Vaisala WXT530 Series - RS-485 Wiring; RS-485 Communication Protocol

1XU,A=1,M=P,C=3,I=0,B=19200,D=8,P=N,S=1,L=25
WX
T530 #3 communication settings:
2XU,A=2,M=P,C=3,I=0,B=19200,D=8,P=N,S=1,L=25
Example (
composite data message queries to the sensors 1 and 3 are assigned as
follows):
0R0<cr><lf>
1R0<cr><lf>
2R0<cr><lf>
A.3.4 NMEA 0183 v3.0, Query
The NMEA 0183 query messages do not contain device address information. Individual
query c
ommands can thus not be dir
ected to dierent transmitters. Instead, a specific time
slot method can be used f
or receiving data from several transmitters on the bus, just with a
single query command.
To generate dierent time slots, each transmitter 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 fr
om the transmitter.
Example (a bus with three transmitters):
WXT530 #1 communication settings:
0XU,A=0,M=Q,C=3,I=0,B=4800,D=8,P=N,S=1,L=25
WX
T530 #2 communication settings:
0XU,A=0,M=Q,C=3,I=0,B=4800,D=8,P=N,S=1,L=1000
WX
T530 #3 communication settings:
0XU,A=0,M=Q,C=3,I=0,B=4800,D=8,P=N,S=1,L=2000
Appendix A – Networking
173
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