Campbell Scientific PWS100 Present Weather Sensor - Manual (Page 128)

Appendix D. Software Flowchart
Determine
equivolumetric
diameter and
volume
Determine size
and velocity table
co-ordinates
Determine fuzzy
logic values for
size and velocity
Score particle
types from fuzzy
values
Identify particle
type or classify
unknown
Quality check
Determine total
precipitation
volume and rain
rate over period
Determine most
prevalent particle
type
Determine output
codes (WMO,
METAR, NWS) as
appropriate
Determine visibility
Store particle
type
Message interval limit
reached?
No
Yes
Store size,
velocity and
volume data
DSD Output
Shift zero
frequency
component to
centre of spectrum
Find maximum
value and position
of maximum
Select data width
for fitting
Shifted and mixed
multi-point data
interpolation
(polynomial fit)
Determine time
delay
Determine size
from velocity and
time delay values
Check cross correlation size
is within tolerance?
N
Y
Determine size
from transit time
channel 1 (uses
calculated
velocity)
Check transit time size is
within tolerance?
N
Y
Determine size
from signal
amplitude
L
M
A B C
I
Retrieve
average
correlation
velocity
value
Retrieve average
correlation
velocity value
F
J
Polycrystalline
End Processing
D-6