Campbell 03002, Руководство по эксплуатации продукта

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Table 7-4: Wind speed multiplier
(with pulse terminal 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 terminal configuration is set to Low Level AC, output “counts”,
the multiplier above is divided by the execution interval in seconds.
7.2.2 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. 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 352 and 360 degrees).
Wind direction is measured by 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 band. To overcome this problem, all
program examples use a delay of 20 ms (20,000 μs) and set any negative wind direction values to
0.0: If WindDir < 0, then WindDir = 0.0.
The excitation voltage, range codes, and multipliers for the different data logger types are listed
in
Table 7-5 (p. 10). Wind direction measurement theory (p. 23) has additional information on the
BRHalf()
measurement instruction.
Table 7-5: Parameters for wind direction
CR300
Series
CR800,
CR850,
CR1000
CR1000X CR6 CR3000
Measurement range mV2500 mV2500 mV5000 mV5000 mV5000
Excitation voltage 2500 mV 2500 mV 2500 mV 2500 mV 5000 mV
Reverse excitation NA True True True True
Delay or settling time 20000 µs 20000 µs 20000 µs 20000 µs 20000 µs
Multiplier 352 352 352 352 352
Offset 0 0 0 0 0
Wind Sentry Series 10