Wind Direction; Wind Vector Processing Instruction; Wind Speed Multiplier; Parameters For Wind Direction - Campbell 05103 User Manual

05103, 05103-45, 05106, 015108, 05108-45 and 05305 R.M. Young Wind Monitors

7.4.2 Wind Direction

Measurement
Range
Excitation 2500 mV
Voltage
Reverse
Excitation
Delay or
Settling Time
Multiplier
Offset

7.4.3 Wind Vector Processing Instruction

12
Table 7-2. Wind Speed Multiplier
Model
05103, 05103-45, or 05106
05108 or 05108-45
05305
The wind vane is coupled to a 10 k potentiometer, which has a 5 degree
electrical dead band between 355 and 360 degrees. A 1 M resistor between the
signal and ground pulls the signal to 0 mV (0 degrees) when wind direction is
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. Edlog
dataloggers (CR510, CR10X, CR23X) use Edlog Instruction 4—Excite, Delay
(P4).
Some CRBasic measurement sequences cause the measurement of the wind
direction to return a negative wind direction (–30º) while in the dead band. This
can be overcome by using a delay of 40 ms (40,000µs) or by setting negative wind
direction values to 0.0: If WindDir < 0, then WindDir = 0.0.
The excitation voltage, range codes, and multipliers for the different datalogger
types are listed in Table 7-3. Appendix B has additional information on the P4
and BRHalf() measurement instructions.
Table 7-3. Parameters for Wind Direction
CR300
CR200(X)
Series
NA mV 2500
2500 mV
NA NA
20000 µs 20000 µs
0.142 355
0 0
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) using the measured wind speed and direction samples.
Miles/ Metres/
Hour Output Second Output
0.2192 0.0980
0.3726 0.1666
0.2290 0.1024
CR800,
CR850,
CR1000X
CR1000
mV 2500 mV 5000
2500 mV 2500 mV
True True
20000 µs 20000 µs
355 355
0 0
CR5000,
CR3000
CR6
mV 5000 mV 5000
2500 mV 5000 mV
True True
20000 µs 20000 µs
355 355
0 0