Operating Manual
Compact Weather Station
88
G. Lufft Mess- und Regeltechnik GmbH, Fellbach, Germany
18.6.8 Message Change of Unit System
The command is used to change the unit system used for the SDI12 data between metric
and US units. It is implemented as manufacturer specific X command.
Command:
aXU<u/m>!
Response
: aU<u/m><CR><LF>
u : US units, m: metric units
Example: change to metric units, SDI-
12 address ‘0’
0XUm!
0Um<CR><LF>
18.6.9 Message: Setting of the Averaging Interval Length
The avg, min, max and vct values of the measurement values are evaluated over a floating
interval with a length of 1 to 10 min. The length of this interval can be adjusted separately
for the groups temperature / humidity, air pressure and wind. (The averaging algorithm is not
applied to precipitation and compass).
Command:
aXA<t/p/w/r>+nn!
t : Temperature and Humidity
p: Air pressure
w: Wind
r: Global radiation
nn: Interval in minutes, valid range: 1 bis 10
Response:
aXA<t/p/w/r>+nn<CR><LF>
The response to the attempt of setting of an invalid interval length is
aXAf<CR><LF>
Example: Setting the interval for temperature and humidity to 5 minutes
0XAt+5!
0XAt+5<CR><LF>
18.6.10 Message: Setting of the Local Altitude
For the calculation of the relative air pressure the local altitude of the device is required.
Command:
aXH+nnnn!
nnnn: local altitude of the sensor in m
Response:
aXH+nnnn<CR><LF>
The response to the attempt of setting of an invalid altitude ( -100 < altitude < 5000) is
aXHf<CR<<LF>
Example: The altitude of the installation location is 135m above sea level
0XH+135!
0XH+135<CR><LF>