Communication protocol – Vaisala WXT520 User Manual
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User’s Guide ______________________________________________________________________
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Communication Protocol
Set the communication protocol SDI-12 v 1.3 (aXU,C=1,M=S) or SDI-
12 v1.3 continuous (aXU,C=1,M=R).
WXT520s on the bus shall be assigned with different addresses (for
example: aXU,A=0,1,2, ... ). Thereafter WXT520s on the bus do not
respond to the commands not assigned to them nor to the data messages
sent by the other WXT520s.
Example (A bus with three WXT520s):
WXT520 #1 communication settings:
0XXU,A=0,M=S,C=1,B=1200,D=7,P=E,S=1, L=25
WXT520 #2 communication settings:
1XXU,A=1,M=S,C=1,B=1200,D=7,P=E,S=1, L=25
WXT520 #3 communication settings:
2XXU,A=2,M=S,C=1,B=1200,D=7,P=E,S=1, L=25
If simultaneous measurements of the different units are needed, Start
concurrent measurement commands aC and aCC should be use for all
devices. If the measurements are to be performed consecutively for only
one unit at time, in addition to these also Start measurement commands
aM and aMC can be used. Start continuous measurement commands
aR1, aR2, aR3, aR5, aR, aRC1, aRC2, aRC3, aRC5 and aRC
available only in SDI-12 continuous protocol (aXU,M=R) can be used
eiher for simultaneous measurements of the units or consecutive
measurements for one unit at time. See also