Vaisala LT31 - Miscellaneous Problems

Chapter 7 ___________________________________________________________ Troubleshooting
VAISALA ______________________________________________________________________ 273
Miscellaneous Problems
Table 37 Miscellaneous Problems
Problem Probable Cause Remedy
Dialogue not operating Check cable connections, make reset.
Check the communication parameters
(default in RS-232/RS-485: 9600/8N1) and
the flow control parameters.
Check the cable connections.
To prevent collisions in half-duplex RS-485
bus, switch line feeds off from your terminal
software.
Wrong communication
parameters
If a modem is used, verify that the same
modem standard is used in both modems
and one is in the answer mode and the other
in the originate mode.
Wrong polling command used In the MITRAS and FLAMINGO emulation
modes, the LT31 answers only to MITRAS
and FLAMINGO polls, respectively.
Wrong data port Open the terminal program and the
command mode through the data or
maintenance line and give the PARAMETER
command. Check that the message port is
DATA and that the data port mode is the
desired one.
Data message is
missing
Sensor is off or out of power Check that the power switch is on and the
LEDs on the FSP102 power board are lit and
the status LED on the interface unit is
blinking. If the AC switch is on but no LED is
lit, check the fuses on the FSP102 board
and verify the presence of a line voltage.
Dots instead of data
message when
using Windows
HyperTerminal
Wrong font being used Select View and Font from the drop-down
menu, and click OK.
Wrong serial port on the host
computer
Check the serial port your terminal software
is using.
Command mode
does not open from
the maintenance
connector
Maintenance line cabling is
faulty
Try to open the command mode from the
data port (connect your computer into the
data port using the connectors on the
LTC212 front panel) to make sure LTC212 is
OK.
Visibility value
missing in the
message
Active alarm (measurement
value not reliable and not
shown)
Check which alarm is active and remove the
cause for the alarm.
Unit ID is set Use correct ID or the format OPEN * (or
OPEN LT) that opens the command line
regardless of the unit ID. Remove the unit ID
if not needed.
Check the communication parameters
(default in RS-232/RS-485: 9600/8N1) and
the flow control parameters.
Data messages
arrive but command
mode does not open
with the OPEN
command.
Wrong communication
parameters
To prevent collisions in half-duplex RS-485
bus, switch line feeds off from your terminal
software.