ProSoft Technology MVI56-AFC - Manual (Page 34)

Meter Channel Functionality MVI56-AFC ♦ ControlLogix Platform
User Manual Liquid and Gas Flow Computer
Page 34 of 316 ProSoft Technology, Inc.
February 25, 2011
3.3 Differential (Orifice) Meter Overview
The static pressure of the gas stream can be measured either upstream of the
meter (before the differential pressure drop), or downstream of the meter (after
the pressure drop). Both AGA3 and AGA8 require the upstream static pressure
for their calculations, where:
upstream pressure = downstream pressure + differential pressure
If the pressure is measured from a downstream tap (typical), the Downstream
Static Pressure option should be set through the AFC Manager.
The module also supports the V-Cone device. You can configure V-Cone meters
and downstream selections in AFC Manager, on the Meter Configuration /
Calculation Options dialog box.
3.3.1 Primary Input = Differential Pressure
The primary input parameter configures the value used as source for the
accumulator calculation. If the parameter is set to Differential Pressure, the
module uses the differential pressure value transferred through the backplane for
accumulator calculation.
3.3.2 Primary Input = Flow Rate
You can configure the primary input parameter as flow rate in order to use this
value for the accumulator calculation.
Note: The flow rate can be converted to a different unit.
The AFC Manager software supports the following parameters:

Orifice Plate and Meter Tube Measured Diameter

Orifice Plate and Meter Tube Measurement Temperature

Orifice Plate and Meter Tube, Coefficient of Thermal Expansion

DP Flow Threshold (kPa)

DP Alarm Threshold (kPa)