Functional Description
Flow Computer Tasks
10-2 AutoPILOT PRO Flow Computer User Guide
Thermo Fisher Scientific
The differential meter calculations are run once per second for all meter
runs. Users may select from the following for differential type meters:
AGA 3 / ASTM 2530-1992
AGA 3-1985
GOST
V-Cone
Annubar
Slotted-DP
Linear meter calculations are run once per second for all meter runs. Per
AGA 7 and AGA 9, the equation is fixed at AGA 7 for both turbine and
ultrasonic meter installations.
The AGA 5 energy calculation is run once per second for all meter runs.
For diagnostic and alarming purposes specifically in ultrasonic applications,
the AGA 10 – Speed of Sound equation is run once per second. The
calculated value is compared to the measured value as retrieved from the
ultrasonic device via a communications port. If the calculated value deviates
from the measured value by a user configurable amount, an alarm is
generated.
Fwv
The water vapor factor is a direct multiplier into the flow equation that
compensates for any water vapor in the system. The number is a value close
to the one derived from the following equation:
] .
1000000
/
)
0181
.
21
)
mmc f
/
.
l b
[ ( (
1
Fwv
−
Manual: Enter the Fwv directly (usually approximately .98).
Partial Calculation: Enter the pounds of water per million cubic feet of
gas to enable the flow computer to calculate Fwv.
Full Calculation: This method assumes a fully saturated gas and uses
the current pressure and temperature of the gas to calculate what the
water content should be. The results of this calculation are then used as
the input into the Fwv equation to obtain the Fwv factor.
Differential Meters
Linear Meters
Energy
Diagnostic
Factors
