Wind Monitor Series
12
import
Short Cut
code into
CRBasic Editor
to create or add to a customized
program, follow the procedure in Appendix
(p. A-1)
. Programming basics for CRBasic dataloggers are
provided in the following sections. Complete program examples for select
CRBasic dataloggers can be found in Appendix
(p. B-1)
.
Programming basics and programming examples for Edlog dataloggers are
provided at
www.campbellsci.com\old-manuals
7.4.1 Wind Speed
For CRBasic dataloggers, wind speed is measured using the
PulseCount()
instruction. Syntax of the the
PulseCount()
instruction is:
PulseCount(
Dest, Reps, PChan, PConfig, POption, Mult, Offset
The
PConfig
parameter should be set to
1 (Low Level AC)
and the
POption
parameter should be set to
1 (Frequency)
.
The expression for wind speed (U) is:
U = Mx + B
where
M = multiplier
x = number of pulses per second (Hertz)
B = offset
lists the multipliers to obtain miles/hour or meters/second when
the measurement instruction is configured to output Hz.
The helicoid propeller has a calibration that passes through zero, so the offset is
zero (Gill, 1973; Baynton, 1976).
TABLE 7-2. Wind Speed Multiplier
Model
Miles/
Hour Output
Meters/
Second Output
05103, 05103-45, or 05106
0.2192
0.0980
05108 or 05108-45
0.3726
0.1666
05305
0.2290
0.1024
7.4.2 Wind Direction
The wind vane is coupled to a 10 kΩ potentiometer, which has a 5 degree
electrical dead band between 355 and 360 degrees. A 1 MΩ resistor between
the signal and ground pulls the signal to 0 mV (0 degrees) when wind direction
is in the dead band (between 355 and 360 degrees).
The CR200(X) datalogger uses the
ExDelSE()
instruction to measure wind
direction. All other CRBasic dataloggers use the
BRHalf()
instruction.
Some CRBasic measurement sequences can cause the measurement of the
wind direction to return a negative wind direction (–30º) while in the dead
Summary of Contents for Wind Monitor Series
Page 2: ......
Page 6: ......
Page 24: ...Wind Monitor Series 16...
Page 26: ...Appendix A Importing Short Cut Code Into CRBasic Editor A 2...
Page 30: ...Appendix B Example Programs B 4...
Page 34: ...Appendix C Wind Direction Sensor Orientation C 4...
Page 36: ...Appendix D Wind Direction Measurement Theory D 2...
Page 37: ......
