Owner's manual

R.M. Young Wind Sentry
7.4 Programming
This section is for users who write their own programs. A datalogger program
to measure this sensor can be created using Short Cut. You do not need to read
this section to use Short Cut.
7.4.1 Wind Speed
Wind speed is measured with the Pulse Count instruction (PulseCount() in
CRBasic and Instruction 3 in Edlog). Use the low level AC configuration.
For dataloggers programmed with Edlog, specify configuration code 21 to
output frequency in hertz.
The expression for wind speed (U) is:
U = MX + B
where
M = multiplier
X = number of pulses per second (Hertz)
B = offset
TABLE 7-3 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 hertz.
TABLE 7-3. Wind Speed Multiplier
(With Pulse Channel Configuration Set to Low Level AC, Output “Hz”)
Model Meters/Second Miles/Hour
03002 / 03101 M = 0.750
Off = 0.2
M = 1.677
Off = 0.4
*When the pulse channel configuration is set to Low Level AC, output
“counts”, the multiplier above is divided by the execution interval in seconds.
7.4.2 Wind Direction
The wind vane is coupled to a 10 kΩ potentiometer, which has a 8 degree
electrical dead band between 352 and 360 degrees.
The CR200(X) dataloggers use 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).
Excitation voltages, range codes, and multipliers for Campbell Scientific
dataloggers are listed in TABLE 7-4. Appendix B has additional information
on the BRHalf() measurement instructions.
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