Xylem SonTek FlowTracker2, User Manual

Page: 49 / 308

SonTek – a Xylem brand
FlowTracker2 User’s Manual (January 2019)
48
Std Error Threshold 3.4.3.2
The Standard Error Threshold parameter is a maximum threshold placed on the
Standard Error of velocity measurements.
a) Standard error of velocity (
σV
) is a direct measure of the accuracy of the mean
velocity data.
b) The default Standard Error Threshold applied in FlowTracker2 is 0.01m/s.
c) To change the Standard Error Threshold,
i). Use the backspace key to clear current entry,
ii). Type in the new value using the keypad.
d) To DISABLE the Standard Error Threshold,
i). Use the backspace key to clear current entry until “Disabled” is displayed.
Spike Threshold 3.4.3.3
The Spike Threshold parameter is the maximum threshold placed on the percentage of
spikes within a measurement.
a) Spikes in velocity data occur with any acoustic Doppler velocity sensor such as
the FlowTracker. Spikes may have a variety of causes – large particles, air
bubbles, or acoustic anomalies.
b) The default Spike Threshold applied in FlowTracker2 is 10%.
c) To change the Spikes Threshold,
i). Use the backspace key to clear current entry,
ii). Type in the new value using the keypad.
d) To DISABLE the Spikes Threshold,
i). Use the backspace key to clear current entry until “Disabled” is displayed.
Velocity Angle for Warning 3.4.3.4
The Velocity Angle for Warning parameter is the maximum threshold placed on the
velocity angle towards the probe.
a) An angle of 0
°
means flow direction is perpendicular to the tag line (as desired for
an ideal measurement location).
b) The default Velocity Angle for Warning applied in FlowTracker2 is 20 degrees.
c) To change the Velocity Angle for Warning,
i). Use the backspace key to clear current entry,
ii). Type in the new value using the keypad.
d) To DISABLE the Velocity Angle for Warning,
i). Use the backspace key to clear current entry until “Disabled” is displayed.