Vaisala LT31 - Page 270

User's Guide ______________________________________________________________________
270 _________________________________________________________________ M210667EN-C
T11:Transmitter
Window Transmitter
LTL212; LED aged
The derating value of the Window
Transmitter LED has been
evaluated as to be high.
Replacement of the Window Transmitter
Module in mid–term range (see section
Replacing Window Transmitter Module
on
page 213).
T12:Transmitter
Window Transmitter
LTL212; LED error
The derating value of the Window
Transmitter LED has been
evaluated as to be too high.
Replacement of the Window Transmitter
Module (see section Replacing Window
Tran
smitter Module
on page 213).
T13:Transmitter
Measurement CPU
LTC112; window
receiver DC high
T14:Transmitter
Measurement CPU
LTC112; window
receiver saturated
A light source other than the
modulated transmitter signal is
detected at Window Receiver.
Either the signal is detected as
high (T12) or the receiver is
saturated (T14).
Try to identify an additional light source of
any nature that might be in sight of the
Window Receiver. Try to eliminate the
influence.
T15:Transmitter
Measurement CPU
LTC112; window
receiver AC off
Window Receiver Signal is lower
than the underrange level.
During start-up this event is generated as
the averaging is not complete.
Check whether the optical light path at the
V-shaped windows at Transmitter
Measurement Unit (LTM112) is blocked.
T16:Transmitter
Measurement CPU
LTC112; window
receiver AC high
-
T17:Transmitter
Measurement CPU
LTC112; window
receiver AC
overrange
Window Receiver Signal is higher
than expected for normal
operation
Check window transmitter module status
(event T7 - T12). If any of the T7 - T12 are
reported, handle them first. If no such
event is reported, replace the Transmitter
Measurement CPU (see section Replacing
Measurement
CPU/Window Receiver on
page 211).
T18:Transmitter
Optics Unit LTO112;
alignment
mechanism vertical
underrange
T19:Transmitter
Optics Unit LTO112;
alignment
mechanism vertical
overrange
Position values are out of range
for normal operation.
Check if movement of all axes is possible
and position values are valid (see section
Service on page 250).
Che
ck for proper cabling at the Transmitter
Optics Unit.
Check for firm fit of eccentric to gear motor
axis and variable resistor axis.