Campbell Scientific 034B-L Met One Windset - Manual (Page 19)

Met One 034B Wind Set
The expression for wind speed (U) is:
U = MX + B
where
M = multiplier
X = number of pulses per second (Hertz)
B = offset
TABLE 7-2 lists the multipliers (M) and offsets (Off) to obtain meters/second
or miles/hour when the Pulse Count instruction is configured to output the
result in Hz.
TABLE 7-2. Wind Speed Multiplier*
Model Meters/Second Miles/Hour
034B M = 0.7989
Off = 0.28
M = 1.787
Off = 0.63
*When configured to output counts, the multiplier above is divided
by the execution interval in seconds.
7.4.2 Wind Direction
The CR200(X) dataloggers use the ExDelSE() instruction to measure wind
direction. All other CRBasic dataloggers use the BRHalf() instruction (see
Appendix B, Example Program, for example).
Excitation voltages, range codes, and multipliers for our dataloggers are listed
in TABLE 7-3. The multiplier value converts the sensor’s millivolt output to
degrees. Appendix D has additional information on the measurement
instructions.
TABLE 7-3. Parameters for Wind Direction
CR800
CR1000
CR5000
CR3000 CR200(X)
Measurement
Range, Integration
2500 mV, 60 Hz,
reverse excitation
5000 mV, 60 Hz,
reverse excitation
N/A
Excitation Voltage 2500 mV 5000 mV 2500 mV
Multiplier 720 720 0.288
Offset 0 0 0
7.4.3 Wind Vector Processing Instruction
The Wind Vector output instruction is used to process and store mean wind
speed, unit vector mean wind direction, and standard deviation of the wind
direction (optional) from the measured wind speed and direction values.
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