Operating Manual    Smart Weather Sensor 
132  G. Lufft Mess- und Regeltechnik GmbH, Fellbach, Germany   
19.8.4  Message Format for Measurement Data MWD 
The P9 / PP measurement data transmission can be optionally extended by a MWD 
sentence containing wind data. The MWD sentence follows the definition for NMEA WI 
(weather instrument) messages. 
This option can be activated or deactivated by the GW command. 
The JW command selects between spot value and average value output of wind data. 
The message is field oriented, with variable length. The fields are separated by ','. 
 
Message format: 
$hhhhh, aaa.a,T,bbb.b,M,cc.c,N ,dd.d,M <CR><LF> 
 
$hhhhh   Message header, default $WIMWD (WI : Talker identifier “weather 
    instruments”, MWD: sentence identifier “wind measurements”) *) 
,     separator 
aaa.a     wind direction in °” 
,     separator 
T     identifier “True North” 
,     separator 
bbb.b     wind direction in ° 
,     separator 
M     identifier “Magnetic Nord” 
,     separator 
cc.c     wind speed in knots 
,     separator 
N     unit: kts 
,     separator 
dd.d    wind speed in m/s 
,     separator 
M     unit: m/s 
<CR><LF>   sentence terminator 
 
*) The message header can be modified. The MWD sentence uses the same talker ID as the 
XDR sentence, which can be modified by the UMB config tool or the XDR setting command 
NH. The leading '$' is and the identifier MWD are fixed and can not be modified 
**) here wind direction “true” and wind direction “magnetic” are identical.