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2150EX Area Velocity Flow Module
Section 3 Programming
3-5
3.3.3 No Velocity Data and
Flow Rates
Occasionally velocity readings are lost because either a flow
stream does not contain enough reflective particles, or the sensor
is covered with silt. These lost velocity readings are logged as a
“No Data Code.” If the 2150EX is set up to use area velocity flow
conversion, it is then unable to calculate the flow rate. You can
control how the Flow Rate readings will be reported during these
conditions with the “Set flow rate to zero if no velocity data”
checkbox, found on Flowlink’s
Velocity measurement tab.
• Checked, the 2150EX stores the flow rate as 0.0 when
velocity data is not available.
• Unchecked, the 2150EX will use the last valid velocity
measurement in the flow rate calculation.
Note
Measuring velocity becomes extremely difficult at low liquid
levels. When the level falls below one inch, the module no
longer measures the velocity. Instead, velocity is interpolated
based on measurements that occurred between one and
seven inches of liquid.
Prevent Velocity Signal
Interference If the AV Sensors of a multiple module site are placed near each
other it is important that each sensor receives its own trans-
mitted signal. To prevent this sort of interference, you can syn-
chronize the modules so that only one module may take a velocity
measurement at any given moment.
To synchronize the velocity measurements of a multiple module
site, check the
Prevent interference box found on the Velocity mea-
surement tab. You may leave this box unchecked for single
module sites or multiple module sites measuring velocities of
separate channels.
Note
The Prevent interference check box should always be selected
when using the 2150EX with LTC2191EX lithium battery
packs, to prevent overloading the fused outputs.
3.3.4 Flow Conversion
The 2150EX is capable of determining flow rates using either
area velocity conversion or level-to-flow rate conversion. Table
3-1 lists the available flow conversion methods
.
The 2150EX is capable of calculating and storing any two con-
version methods simultaneously. Flow conversions are defined on
the
Flow Rate and Flow Rate 2 measurement tabs in Flowlink.
To do this, select the Conversion Type that matches your appli-
cation, then enter the required parameters in the fields to the
right of the selected conversion type.