Vaisala WXT510 - Manual (Page 136)

User’s Guide ______________________________________________________________________
134 _________________________________________________________________ M210470EN-D
for receiving data from several transmitters on the bus, just with a single
query command.
To generate different time slots, each WXT510 is given an individual
delay for its query response, by using the RS-485 line delay parameter
aXU,L. This parameter defines the time (in milliseconds) between the
last character of the query and the first character of the response from
WXT510.
Example (a bus with three WXT510s):
WXT510 #1 communication settings:
0XU,A=0,M=Q,C=3,I=0,B=4800,D=8,P=N,S=1,L=25
WXT510 #2 communication settings:
0XU,A=0,M=Q,C=3,I=0,B=4800,D=8,P=N,S=1,L=1000
WXT510 #3 communication settings:
0XU,A=0,M=Q,C=3,I=0,B=4800,D=8,P=N,S=1,L=2000
Now, when the XDR-query command $--WIQ,XDR*2D<cr><lf> is
sent, WXT510 #1 responds after 25 ms, WXT510 #2 after 1000 ms and
WXT510 #3 responds after 2000 ms. The sufficient delays depend on
the maximum number of characters in the response messages and the
baud rate. Note that all the transmitters are assigned with the same
address. Hence the data logger, after sending the query, shall sort out the
response messages on the basis of the individual response times.
To gain even more addressability transducer ID information provided in
the XDR response messages can also be used. If WXT510 address is set
to 0 (aXU,A=0) and all parameters are chosen except Rain peak
intensity and Hail peak intensity in the precipitation message, the
response to the XDR-query $--WIQ,XDR*2D<cr><lf> will be like:
$WIXDR,A,316,D,0,A,326,D,1,A,330,D,2,S,0.1,M,0,S,0.1,M,1,S,0.1,
M,2*57<cr><lf>
$WIXDR,C,24.0,C,0,C,25.2,C,1,H,47.4,P,0,P,1010.1,H,
0*54<cr><lf>
$WIXDR,V,0.000,I,0,Z,10,s,0,R,0.01,I,0,V,0.0,M,1,Z,0,s,1,R,0.0,M,
1*51<cr><lf>
$WIXDR,C,25.8,C,2,U,10.7,N,0,U,10.9,V,1,U,3.360,V,2*7D<cr><lf>
For the transducer IDs, see NMEA 0183 V3.0 Protocol on page 79 .