Vaisala LT31 - Page 264

User's Guide ______________________________________________________________________
264 _________________________________________________________________ M210667EN-C
C2:Transmitter
Measurement CPU
LTC112; window
receiver AC
overrange
Window receiver signal is greater
than overrange threshold while
window transmitter LED driver is
detected as faulty.
Check derating and intensity value for
window transmitter module (wTdera, wTint)
(see section Service on page 250).
Repl
ace window transmitter module (see
section Replacing Window Transmitter
Module on p
age 213).
C3:Transmitter
Measurement CPU
LTC112; window
receiver AC
overrange
Window receiver signal is greater
than overrange threshold while
window transmitter LED driver is
detected as OK.
Replace transmitter measurement CPU
(see section Replacing Measurement
CPU/
Window Receiver on page 211).
C5:Receiver
Measurement CPU
LTC112; window
receiver AC
overrange
Window receiver signal is greater
than overrange threshold while
window transmitter LED driver is
detected as faulty.
Check derating and intensity value for
window transmitter module (wTdera, wTint)
(see section Service on page 250)
Repl
ace window transmitter module (see
section Replacing Window Transmitter
Module on p
age 213).
C6:Receiver
Measurement CPU
LTC112; window
receiver AC
overrange
Window receiver signal is greater
than overrange threshold while
window transmitter LED driver is
detected as OK.
Replace receiver measurement CPU (see
section Replacing Measurement
CPU/
Window Receiver on page 211).
L1:LM21; indication
of abnormal situation
LM Sensor has detected a hood
or dew heater problem.
Refer to LM21 User's Guide.
L2:LM21; alarm ->
BGL not valid
LM Sensor has detected at least
one of the following situations:
- the sensor does not react to
changes in luminance
- field calibrator has been applied
- backscatter signal has increased
Refer to LM21 User's Guide.
L3:LM21; error ->
BGL not valid
LM21 Sensor has detected a
memory error
Refer to LM21 User's Guide.
L4:LM21; not
responding
LM21 sensor does not respond to
LT31 system polling request
Check whether the LM Sensor lines (power,
RS–485) are connected properly (see
section Mounting Optional LM21 on page
98).
LM sen
sor is not foreseen at all, but LM
Sensor is configured to be available (refer
to Table 11 on page 150).
L5:LM21; not
installed
LM Sensor is configured to be not
available (refer to Table 11 on
page 150).
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