LI-COR LI7200RS, Instruction Manual

Page: 69 / 226

Type Units
Other Other, m/s, cm/s, volts, K, and C
U m/s, cm/s, volts
V m/s, cm/s, volts
W m/s, cm/s, volts
Ts K, C, volts
SOS m/s, cm/s, volts
3
Enter the
Label
.
The Label will appear in the file header in both the data and/or metadata files. The
label cannot be changed for any of U, V, W, T
s
, or SOS. The label can be entered
only when ‘Other’ is selected.
Slope and Offset Examples
The units selected for each auxiliary input determine the
units label
recorded in the
data file header, as well as the file header in the metadata file used with EddyPro.
As such, it is important to convert the anemometer output from voltage to data
using the multiplier and offset.
For example, if you have configured your sonic anemometer to output U, V, and W
values in volts, but want the data file and metadata file to record these values in
m/s, you will need to set the multiplier and offset values to rescale the data.
The following table gives the appropriate values for m (multiplier) and b (offset) to
be used when converting raw voltages into units of m/s, using the default sonic
anemometer output ranges of -30 to +30 m/s for U and V, -5 to +5 m/s for W, and
-40 °C to 70 °C (and speed of sound 300 to 370 m/s).
U, V
-30 to +30 m/s
W
-5 to +5 m/s
T
s
-40 to 70°C
SOS
300 to 370 m/s
Sonic output (V)
m b m b m b m b
0-5V 12 -30 2 -5 22 -40 14 300
±5V 6 0 1 0 11 15 7 335
±2.5V 12 0 2 0 22 15 14 335
Example 1: You have configured the Gill WindMaster to output raw voltages for
auxiliary input U over the range of 0 to 5 V, and over a full scale wind speed of -30
to +30 m/s. You want to convert the raw voltages to wind speed and output the
Section 3. Operation
3-27 Entering Anemometer Information