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MODEL 81000
ULTRASONIC ANEMOMETER
1.0 SPECIFICATION SUMMARY
WIND SPEED
Range:
0 to 40 m/s (0 to 90 mph)
Resolution:
0.01 m/s
Threshold:
0.01 m/s
Accuracy:
±1% rms ±0.05 m/s (0 to 30 m/s)
±3% rms (30 to 40 m/s)
WIND DIRECTION
Azimuth Range:
0.0 to 359.9 degrees
Elevation Range:
±60.0 degrees
Resolution:
0.1 degree
Accuracy:
±2° (1 to 30 m/s)
±5° (30 to 40 m/s)
SPEED OF SOUND
Range:
300 to 360 m/s
Resolution:
0.01 m/s
Accuracy:
±0.1% rms ±0.05 m/s (0 to 30 m/s wind)
SONIC TEMPERATURE
Range:
-50 to +50 ºC
Resolution:
0.01 ºC
Accuracy:
± 2 ºC (0 to 30 m/s wind)
GENERAL
Air sample column:
10 cm high X 10 cm diameter
Air sample path:
15 cm
Internal sample rate: 160 Hz
Output sample rate: 4 to 32 Hz (selectable)
Output formats:
Serial data (selectable)
4 voltage output channels 0 to 4000 mV
RS-232 full duplex
RS-485 half duplex (can be bussed)
Baud Rates:
1200 to 38400
Power Supply:
12 to 30 VDC, 4 watts
Dimensions:
Overall height 56 cm
Support arm radius 17 cm
Mounting 34 mm (1.34 in) diameter
(standard 1 inch pipe)
Weight:
Sensor weight 1.7 kg (3.8 lb)
2.0 INTRODUCTION
The Young Model 81000 measures three dimensional wind veloc-
ity based on the transit time of ultrasonic acoustic signals. From
speed of sound, sonic temperature is derived. Speed of sound and
sonic temperature are corrected for crosswind effects.
Measurement data are available as voltage output signals or serial
output using RS-232 or RS-485 connections. Both voltage and
serial output may be configured for various of output formats.
Operating parameters may be edited using ordinary terminal soft-
ware on a PC. Simple menus make it easy. All parameters are
stored in nonvolatile memory.
Superior environmental resistance is achieved by using UV stabi-
lized thermoplastic, stainless steel, and anodized aluminum com-
ponents. Electrical connections are made via an easily accessible
junction box. The unit mounts on standard 1 inch pipe, outside
diameter 34mm (1.34").
3.0 INITIAL CHECKOUT
Carefully unpack the unit and inspect for physical damage. Any
damage should be reported to the shipper. The 81000 arrives fully
calibrated and ready to use. A simple four-step operational check
may be performed as follows:
1. Remove junction box cover. Connect power and signal wires to
terminals as indicated in wiring diagram for "RS-232 output.
Connect serial cable to computer COM port.
2. Start an ordinary serial communications program (like Hyper-
Term) with baud rate at 38400 and flow control set to NONE.
3. Apply power to the 81000 sensor. There will be a brief delay for
initialization then the unit will begin to output data at four times per
second using the following format: speed (m/s) azimuth (deg)
elevation (deg) speed-of-sound (m/s) sonic-temperature (°C).
Verify that all values are present on the display. Typical output
is shown below:
0.00
0.0
0.00
0.0
0.00
0.0
0.00
0.0
0.00
0.0
0.00
0.0
0.00
0.0
0.00
0.0
A threshold level of 0.2 m/s is preset from the factory. Wind below
the threshold, such as in still air, is output as 0.00 m/s. Azimuth
may be any value from 0.0 to 359.9 degrees. When wind speed
is below threshold level, azimuth output is maintained at the last
value read before the wind went below threshold. Elevation
remains zero until threshold is exceeded. Speed of sound ranges
from 300 m/s to 360 m/s depending on temperature. At 20°C the
value is about 344 m/s. Sonic temperature may be compared to a
standard Celsius thermometer and should agree within ±2°C. If
values appear questionable or any value is not displayed, remove
power and check all wiring connections. If the problem cannot be
corrected contact your YOUNG representative.
4. Verify sensor response by gently blowing through the measuring
section. Wind from the north side (marked "N"), should produce a
positive SPEED response and an AZIMUTH display correspond-
ing to North (i.e.: values around 359.9 or 0.0 ). Wind from the
opposite direction should produce values indicating south,
(around 180.0) and so forth. Downward wind produces negative
ELEVATION values, upward wind produces positive values.
1 .
0.0 346.70
25.14
0.0 346.68
25.11
0.0 346.76
25.25
0.0 346.80
25.30
0.0 346.76
25.25
0.0 346.80
25.30
0.0 346.80
25.30
0.0 346.82
25.35
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