Values For Internal Monitoring; Table 27 Values From Sta Message For Internal Monitoring - Vaisala PWD22 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
VAISALA _______________________________________________________________________ 111
The Typical values come from factory testing and are allowed to
change within the given Min/Max limits. The Fault limits give hints
for troubleshooting.
Table 27 Values from STA message for Internal Monitoring
Min. / Max. Fault
-9 V / +3 V > 3 V
'RECEIVER
ERROR'
< -9 V
'RECEIVER
SATURATED'
80 Hz / < 80 Hz
170 Hz >170 Hz
'OFFSET
ERROR'
Rec.backscatter
change (Instant
backscatter
minus clean
backscatter) >
alarm limit
'BACKSCATTER
HIGH'
Description Action
Preamplifier is Change
not working. PWC22.
The sun is Check the
shining directly or orientation of
from reflecting PWD22.
surface (snow
etc.) to the
receiver.
Drifting may be 1) Check
caused by other other parts of
disturbing STA
optical sensors message.
nearby or other 2) If offset
interference does not
problems. remain stable,
change the
control unit
PWC22.
Rising value can Clean the
be caused by outside of
contamination of optical
receiver optics, surfaces and
snow inside the remove
receiver hood, possible
spider net in front disturbances
of the hood etc. from optical
Check the path.