Campbell Scientific 034A-L User Manual
INSTRUCTION MANUAL
Met One 034A-L Windset
Revision: 7/97
Copyright (c) 1980-1997
Campbell Scientific, Inc.
Warranty and Assistance
The MET ONE 034A-L WINDSET is warranted by CAMPBELL
SCIENTIFIC, INC. to be free from defects in materials and workmanship under
normal use and ser vice for twelve (1 2) months from date of shipment unless
specified otherwise. Batteries have no warranty. CAMPBELL SCIENTIFIC,
INC.'s obligation under this warranty is limited to repairing or replacing (at
CAMPBELL SCIENTIFIC, INC.'s option) defective products. The customer
shall assume all costs of removing, reinstalling, and shipping defective products
to CAMPBELL SCIENTIFIC, INC. CAMPBELL SCIENTIFIC, INC. will
return such products by surface carrier prepaid. This warranty shall not apply
to any CAMPBELL SCIENTIFIC, INC. products which have been subjected to
modification, misuse, neglect, accidents of nature, or shipping damage. This
warranty is in lieu of all other warranties, expressed or implied, including
warranties of merchantability or fitness for a particular purpose. CAMPBELL
SCIENTIFIC, INC. is not liable for special, indirect, incidental, or
consequential damages.
Products may not be returned without prior authorization. The following
contact information is for US and International customers residing in countries
served by Campbell Scientific, Inc. directly. Affiliate companies handle repairs
for customers within their territories. Please visit www.ca mpbellsci.co m to
determine which Campbell Scientific company serves your country. To obtain
a Returned Materials Authorization (RMA), contact CAMPBELL
SCIENTIFIC, INC., phone (435) 753-2342. After an applications engineer
determines the nature of the problem, an RMA number will be issued. Please
write this number clearly on the outside of the shipping container.
CAMPBELL SCIENTIFIC's shipping address is:
CAMPBELL SCIENTIFIC, INC.
RMA#_____
815 West 1800 North
Logan, Utah 84321-1784
CAMPBELL SCIENTIFIC, INC. does not accept collect calls.
034A-L Table of Contents
PDF viewers note: These page numbers refer to the printed version of this document. Use
the Adobe Acrobat® bookmarks tab for links to specific sections.
1. General........................................................................1
2. Specifications .............................................................1
3. Installation...................................................................1
3.1 Siting.........................................................................................................1
3.2 Mounting...................................................................................................1
4. Wiring ..........................................................................2
5. Datalogger Programming...........................................3
6. Sensor Maintenance...................................................6
7. Long Lead Lengths.....................................................6
8. Wind Direction Measurement Theory........................8
8.1 AC Half Bridge (P5).................................................................................8
8.2 DC Half Bridge (P4).................................................................................8
9. References ..................................................................8
Appendix
A. Wind Direction Sensor Or ientation.......................A-1
A.1 Determining True North and Sensor Orientation.................................A-1
A.2 Prompts from GEOMAG.....................................................................A-2
Figures
3-1. 034A-L Mounted on a 019ALU Horizontal Crossarm............................2
4-1. 034A-L Windset Wiring Diagram........................................................... 3
8-1. 034A-L Potentiometer in a Half Bridge Circuit.......................................8
A-1. Magnetic Declination for the Contiguous United States.....................A-1
i
034A-L Table of Contents
Table
A-2. Declination Angles East of True North Are Subtracted from 0
to Get True North......................................................................... A-2
A-3. Declination Angles West of T rue North Are Added to 0
to Get True North......................................................................... A-3
5-1. Multipliers and Offsets for Wind Speed and Direction........................... 4
7-1. Multiplier and Offset for Wind Direction when using
Lead Lengths Greater than 200 Feet................................................6
ii
MET ONE 034A-L WINDSET
1. GENERAL
The Met One 034A-L Windset is an integrated
cup anemometer and wind vane. The
anemometer consists of three cups that sense
the wind speed. These cups rotate on a vertical
shaft that magnetically activates a sealed reed
switch. The read switch opens and closes at a
rate proportional to wind speed. The wind
direction is sensed by a vane. The vane drives a
10 kΩ potentiometer.
2. SPECIFICATIONS
Wind Speed
Operating Range: 0 to 49 m s
-1
Threshold: 0.4 m s
(0.9 mph)
Accuracy:
±0.12 m s
speed < 10.1 m s
±1.1% of reading for wind
speeds > 10.1 m s
-1
(±0.25 mph) for wind
-1
(22.7 mph)
-1
Output Signal: contact closure (reed switch)
Wind Direction
Range: 0 to 360°, shorting to ground between
356° to 360°
Threshold: 0.4 m s
-1
(0.9 mph)
Accuracy: ±4°
Resolution: 0.5°
Potentiometer Specifications:
Resistance: 0 to 10 kΩ shorting at crossover
General Specifications
Operating Temperature Range: -30° to +70°C
Weight: 907 g (2.0 lb.)
NOTE: The black outer jacket of the cable is
Santoprene® rubber. This compound was
chosen for its resistance to temperature
extremes, moisture, and UV degradation.
However, this jacket will support combustion in
air. It is rated as slow burning when tested
according to U.L. 94 H.B. and will pass
FMVSS302. Local fire codes may preclude its
use inside buildings.
-1
(0 to 110 mph)
(22.7 mph)
3. INSTALLATION
3.1 SITING
Locate wind sensors away from obstructions
(e.g. trees and building). As a general rule of
thumb there should be a horizontal distance of
at least ten times the height of the obstruction
between the windset and the obstruction. If it is
necessary to mount the sensors on the roof of a
building, the height of the sensors, above the
roof, should be at least 1.5 times the height of
the building. See Section 9 for a list of
references that discuss siting wind speed and
direction sensors.
3.2 MOUNTING
Tools Required:
• 5/64” and 1/16” allen wrenches
• compass and declination angle for the site
• small screw driver provided with datalogger
• UV resistance cable ties
• small pair of diagonal-cutting pliers
• 6 - 10” torpedo level
Mount the 019ALU crossarm to the top of the
tripod/tower. Orient the 019ALU north and
south with the 3/4 x 1 inch Nu-Rail on the north
end. Appendix A contains detailed information
on determining true north using a compass and
the magnetic declination for the site.
Remove the alignment screw at the base of the
034A-L (Figure 3-1). Insert the 034A-L into the
aluminum bushing provided with the sensor.
Align the hole in the bushing with that in the
034A-L base and replace the screw. Insert the
034A-L/bushing into the 3/4 x 1 inch Nu-Rail on
the 019ALU. Align the sensor so that the
counter weight points to true south and tighten
the set screws on the Nu-Rail. Remove the
shoulder screw to allow the vane to rotate.
1
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