Values For Internal Monitoring; Table 24 Values From Sta Message For Internal Monitoring - Vaisala PWD22/52 User Manual

Appendix A ________________________________________________Values for Internal Monitoring
APPENDIX A

VALUES FOR INTERNAL MONITORING

Status Message Typical
AMBL
Ambient light -0 V
OFFSET
Measurement 140Hz...
signal offset. The
150Hz
lowest frequency
for measurement
signal
REC. BACKSCATTER
Measurement
signal from the
receiver
contamination
control circuit.
'CHANGE' value
is the instant
signal difference
to clean value.
VAISALA ______________________________________________________________________ 103
Typical values come from factory testing and are allowed to change
within the given Min/Max limits. Fault limits give hints for
troubleshooting.
Table 24 Values from STA message for Internal Monitoring
Min. / Max.
-9 V / +3 V
80 Hz /
170 Hz
Fault Description
> 3 V Preamplifier is
'RECEIVER not working.
ERROR'
< -9 V The sun is
'RECEIVER shining directly or
SATURATED' from reflecting
surface (snow
etc.) to the
receiver.
< 80 Hz Drifting may be
>170 Hz caused by other
'OFFSET disturbing
ERROR' optical sensors
nearby or other
interference
problems.
Rec.backscatter Rising value can
change (Instant be caused by
backscatter contamination of
minus clean
receiver optics,
backscatter) > snow inside the
alarm limit receiver hood,
'BACKSCATTER spider net in front
HIGH' of the hood etc.
Check the
contamination
limits also.
Action
Change
PWC22/52.
Check the
orientation of
PWD22/52.
1) Check
other parts of
STA
message.
2) If offset
does not
remain stable,
change the
control unit
PWC22/52.
Clean the
outside of
optical
surfaces and
remove
possible
disturbances
from optical
path.