Emerson Process Management 3422 用户手册

June 2013

3-9000-743 Rev S

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 

where

For each non-failed chord, the interpolated proportion value used in 

 is calculated 

as follows:

•

if the chord’s velocity is surrounded by trained (average velocity, average proportion) 
data pairs, then the interpolated proportion is the linear interpolation between the two 
data pairs

•

if the chord’s velocity has a trained (average velocity, average proportion) data pair on 
one side of it but not the other, then the interpolated proportion is the data pair average 
proportion

•

if there are no trained (average velocity, average proportion) data pairs, then the 
interpolated proportion is the corresponding bin’s default average proportion value

If all active chords fail, then the meter re-enters the Acquisition mode. If the 

VelHold data point 

is set to a value greater than zero, then, while in the Acquisition mode, the meter holds the 
average weighted flow velocity to the last good value for up to the 

VelHold number of batches 

before setting the velocity to zero. The 

VelHold default value is 0.

=

estimated average weighted flow velocity (m/s) 
(

AvgWtdFlowVel)

=

(non-failed) chord velocity (m/s) 
(

FlowVelA ... FlowVelD)

=

(non-failed) chord interpolated proportion value 
(dimensionless)

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