Emerson Daniel 3415

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 4-8 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).
Updating chord proportion bin data values Equation 4-8:

ℎ
 + 1


ℎ

   1 + 
ℎ

Pr
ℎ
 + 1

Pr
ℎ

   1 + Pr
ℎ

where
Equation 4-8
AvgVel
ChordBin
n+1
=
chord bin (n+1)st average velocity (m/s)
AvgVel
ChordBin
n
=
chord bin nth average velocity (m/s)
NumVals =
update factor data point (dimensionless) (NumVals)
V
chord
=
chord velocity (m/s) (FlowVelA ... FlowVelD)
AvgProp
ChordBin
n+1
=
chord bin (n+1)st average proportion value (dimensionless)
AvgVel
ChordBin
n
=
chord bin nth average proportion value (dimensionless)
Prop
chord
=
chord proportion (dimensionless)
In the event of a chord failure with at least one operating chord, the meter's average
weighted flow velocity is estimated as shown in Equation 4-9.
Estimating average flow velocity using proportion values Equation 4-9:





  ℎ 

ℎ

  ℎ 
Pr
ℎ
where
Equation 4-9
V
AvgWtd
est
=
estimated average weighted flow velocity (m/s) (AvgWtdFlowVel)
V
Chord
=
(non-failed) chord velocity (m/s) (FlowVelA ... FlowVelD)
InterProp
chord
=
(non-failed) chord interpolated proportion value (dimensionless)
Measurement
Operations manual 25