3410 Series Gas Ultrasonic Meters Operations Manual
Section 4: Flow measurement
3-9000-777 Rev E
January 2018
Average weighted flow velocity using chord proportions
27
When the meter has operated for a user-specified number of consecutive batches without any
chord failures, the meter updates each chord’s data values for the bin containing the chord
velocity as shown in
Equation 4-6
and sets the bin’s default indicator to FALSE. The
PropUpdtBatches
data point, configurable via the Daniel MeterLink
Edit/Compare Configuration
screen, specifies the number of consecutive failure-free batches required for updating the bin
data (range: [1, 1000], default: 24). The
NumVals
data point (that determines how quickly an
average value changes) is also configurable via the
Edit/Compare Configuration
screen (range:
[1, 1000], default: 10).
Equation 4-6 Updating chord proportion bin data values
where
=
chord bin (n+1)st average velocity (m/s)
=
chord bin nth average velocity (m/s)
=
update factor data point (dimensionless) (NumVals)
=
chord velocity (m/s) (FlowVelA ... FlowVelD)
=
chord bin (n+1)st average proportion value (dimensionless)
=
chord bin nth average proportion value (dimensionless)
=
chord proportion (dimensionless)
A
AvgVelChordBin
n 1
+
AvgVelChordBin
n
NumVals 1
–
(
)
⋅
Vchord
+
NumVals
------------------------------------------------------------------------------------------------------------------------------------
=
AvgPropChordBin
n 1
+
AvgPropChordBin
n
NumVals 1
–
(
)
⋅
Propchord
+
NumVals
--------------------------------------------------------------------------------------------------------------------------------------------------
=
AvgVelChordBin
n 1
+
AvgVelChordBin
n
NumVals
Vchord
AvgPropChordBin
n 1
+
AvgPropChordBin
n
Propchord
