Wind Research 400 3-axis Ultrasonic Anemometer

The highly accurate Wind Research 400 3-axis ultrasonic anemometer is a powerful tool for serious wind and turbulence studies. With on-line turbulence calculations and the ability to connect additional sensors to produce a compact, portable station the Wind Research 400 is ideal for use as part of an eddy-flux station.

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Features

• separate measuring head and electronics which further reduces flow distortion and error
• up to 50 Hz sampling rate
• wind speed range 0.01 - 45 m/s (0 - 100 mph)
• digital and analogue outputs
• verifies and reports data quality
• 6 external sensor inputs with time delay capability for time-modulated data output
• 16 bit resolution on analogue inputs
• 4 analogue channel outputs (0 -10V)
• 2 x TTL and 2 x PT100 inputs
• on-line turbulence calculations
• battery power (9 - 36 VD) or mains (110-220 VAC) (mains adapter supplied)
• field calibration kit
• transport case

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What it does

The Wind Pesearch 400 provides the following information in various data outputs which can be polled or output automatically:

• instantaneous and averaged data for the three component wind vectors
• virtual temperature
• horizontal wind speed and direction plus vertical wind component
• chart mode (provides 0-540º wind direction and speed values)
• NMEA value outputs
• raw data mode (uncorrected) or 2D / 3D head corrected data

Data can be averaged by:

• scalar or vectoral
• clock synchronised or running average
• separate output rates and sampling times

Some other important features:

• user definable north orientation (range 0-359º alignment off axis)
• data quality control to perform confidence checks on raw data
• date / time stamps with several options
• check sum information
• calibration validity output monitoring

Near real-time turbulence calculations:

• mean wind components (3D) and temperature
• Standard Deviations (SD) of components and temperature
• covariances of different components and temperature
• SD values comparing mean wind to parallel component as well as the horizontally and vertically perpendicular wind component
• turbulence intensities
• friction velocity
• Drag coefficient
• Monin-Obukhov stability
• momentum and heat fluxes
• u, v, w
• direction and velocity mean components or values

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Examples of data output

Normal data example (instantaneous). Every data string starts with a header line that consists of the string SNC followed by a space and 12 characters for the date/time stamp, another space and finally the UTC string i.e.:

SNC 940815090015 UTC

x = 1.83 y = -0.79 z = 0.20 T = 20.17



If you order the optional on-line turbulence calculations you will also get turbulence data as per the following example:

The following lines display the averaged data using a fixed format: up to 4 values per line each preceded by its name (5 characters, right-aligned), a space character, an equals sign and an 8 character (right-aligned) floating point number with a fixed number of decimal digits (possibly with trailing zeros). This number will be replaced by 8 space characters in case of invalid data. The values are separated by a space character. The names of the data and their ordering can be understood from the following example:

SNC 940815090015 UTC AVE 600 SMP 10 AZI 0 SDQ 100 HTR

x = 1.74	y= -0.93	z = -0.14	T = 0.62
xsig = 0.91	ysig = 0.89	zsig = 0.43	Tsig = 0.47
xycov = -0.3911	xzcov = -0.2010	xTcov = -0.1801
yzcov = 0.0961	yTcov = 0.2170	zTcov = 0.1200
psig = 1.07	qsig = 0.70	rsig = 0.40
tp = 0.54	tq = 0.35	tr = 0.20
ustar = 0.39	Tstar = 0.31	Cd = 0.04
MOs = -0.03	mf = -0.19	hf = 144.60
u = -0.93	v = 1.74	w = -0.14
vel = 1.98	dir = 151.9

where:

AVE	the averaging time
SMP	the sampling rate in hertz
AZI	the devise azimuth
SDQ	the sonic data quality
HTR	informs the user that the sensor head heating is turned on
x	mean x wind component in the sensor related orthogonal co-ordinate system (parallel to the black arrow on the electronic box); unit m/s
y	mean y wind component in the sensor related orthogonal co-ordinate system (horizontally perpendicular to x); unit m/s
z	mean z wind component in the sensor related orthogonal co-ordinate system (vertical); unit m/s
T	mean temperature; unit ºC
xsig	standard deviation of x; unit m/s
ysig	standard deviation of y; unit m/s
zsig	standard deviation of z; unit m/s
Tsig	standard deviation of T; unit K
xycov	covariance of x and y; unit m2/s2
xzcov	covariance of x and z; unit m2/s2
xTcov	covariance of x and T; unit mK/s
yzcov	covariance of y and z; unit m2/s2
yTcov	covariance of y and T; unit mK/s
zTcov	covariance of z and T; unit mK/s
psig	standard deviation of the wind component parallel to the mean wind direction; unit m/s
qsig	standard deviation of the wind component horizontally perpendicular to the mean wind direction; unit m/s
rsig	standard deviation of the wind component vertically perpendicular to the mean wind direction; unit m/s
tp	longitudinal turbulence intensity
tq	transversal turbulence intensity
tr	vertical turbulence intensity
ustar	friction velocity u.; unit m/s
Tstar	characteristic temperature T.; unit K
Cd	drag coefficient Cd
MOs	Monin-Obukhov stability parameter; unit m-1
mf	vertical momentum flux; unit kg/ms2
hf	vertical heat flux; unit W/m2
u	mean west-east wind component (depends on setting of parameter AZ); unit m/s
v	mean south-north wind component (depends on setting of parameter AZ); unit m/s
w	mean vertical wind component; unit m/s
vel	mean horizontal wind velocity; unit m/s
	mean horizontal wind direction (depends on setting of parameter AZ); unit°

The following data strings will be displayed for the analogue inputs/counters:

2 x PT100 inputs	6 x analogue input channels	2 x TTL counters
e1 and e2	e3 to e8	c1 and c2
e1sig and e2sig	e3sig to e8sig
e1zco and e2zco	e3zco to e8zco

where:

2 x PT100 inputs
e1 and e2	mean Pt100 temperatures (based on a0, a1 values of the basic system); unit ºC
e1sig and e2sig	standard deviations of the Pt100 temperatures (based on a0, a1 values of the basic system); unit K
e1zco and e2zco	covariances of the Pt100 temperatures (based on a0, a1 values of the basic system) with z; unit Km/s
6 x analogue inputs
e3 to e8	mean values of the analogue input channels (based on a2 ... a7 values of the basic system); unit V
e3sig to e8sig	standard deviations of the analogue input channels (based on a2 ... a7 values of the basic system); unit V
e3zco to e8zco	covariances of the analogue input channels (based on a2 ... a7 values of the basic system) with z; unit Vm/s
2 x TTL counters	c1 and c2 Counted events (based on c0, c1 values of the basic system); unit 1

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Specifications of the Wind Research 400 3-axis ultrasonic anemometer
Wind Speed
Range	0.01 - 45 m/s (0 - 100 mph)
Accuracy	+/- 2 % (full scale output)
Resolution	0.01 m/s (steps)
Wind Direction
Range	0 - 359o or 0- 540o
Accuracy	+/- 2o
Resolution	0.4o (steps)
Digital Output
Type	RS232, RS422
Sampling rate	50 Hz
Averaging	up to 3600 seconds
Analogue Outputs x 4
Type	0-5 V, 0- 10 V, 0-20 mA, 4-20 mA
Resolution	12 bit
Scalable	Yes
Analogue Inputs x 6
Type	+/- 2.5 V, +/- 5 V, +/- 10 V
Resolution	16 bit
Sample delay option	Yes
PRT inputs	2
TTL inputs	2
PT100 inputs	2
Power
Requirements	9-36 VDC operation or 115 / 230 VAC (mains adaptor supplied)
Current draw	180 mA (@ 24 VDC
Data
Turbulence data	Yes (see above for more information)
Sonic temperature	with digital output -30oC to 50oC (-22oF to 122oF) in non-condensing environments with analogue output measures within a 40o span (user configurable) of the above range with a resolution of 0.01oC
Units of measure	m/s, knots, mph, km/h, oC
General
IP rating	IP65
Size	32 cm x 69 cm (12 x 27 inches)
Weight	7.1 kg (15 Ibs)
Materials:
sensor head	stainless steel (V4A)
electronic housing	powder-coated die-cast aluminium
Power and data cable	20 m (65 ft) power, data and analogue cable (8 m (26 ft) between the measuring head and electronics box and 12 m (39 ft) from electronics box)
Optional items	BiralView software

This range is in continuous development therefore specifications may change without prior notice. E&OE

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Contact Biral for more information

To find out more about this instrument or to discuss your application requirements please do not hesitate to contact Biral.

• wwwmet@biral.com or click the Make Request button below the product photograph
• telephone to 01275 847787 (from the UK) or +44 1275 847787 (International)

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After Sales Support

Biral offers free advice and technical support for the lifetime of the instruments we sell. Once you have purchased the unit you can contact us for help:

• wwwmetsupport@biral.com
• telephone to 01275 847787 (from the UK) or +44 1275 847787 (International)

Product Information

• Research 400 Specifications.pdf
• ultrasonic anemometer brochure.pdf

Scientific Papers and Articles

• Metek USA1.pdf