Xylem SonTek FlowTracker2, User Manual

Page: 105 / 308

SonTek – a Xylem brand
FlowTracker2 User’s Manual (January 2019)
104
6.4. Automated Beam Check
The Automated Beam Check function allows the user to perform a Beam Check in the
region of the measurement section before data collection starts. The automated beam
check perform a number of quality control checks on the data collected to determine if
the flow conditions are suitable for discharge measurements. The data that is displayed
graphically during the Automated BeamCheck is time series of the Quality Control
parameters.
The Automated BeamCheck is an automated version of Beam Check function
described in 6.3 Beam Check. In the Original FlowTracker, the Automated Beam
Check was known as “Auto QC Test”.
a) Place the probe in moving water such that the probe is submerged and well away
from any underwater obstacles,
i). The FlowTracker2 collects data until It has 20 diagnostic samples (not time
based),
ii). The beam data are analyzed on several criteria outlined in
Table 6:6
.
b) The automated beam check quality control criteria used in the evaluation of the
beam check data are listed in
Table 6:6
,
Table 6-6 - Automated Beam Check Quality Control Criteria
Quality Control Criteria QC Warning Graphic Display
Noise Level
•
Measured electronics noise
level is compared to reference
data. Any significant deviation
causes a warning,
•
A large change in noise level
may indicate damage to the
probe.
•
Noise level supplied in
Automated BeamCheck is
given in Counts. Multiply with
0.43 to convert to dB.
Noise Level >
QC
SNR
•
The SNR is checked as
sufficient for reliable data
collection,
•
Each beam SNR is compared
to be sure all beams perform
equally,
•
A warning is issued for low
SNR < 4 dB,
•
A warning is issued for 4 dB <
SNR <7dB,
•
Beam SNR values differ.
SNR