Chapter 7 ___________________________________________________  Retrieving Data Messages
VAISALA______________________________________________________________________ 121
The structure of the pressure, temperature and humidity sensor response 
message:
S = Transducer id 1 type (wind speed)
0.2 = Transducer id 1 data (average wind speed)
M = Transducer id 1 units (m/s, average wind speed)
1 = Transducer id for average wind speed
S = Transducer id 2 type (wind speed)
0.2 = Transducer id 2 data (max wind speed)
M = Transducer id 2 units (m/s, max wind speed)
2 = Transducer id for max wind speed
* Checksum delimiter
57 = Two-character checksum for the response 
<cr><lf> = Response terminator
where
$ = Start of the message
WI = Device type (WI = weather instrument)
XDR = Transducer measurement response identifier
C = Transducer id 0 type (Temperature), see the 
following Transducer table
23.3 = Transducer id 0 data (Temperature)
C = Transducer id 0 units (C, Temperature)
0 = Transducer id for Temperature
C = Transducer id 1 type (temperature)
23.3 = Transducer id 1 data (Tp internal temperature)
C = Transducer id 1 units (C, Tp internal temperature)
1 = Transducer id for Tp internal temperature
H = Transducer id 0 type (Humidity)
50.1 = Transducer id 0 data (Humidity)
P = Transducer id 0 units (%, Humidity)
0 = Transducer id for Humidity
P = Transducer id 0 type (Pressure)
1009.1 = Transducer id 0 data (Pressure)