ProSoft Technology PTQ-AFC - Manual (Page 71)

PTQ-AFC ♦ Modicon Quantum Platform Quick Start
Liquid and Gas Flow Computer for Hydrocarbon Products User Manual
ProSoft Technology, Inc. Page 71 of 259
June 23, 2011
6.7.2 Linear (Pulse) Meter Overview
The module typically receives the pulse count and pulse frequency values from a
high-speed counter module. The module uses these values to perform
calculations.
You can configure the primary input to be used for volume calculation. You can
configure it as Pulse Count or Pulse Frequency.
Primary Input = Pulse Count
If you select Pulse Count as the primary input, the module uses the pulse count
value transferred through the backplane as the primary input for volume
calculation. In this case, the pulse frequency will be used for flow rate calculation
only.
Primary Input = Pulse Frequency
If you select Pulse Frequency as the primary input, the module uses the pulse
frequency value transferred through the backplane as the primary input for both
flow accumulation and flow rate calculation. The pulse count value is ignored by
the module.
6.7.3 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.