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Meter Configuration
User Manual
3.8
AFC Manager ♦ Configuration Tool
Liquid and Gas Flow Computer
Meter Factor Linearization
Meters are mechanical instruments, so eventually they wear out. Over time, the
actual measured volume (the "gross volume") will tend to drift from the nominal
measured volume (the "indicated volume"). The factor that corrects "indicated" to
"gross" is called the "meter factor", and is a number very close to 1. The
procedure that is performed periodically to determine a (new) meter factor is
called "proving". A pulse type meter is "proved" periodically to ensure that the
meter performs as expected over a period of time.
A prover passes a known volume of product through the meter and compares the
volume indicated by the meter against the fixed volume of the prover (measured
with a high degree of precision). If the meter indicates the measured volume to
be exactly the same as the known prover volume, the Meter Correction Factor is
said to be equal to 1.00000 (Meter Factor = Prover Volume/Metered Volume).
Because meters are mechanical instruments, their behavior may differ depending
on the rate of flow through the meter. That is, the meter factor may depend on
the flow rate at which the measurement is performed. The AFC accommodates
this by allowing you to enter up to 5 factor-flowrate pairs (the "Meter Factor
Linearization" table); the AFC determines the meter factor to be used by linear
interpolation on this table from flow rate at operating conditions (Since flow rate
depends on the meter factor according to API, but meter factor depends on flow
rate according to the linearization table, the AFC performs a second iteration of
the interpolation in order to obtain an accurate meter factor).
Click the Meter Factor Curve Read button to transfer the current Meter Factor
Linearization configuration from the AFC module to the local PC
Page 78 of 267
ProSoft Technology, Inc.
March 2, 2011