Emerson Daniel 3414 - Page 43

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)
AAvgVel
ChordBin
n1+
AvgVel
ChordBin
n
NumVals 1–()
⋅


V
chord
+
NumVals
----------------------------------------------------------------------------------------------------------------- -------------------=
AvgProp
ChordBin
n1+
AvgProp
ChordBin
n
NumVals 1–()
⋅


Prop
chord
+
NumVals
----------------------------------------------------------------------------------------------------------------- ---------------------------------=
AvgVel
ChordBin
n1+
AvgVel
ChordBin
n
NumVals
V
chord
AvgProp
ChordBin
n1+
AvgProp
ChordBin
n
Prop
chord