Vaisala WXT520 - Manual (Page 136)

User’s Guide ______________________________________________________________________
134 _________________________________________________________________ M210906EN-C
Table 10 Communication Problems
Problem Possible causes Action(s)
No response to any commands. Wrong wiring or operation
voltage not connected.
Baud rate/start bits/parity/stop bit
settings do not match between
the device and the host.
Check the wiring and operation
voltage, see
Chapter 5, Wiring
and Power Management, on
page 43
.
Connect the service cable, use
the communication settings
19200,8 N,1. Check the serial
port settings of the device with
Configuration Tool or with
terminal program. Use command
aXU! (SDI-12) or aXU<cr><lf>
(ASCII/NMEA). Change the
values if needed. A software/
hardware reset is needed to
validate the changes.
When you have no service
cable, try typing address query
commands ?! and ?<cr><lf>
with different serial settings in
terminal program. When the
communication parameters
match, the device responds with
its address. The settings can
now be changed using aXU!
(SDI-12) or aXU<cr><lf> (ASCII/
NMEA) commands. A software/
hardware reset is needed to
validate the changes.
Incorrect <cr><lf> settings in the
terminal program. In ASCII and NMEA protocols
both <cr> and <lf> are required
after each command. Check that
your terminal program sends
both when pressing enter.
Connection works but data
messages not available. Wrong device address in a SDI-
12 command or a mistyped SDI-
12 command (in SDI-12 a
mistyped command is in no way
responded).
A command mistyped in ASCII/
NMEA mode while error
messaging/text messages is
disabled (aSU,S=N). Request the device address with
?! command and then retype the
command now with the correct
address. Check the data query
commands from
Chapter 7,
Getting the Data Messages, on
page 65
.
Enable the error messaging
using the Vaisala Configuration
Tool or any terminal by setting
aSU,S=Y, then try the command
again.