Chapter 5 ________________________________________________________________ Operation
VAISALA ______________________________________________________________________ 173
The byte shown in Table 33 below indicates the status of the PWD
forward scatter sensor which is mounted to the transmitter support unit
LTS111 of the LTT111 (LT31 transmitter).
Table 33
LT31 PWD Status (Byte Number 40)
Code Explanation
Comment
0 OK
I Indication
of
abnormal
situation
Cleaning required.
W Warning
Hardware
warning.
A
Alarm
Immediate cleaning required.
E Error
Hardware
error.
C Communication
error
Device not responding.
X
Not configured
LT31 is not configured to handle
PWD (auto-calibration is off).
The byte shown in Table 34 below indicates the status of the LM21
Background Luminance Sensor which is optionally connected to the
receiver interface unit LTI211.
Table 34
Background Luminance Sensor LM21 (optional)
Alarm Status Information (Byte Number 54)
Code Explanation
Comment
0 OK
I Indication
of
abnormal
situation
Hood or dew heater problem.
A
Alarm
Sensor does not react to changes
in luminance.
LM21 has detected the field
calibrator LMA21.
Backscatter has increased.
E Error
Memory
error.
C Communication
error
Device not responding.
X
Not configured
LT31 is not configured to handle
LM21.