Velocity Edge DualX Service Manual Page 231

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Reference, Installation, and Operations Manual Section 6: Meter operation
3-9000-743 Rev U August 2014
Seniorsonic flow characterizations 205
The mass rate validity is indicated by the MassRateValidity data point (TRUE(1) indicates valid).
The mass rate is valid if the flow-condition volumetric flow rate is valid (indicated by
QFlowValidity where TRUE(1) indicates valid) and if the AGA8 flow-condition calculation is
valid (indicated by AGA8FlowCalcValidity where TRUE(1) indicates valid).
The mass rate is accumulated into the corresponding direction mass total regardless of the mass
rate validity.
The forward and reverse direction mass totals are each stored in non-volatile memory as a data
pair: a 64-bit unsigned integer portion and a 32-bit floating point fractional portion. For
example, a mass total of 12345.750 kg is stored as 12345 kg for the integer portion and
0.750 kg as the fractional portion. Note that while the mass rate can be positive (indicating
forward flow) or negative (indicating reverse flow), the mass totals are always positive values.
The non-volatile mass total data points are as listed in the table below:
6.1.14 Seniorsonic flow characterizations
For Daniel Mark III Ultrasonic Gas Flow Meter SeniorSonic meters only, the following flow charac-
terizations are calculated/estimated: symmetry, cross-flow, chord turbulence, profile factor, and
swirl angle. Alarm limits are provided for the chord turbulence and swirl angle values.
Symmetry
Symmetry is a dimensionless measure of the flow symmetry comparing the upper chords to the
lower chords and is readable via the Symmetry data point. Ideally the Symmetry should be 1.0.
Cross-flow
Cross-flow is a dimensionless measure of the flow symmetry comparing the chords on one side
of the meter to the chords on the other side. It is readable via the CrossFlow data point. Ideally
the Cross-flow should be 1.0.
Chord turbulence
Chord Turbulence is a estimate of the turbulence (percentage) at a chord location. A value is
calculated for each active chord and is readable via the TurbulenceA, TurbulenceB,
TurbulenceC, or TurbulenceD data points. A value of 0% indicates no appreciable turbulence.
Table 6-5 Mass Total Data Points
Forward direction Reverse direction
Integer Fraction Integer Fraction
PosMass PosMassFrac NegMass NegMassFrac
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