 compatibility level, model number, and firmware version number.
The following is an example of the command: aI! where
! a
I
=
=
=
The sensor address.
The send identification command
Terminates the command.
The following is an example of the response: allccccccccmmmmmmvvvxxx . . . xxx<CR><LF> where a ll cccccccc
= The sensor address.
= The SDI-12 version number, indicating
SDI-12 version compatibility; for example, version 1.1 is encoded as 11.
= An 8-character vendor identification Vaisala_ vvv
For example, xxx ... xx
WS425.
= 3 characters specifying the firmware version
=
604.
An optional field, up to 13 characters, used for a serial number or other specific sensor information that is not relevant for operation of the data recorder (not used).
<CR><LF> = Terminates the response.
Address Query Command (?!)
When a question mark (?) is used as the address character with the acknowledge active command (a!), the sensor will respond as if it is being addressed on the SDI-12 bus. For example, if a sensor detects ?!, it will respond with a<CR><LF>
,
no matter what its address may be. This will allow a user to determine the address of a sensor. The user should understand that if more than one sensor is connected to the bus, they will all respond, causing a bus contention.
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Chapter 4 ________________________________________________________________ Operation
The command is the following:
?! where
! = Terminates the command.
The response is the following: a<CR><LF> where a = The sensor address.
<CR><LF> = Terminates the response.
Change Address Command (aAb!)
This command changes the address of a sensor. After this command has been issued and responded to, the sensor is not required to respond to another command for one second. This gives the sensor time to write the new address to non-volatile memory.
The command is the following: aAb! where a
A b
!
=
=
=
=
The sensor address.
The change address command.
The address to change to.
Terminates the command.
The response is the following: b<CR><LF> where b = The address of the sensor (will equal the new address or the original address if the sensor is unable to change the address).
<CR><LF> = Terminates the response.
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Start Measurement Command (aM!)
With this command, the sensor will make a measurement. The sensor will not return the measurement to the data recorder after this command.
It shows the time after which the measurement result can be retrieved using the D0! command and it also shows the number of parameters. The following is an example:
>0M!
00015
The SEND DATA (D0!) command must be issued to get the measurements.
The command is the following: aM! where a
M
!
= The sensor address.
= The start measurement.
= Terminates the command.
The response is the following: atttn<CR><LF> where a ttt n
= The sensor address.
= The specified time, in seconds, until the sensor will have the measurement ready (001).
= The number of measurement values the sensor will make and return in one or more subsequent D commands (5).
<CR><LF> = Terminates the response.
Send Data Command (aD0!)
This command is used to get instant data from the sensor. D0! must be preceded with an M! command or an V! command. The sensor responds by sending measurement data (after M!) or verification data (after V!).
In a SDI-12 system compliant with the standard, if the expected number of measurements is not returned in response to a D0! command, a data recorder issues D1!, D2!, and so on until all measurement values are
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Chapter 4 ________________________________________________________________ Operation received. The expected number of measurements is the one that WS received by the data recorder in response to an M! or V! command.
Multiple data requests are not needed with WS425, since all return values fit easily into one response string.
The command is the following: aD0! where a
D0
!
= The sensor address.
= The send data command.
= Terminates the command.
When the previous command WS aM! is given, the response is the following: a<WS><WD><x><y><s><CR><LF> where a
<WS>
= The sensor address.
= Polar wind speed in selected units, format:
+(ss)s.s
= Polar wind direction in degrees, format +(dd)d <WD>
<x> = x component of wind speed in selected units, format:
±(ss)s.s
<y> = y component of wind speed in selected units, format:
±(ss)s.s
<s> =
±(ss)s.s
<CR><LF> = Terminates the response.
The above are measurement data fields.
If data is missing due to a measurement problem (for example, blocked paths between transducers), the measurement data is replaced with 999 as follows:
>7D0!
7+999.9+9999+999.9+999.9+999.9
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When the previous command WS aV! is given, the response is the following: a<watchdog><WS_unit><SDI-mode><spare><CR><LF> where a = The sensor address.
<watchdog> = The number of times the watchdog has triggered. Ideally should be zero. Format: +(c)c
<WS_unit> = Wind speed unit. The options are:
+0 = mph
+1 = kt
+2 = km/h
+3 = m/s
<SDI-mode> = Current submode setting. The options are:
+0 = SDI-12 submode A
+1 = SDI-12 submode B
<spare> = 1 digit for factory use, format: +c
<CR><LF> = Terminates the response.
The above are verification data fields.
Continuous Measurements (aR0!)
A sensor that is able to continuously monitor the phenomena to be measured, does not require a start measurement command (M!). The data can be read directly with the R0! command.
WS425 uses this command when the sensor is set to work in SDI-12 submode B. The command retrieves averaged wind data and gust wind data. The averaging time window is selectable between 3 and 3600 seconds.
The command is the following: aR0! where
! a
R0
= The sensor address.
= The send continuous measurements command.
= Terminates the command.
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The response is the following: a<WS_ave><WD_ave><GS><GD><CR><LF> where a = The sensor address.
<WS_ave> = Average wind speed over the past yyyy
1
seconds in currently active units. Format: +(ss)s.s
<WD_ave> = Average wind direction over the past yyy
1
<GS> seconds in degrees. Format +(dd)d
= Gust wind speed; the highest n
1
measurement running average during the past yyyy
1
seconds, in currently active units. Format: +(ss)s.s
= Gust direction; n
1
second average over the same <GD> time period as the gust speed. Format: +(dd)d.
<CR><LF> = Terminates the response.
1) The parameters yyyy and n are issued to the sensor as a part of the
"Place sensor in submode B (aXQx;c.c;n;yyyy!)" command. This command must be given to the sensor before aR0!. See the command description for aXQ...! for full description of the parameters.
Start Verification (aV!)
a
V
!
This command tells the sensor to return a verification in response to a following D0! command. The WS425 verification data includes a watchdog count, sensor measurement unit settings and the current SDI mode setting.
The command is the following: aV! where
= The sensor address.
= The start verification command.
= Terminates the command.
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The response is the following: attn<CR><LF> where a tt n
= The sensor address.
= The time in seconds the sensor needs until it has the verification data ready (01)
= The number of verification data fields that will be returned (4).
<CR><LF> = Terminates the response.
Vaisala-specific SDI-12 Commands
Supported by WS425
Measurement Unit Change (aXUx!)
This command sets the desired measurement unit for wind speed. The command is available in submode A only.
The command is the following: aXUx! where a
XU x
= The sensor address.
= The change measurement unit command.
= Desired wind speed unit. The options are:
0 = mph (default value)
1 = kt
2 = km/h
3 = m/s
= Terminates the command. !
The response is the following: a+x<CR><LF> where a x
=
=
The sensor address.
The new wind speed setting.
<CR><LF> = Terminates the response.
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Chapter 4 ________________________________________________________________ Operation
Heater Control Command (aXHx!)
This command switches the sensor heating into active or disabled state.
In the active state, heating is still thermostatically controlled. The command works only for heated sensor models.
The command is the following: aXHx! where a
XH x
= The sensor address.
= The heater control command.
= The options are:
0 = disable the heater
1 = enable the heater
= Terminates the command. !
The response is the following: a<CR><LF> where a x
= The sensor address.
= The new wind speed setting.
<CR><LF> = Terminates the response.
Check Current Submode (aX?!)
The command is the following: aX?! where a
X?
!
= The sensor address.
= The check current submode command.
= Terminates the command.
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The response is the following: a+x<CR><LF> where a x
= The sensor address.
= The currently active submode. The options are:
0 = submode A
1 = submode B
<CR><LF> = Terminates the response.
Place Sensor in Submode B (aXQx;c.c;n;yyyy!)
This command sets the sensor into submode B which enables calculation of averaged wind data and gust wind speed and direction.
The command is the following: aXQx;c.c;n;yyyy! where a
XQ x c.c n
= The sensor address.
= The place sensor in submode B command.
= The desired wind averaging method. The
options are:
0 = use scalar averaging
1 = use vector averaging
= The wind direction coasting threshold in
the current wind speed units. The coasting
can only be used with scalar averaging.
= The number of samples that form the gust
wind speed and direction value (1 Hz
!
sampling). The valid range is 1 to 9. yyyy = The length of averaging window [s]
= Terminates the command.
The response is the following: a<CR><LF> where a = The sensor address.
<CR><LF> = Terminates the response.
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Chapter 4 ________________________________________________________________ Operation
Reset the Sensor to Submode A Command (aXS!)
When the sensor is set to submode B in order to compute averaged wind data, the sensor will stay in mode B until a
2-hour time period has elapsed. This computation period can be aborted earlier by issuing the command (XS!).
The command is the following: aXS! where
! a
XS
= The sensor address.
= The reset sensor to submode A command.
= Terminates the command.
The response is the following: a<CR><LF> where a = The sensor address.
<CR><LF> = Terminates the response.
Check Current Measurement Unit (aX*!)
The command is the following: aX*! where a
X*
!
= The sensor address.
= The check current measurement unit command.
= Terminates the command.
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The response is the following: a+x<CR><LF> where a x
= The sensor address.
= Currently active wind speed unit. The options are:
0 = mph
1 = kt
2 = km/h
3 = m/s
<CR><LF> = Terminates the response.
SDI-12 TIMING
The Figure 12 on page 67 shows a timing diagram for an SDI-12
command and its response. The tolerance for all SDI-12 timing is ±0.40 milliseconds. The only exception to this is the time between the stop bit of one character and the start bit of the next character. The maximum time for this is 1.66 milliseconds, with no tolerance.
- A data recorder transmits a break by setting the data line to spacing for at least 12 milliseconds.
- The sensor will not recognize a break condition for a continuous spacing time of less than 6.5 milliseconds. The sensor will always recognize a break when the line is continuously spacing for more than
12 milliseconds.
- When receiving a break, a sensor must detect 8.33 milliseconds of marking on the data line before it looks for an address.
- A sensor must wake up from a low-power standby mode and be capable of detecting a start bit from a valid command within 100 milliseconds after detecting a break.
- After a data recorder transmits the last character of a command, it must relinquish control of the data line within 7.5 milliseconds following the end of the stop bit. (Tolerance: +0.40 milliseconds.)
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Chapter 4 ________________________________________________________________ Operation
SENSOR DATA break
(at least 12 milliseconds) command response
SDI-12
Data Line
NOTE
marking
(at least 8.33 milliseconds) marking
(at least 8.33 milliseconds) sensor must respond within 15 maximum time
380 ms most commands
780ms D0,R0 commands
Figure 12 Timing Diagram
- After receiving the break and the command, the addressed sensor sets the data line to marking at 8.33 milliseconds and then send the response. (Tolerance: -0.40 milliseconds.) The start bit of the first response byte must start within 15 milliseconds after the stop bit of the last byte of the command. (Tolerance: +0.40 milliseconds.)
- After a sensor transmits the last character of a response, it must relinquish control of the data line within 7.5 milliseconds. (Tolerance:
+0.40 milliseconds.)
- No more than 1.66 milliseconds of marking are allowed between the end of the stop bit and the start bit (e.g., between characters) on any characters in the command or the response. (No tolerance.) This permits a response to an M command to be sent within a
380-millisecond window.
- Sensors must return to a low-power standby mode after receiving an invalid address or after detecting a marking state on the data line for
100 milliseconds. (Tolerance: +0.40 milliseconds.)
- When a recorder addresses a different sensor, or if the data line has been in the marking state for more than 87 milliseconds, the next command must be preceded by a break.
In addition to being a power consumption state, the low power standby mode is a protocol state and a break is required to leave that state.
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Chapter 5 ______________________________________________________________ Maintenance
CHAPTER 5
MAINTENANCE
This chapter provides you with general maintenance information.
Visual Inspection of WS425 Ultrasonic Wind
Sensor
WS425 Ultrasonic Wind Sensor is a very reliable and rugged sensor. It has been wind tunnel tested to over 175 knots for mechanical integrity.
However, the transducers are constructed of ceramic material and can be damaged by dropping or hitting the transducers. Likewise, applying enough force to bend the transducer arms will render the anemometer inoperative.
The wind sensor should be kept in its protective foam shipping container until the time for the installation on the wind mast or tower. The verifier should be placed over the sensor when the sensor is installed on the tower. This provides protection to the transducers and validates that the mechanical spacing of the transducers is within specifications.
Some cautions and inspection criteria are listed below:
1. Do not rotate the transducers. Rotating the transducers will destroy the array of the ultrasonic wind sensor. A soldering spot can be seen on each ceramic transducer. The soldering spots on the ceramic transducer must be oriented outside the array. For the
correct alignment, see Figure 13 on page 70. Do not rotate the
transducer if the soldering spot is not in the correct location.
Replace the wind sensor.
2. Do not pull the transducers. Pulling the transducers will destroy the array of the ultrasonic wind sensor. The black RTV sealant can be seen between the bottom of each transducer and the transducer mounting arm. The RTV sealant must be free of damage and it must provide a good seal between the transducer and the transducer mounting arm. If this seal is damaged, water may enter the wind sensor.
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3. Do not strike or bend the transducers. Striking or bending the transducers will destroy the array of the ultrasonic wind sensor. All the transducers should be parallel to each other. For the correct
alignment, see Figure 13 below.
4. The verifier should slide over the transducers without excessive force. This validates that the mechanical spacing of the transducers is within specifications.
5. Do not scrape or touch the transducers with sharp objects. Cutting the silicon rubber sleeve on the transducer affects the acoustical matching layer of the transducer and destroys the array of the ultrasonic wind sensor. The silicon rubber transducer sleeve must not be damaged.
0506-020
Figure 13 Solder Spot and Sensor Handling
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Chapter 5 ______________________________________________________________ Maintenance
Periodic Testing
Section Measuring Principle on page 15 explains that the sensor
measures how long it takes for an ultrasonic signal to travel from transmitter to receiver. Therefore, the accuracy of the sensor depends on the accuracy of two factors:
NOTE
NOTE
- The distance between the ultrasonic transmitter and receiver. This requires a measurement of the transducer arm trueness.
- The time-of-flight measurement circuit, which uses a crystal oscillator for its time reference.
The crystal oscillator is used by the communications circuit for the bit rate generator. If you use the serial communication modes and the oscillator loses accuracy, the sensor stops communicating. Thus, the sensor cannot send erroneous values produced by faulty timing.
Perform periodic testing to detect slow deterioration of the sensor before it significantly affects accuracy. Perform the test either in the field or in a laboratory. The periodic test uses the verifier, which is a small echo-free
chamber . The verifier is shown in Figure 14 on page 72.
The test consists of the following steps:
1.
Slip the verifier over the three transducers (see Figure 14 on page
72).
2. In outdoor conditions, secure the zero wind flow by covering the sensor and verifier.
3. The sensor must read less than 0.5 miles per hour
(0.22 m/s) with the verifier in place.
Some random data samples may be lost during the zero verifier test.
This, however, does not indicate that the sensor is faulty.
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Figure 14 Verifier
0003-016
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Chapter 6 ___________________________________________________________ Troubleshooting
CHAPTER 6
TROUBLESHOOTING
This chapter provides you information on common problems.
Common Problems
Frequently Asked Questions (FAQ)
Q = Question
A= Answer
Q:
I am looking for mounting options/products for the WS425 Ultrasonic
Wind Sensor. Preferably, a tripod mount. If none is available, are there
CAD files so we can design a tripod to fit this sensor?
A:
A drawing of an optional sensor adapter is included in Chapter 3 section
Installation Procedure on page 21. This adapter fits onto an 1" IPS
standard pipe. Following the dimensions of the adapter, you may prefer to design your own sensor mounting. See also a dimensional drawing of
the sensor in Appendix A on page 81. Please make sure that no obstacles
are near the sensor, especially at the level of the ultrasonic transducers.
Q:
We intend to install a WS425 to a radio link tower. Is the sensor sensitive to RF frequencies generated by GSM link antennas ?
A:
A radio link tower is an extremely demanding RF environment for any measurement device. The WS425 sensor has undergone electromagnetic compatibility tests in two different laboratories and is compliant with requirements of MIL-STD-461B and EN 61000-4-3. The tested
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USER'S GUIDE____________________________________________________________________ frequency range spanned from 10 kHz to 10 GHz. The tested sensors were only disturbed by frequencies occurring at the band from 95kHz to
107kHz, which is the range that the sensor uses for the ultrasonic measurement. Radio communication devices do not operate at this band.
Despite the heavy testing, the GSM link equipment may cause interference to an ultrasonic sensor due to extremely high electromagnetic field levels around the transmission antenna. In this type of installation, a small displacement of the sensor may completely remove an interference problem that occurs at a certain point of the mast.
Trial and error is really the only way of finding out whether RF disturbance will be an issue.
Q:
I have tried out my WS425. When I turn the power on the sensor is not sending any data. I used an RS-232 checker but the Tx line is not active
(no data is coming to my PC).
A:
By default, the sensor is set to a command-response mode (polling mode). This means that the sensor is waiting for a data request command from the data logger. If you want the sensor to automatically send data through the serial line, you need to open a maintenance connection to your WS425 sensor and configure parameter number 5, Output Interval, to have a non-zero value. In order to open a maintenance connection, see the attached procedure on the next page.
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Chapter 6 ___________________________________________________________ Troubleshooting
Instructions for Opening a Serial
Terminal Connection to WS425
1. Connect an RS-232 cable between your terminal computer, power supply and your sensor. If you are using a Vaisala
RS-232 cable with code ZZ45203, the cable colors are the following:
Connections to power supply:
Ground
+12 VDC
Black (WS425 pin 1) -
Brown (WS425 pin 11) -
Connections to terminal PC:
Red (WS425 pin 9)
Blu (WS425 pin 10)
Yellow (WS425 pin 8) -
-
-
RxD (PC 9-pin serial port, pin n:o 2)
TxD (PC 9-pin serial port, pin n:o 3)
GND (PC 9-pin serial port, pin n:o 5)
2. Open the Windows HyperTerminal program. From HyperTerminal, select File - Properties and click Configure. Set communication parameters 9600,8,N,1 and Flow Control as None.
5. Switch the sensor power supply on and off. Make sure that the sensor is completely powered down before reconnecting the power supply (Many power supplies store energy and need time to be discharged completely). During the first 5 seconds after the sensor starts up, the serial line settings will remain as 9600, 8, N, 1. After this, the programmed communication parameters will become effective.
You have 5 seconds time to type: open<Enter>
Make sure that the sensor is already on when you type the first letter. If you do not succeed, try several times and check your connections.
6. After a successful OPEN command, the sensor should display a configuration menu. You can now adjust the settings.
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Technical Support
For technical questions, contact the Vaisala technical support:
E-mail [email protected]
Phone (int.)
Fax
+358 9 8949 2789
+358 9 8949 2790
Return Instructions
If the product needs repair, please follow the instructions below to speed up the process and avoid extra costs.
1. Read the warranty information.
2. Write a Problem Report with the name and contact information of a technically competent person who can provide further information on the problem.
3. On the Problem Report, please explain:
- What failed (what worked / did not work)?
- Where did it fail (location and environment)?
- When did it fail (date, immediately / after a while / periodically / randomly)?
- How many failed (only one defect / other same or similar defects / several failures in one unit)?
- What was connected to the product and to which connectors?
- Input power source type, voltage and list of other items
(lighting, heaters, motors etc.) that were connected to the same power output.
- What was done when the failure was noticed?
4. Include a detailed return address with your preferred shipping method on the Problem Report.
5. Pack the sensor into the original shipping container. The sensor warranty will be void if another packing method is used.
6.
Send the box to the nearest Vaisala Service depot, see Vaisala
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Chapter 6 ___________________________________________________________ Troubleshooting
Vaisala Service Centers
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Chapter 7 ____________________________________________________________ Technical Data
CHAPTER 7
TECHNICAL DATA
This chapter gives the technical data on the product.
Specifications
Table 16 Technical Specifications
Wind Speed
Measurement range
Starting threshold
Delay distance
Resolution
Accuracy (range 0 ... 65 m/s)
Outputs
Digital outputs type bit rate available averages
SDI12- Standard Data Interface type bit rate available averages
Analog outputs
0 ... 65 m/s (0 ... 144 mph, 0 ... 125 knots)
0 ... 56 m/s (0 ... 124 mph, 0 ... 107 knots) virtually zero virtually zero
0.1 m/s (0.1 mph, 0.1 knots, 0.1 km/h)
±0.135 m/s (0.3 mph, 0.26 knots) or 3 % of reading, whichever is greater
Wind Direction
Measurement range
Starting threshold
0 ... 360° virtually zero
Delay distance virtually zero
Resolution 1°
Accuracy (wind speed over 1 m/s) ±2°
RS-232, RS422 or RS485, four different message formats adjustable from 1200 to 19200 bit/s
RS-232: 1 to 9 seconds
3 wires for ground, signal and supply fixed 1200 bit/s
1 to 3600 seconds
frequency
voltage output impedance simulated potentiometer reference voltage output impedance
10 kohm
0 ...V
ref represents 0 ... 359°
1.0 ... 4.0 V
24 kohm
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Wind Speed
Response Characteristics
Maximum reading rate
Sonic measurement time
Signal processing time
Response time
General
1 per second
0.2 s
0.15 s
0.35 s
Operating power supply
Heating power supply (for heated model)
Operating temperature
WS425 non-heated
10 ...15 VDC, 29 mA RMS
36 VDC
±10 %, 0.7 A
-40 ... +55 °C (-40 ... +131 °F)
WS425 heated -55 ... +55 °C (-67 ... +131 °F)
Material
body sensor arms transducer heads stainless steel silicone rubber and PVC
355 mm 250 mm 286 mm
Weight
WS425 stainless steel 1.7 kg (3.7 lbs)
Complies with EMC standard EN61326-1:1997 + Am1: 1998; Generic Environment
Accessories
Cable supporting analog outputs, 10 m
Cable supporting RS-232 outputs, 10 m
ZZ45204
ZZ452203
Cable supporting RS-485/422 outputs, 10 m 010411
Cable supporting SDI-12 outputs, 10 m WS425CABSDI
WS425FIX30 Adapter for 30 - 35 mm
(11/4") diameter vertical tube
Adapter for 60 mm
(21/4") diameter vertical tube
Field verifier
WS425FIX60
WS425VERIFIER
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Appendix A ________________________________________________________________Drawings
APPENDIX A
DRAWINGS
Figure 15 WS425FIX30 Adapter
0212-043
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Figure 16 WS425FIX60 Adapter
0301-012
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Appendix A ________________________________________________________________Drawings
0301-013
Figure 17 WS425FIX60 Adapter
The following numbers refer to Figure 17 above.
1 = Adapter tube
2 = Fastening clamp
3 = Fastening bolt
4 = Allen key
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Appendix A ________________________________________________________________Drawings
VAISALA _______________________________________________________________________ 85
www.vaisala.com
*M210361EN*
Advertisement
Key features
- Ultrasonic wind measurement technology
- Analog, SDI-12, and serial RS-232/422/485 modes
- On-board microcontroller for data processing
- Wind speed and direction measurement
- Adjustable averaging intervals and methods
- Wind direction coasting for low wind speeds
- Gust wind speed and direction calculations
- Upside down mounting capability
- Multiple serial communication protocols supported
