3410 Series Gas Ultrasonic Meters Operations Manual
Section 5: Calibrate and configure the meter
3-9000-777 Rev E
January 2018
Third-order polynomial
47
5.1.4
Third-order polynomial
When the Polynomial wet calibration method is selected, the meter uses a third-order
polynomial on the dry-calibration velocity
Equation 5-4
.
Equation 5-4 Wet calibration - third-order polynomial
where
If selecting “Polynomial Coefficients”, the “C” calibration coefficients are applied.
Figure 5-4 Calibration - Meter Factor: Polynomial
=
wet-calibration gas flow velocity (m/s) (
AvgFlow
)
=
dry-calibration gas flow velocity (m/s) (
DryCalVel
)
=
wet-calibration 0
th
order coefficient (m/s) (
FwdC0
or
RevC0
)
=
wet-calibration 1
st
order coefficient (dimensionless) (
FwdC1
or
RevC1
)
=
wet-calibration 2
nd
order coefficient (s/m) (
FwdC2
or
RevC2
)
=
wet-calibration 3
rd
order coefficient (s
2
/m
2
) (
FwdC3
or
RevC3
)
V
WetCal
C
0
C
1
V
+
DryCal
C
2
V
DryCal
2
C
3
V
DryCal
3
+
+
=
V
WetCal
V
DryCal
C
0
C
1
C
2
C
3
