Vaisala WXT520 - Manual (Page 100)

User’s Guide ______________________________________________________________________
98 __________________________________________________________________ M210906EN-C
The checksum to be typed in the query depends on the device identifier
characters and can be asked from WXT520, see example below.
Example:
Typing the command $--WIQ,XDRxxx<cr><lf> (xxx arbitrary
characters) WXT520 responds
$WITXT,01,01,08,Use chksum 2D*72<cr><lf>
indicating that 2D is the correct checksum for the $--WIQ,XDR
command.
If there are several distinct measurements of the same parameter
(according to the transducer table below), they are assigned with
different transducer ids. For example, minimum, average and maximum
wind speed are measurements of the same parameter (wind speed) so if
all three are configured to be shown in the XDR message, they get
transducer ids A, A+1 and A+2, respectively, where A is WXT520
address aXU,A. The same applies for the wind direction. Temperature,
internal temperature and heating temperature have the same unit, thus
they are assigned with transducer ids A, A+1 and A+2, respectively.
Accumulation, duration and intensity for rainfall and hails are
measurements of the same parameters so they get transducer ids A for
rainfall and A+1 for hails. Rain and hail peak intensities are assigned
with transducer ids A+2 and A+3, respectively.
For example, for a WXT520 with device address 0 the transducer ids of
all the measurement parameters are as follows:
1. NMEA-format transmits only numbers as transducer ids. If WXT520
address is given as a letter, it will be shown as a number (0 ... 9, A = 10,
B = 11, a = 36, b = 37 etc.)
Table 7 Transducer IDs of the Measurement Parameters
Measurement Transducer ID
Wind direction min 0
Wind direction average 1
Wind direction max 2
Wind speed min 0
Wind speed average 1
Wind speed max 2
Pressure 0
Air temperature 0