Gas & Liquid Flow Computer for CompactLogix

The MVI Liquid & Gas Flow Computer Module is a CompactLogix backplane compatible module that allows CompactLogix processors to easily support flow applications with 8 meter runs performing measurement of hydrocarbon gases or liquids using AGA 3, 7, 8 and API 2540 measurement standards.

Features and Benefits

The MVI69-AFC is an in-rack Liquid & Gas Flow Computer Module for the CompactLogix platform. The MVI69-AFC Flow computer module supports 8 meter channels for the measurement of hydrocarbon gases and liquids using currently accepted industry measurement standards.

The module calculates flow rates, accumulated volumes, accumulated mass and accumulated energy (heating value). The calculation results are transferred back to the Processor memory for use in the application ladder program or for transfer back to a SCADA host.

The MVI69-AFC Flow Computer package contains built-in support for system configuration, monitoring, documenting, and overall management such as:

  • System configuration via a user-friendly MS Windows-based AFC Manager
  • Ability to manage multiple site installations as separate projects saved on a PC
  • Option to access archives online and print/save to a spreadsheet compatible file
  • Option to generate, print, and save configuration and on-line management reports
  • Ability to monitor the meter runs on-line
  • Password protection for preventing unauthorized configuration changes


The MVI69-AFC module is the ideal solution for the many applications where hydrocarbon flow and SCADA communication must be added to the CompactLogix platform. Applications using the MVI69-AFC module can be found mainly in the oil and gas industrial sectors.

Functional Specifications

The AFC module operates as a powerful flow computer module, augmenting the operation of the CompactLogix processor by providing a dedicated and accurate set of flow calculations; the results of which are easily available to process monitoring and control applications developed in the CompactLogix.

The module is highly-configurable, allowing each of the 8 meter runs to be individually setup to meet the specific requirement of an application. Some of the configurable parameters include:

Configurable options

  • Gas analysis concentrations for any or all 21 components
  • Physical data for all meter runs including, orifice and pipe diameters, selection of type of taps and tap location etc.
  • Reference pressure, temperature and local atmospheric conditions
  • Default process and operating parameters like DP threshold for flow cutoff etc.
  • Metric or imperial units
  • User selectable units for totalizers and flow rates on a per channel basis
  • Resettable and/or non-resettable totalizers for every meter channel
  • Process I/O: analog inputs (pressure, temperature, diff pressure) from analog modules and pulse inputs from pulse/frequency input modules in CompactLogix I/O rack
  • Number of meter channels: 8 differential (AGA3) or linear (AGA7) Gas; MPMS 12.2 Liquid
    • Calculation methods
    • AGA3-199
    • AGA 7
    • AGA8-1992 (detailed characterization method)
    • API MPMS Ch12.2 API 2540
    • Meter scan time under 1 second for all 16 channels
  • Product measurement: hydrocarbon gases and liquids
  • Data archiving: For each meter run, hourly for two days (48 records) and daily for one month (35 records) under default configuration, with optional extended archives up to 1440 hourly (60 days) and 1440 daily. Archive size and contents are fully configurable. All archived data is available in the onboard Modbus memory.
  • Each record consists of nearly 20 process and other variables. All archived data is available in the onboard Modbus memory map (archive size and contents are fully-configurable)


  • Event log report for all security sensitive configuration data (for example, orifice diameter) are date and time stamped and mapped to the local Modbus memory map. This data can be imported into any spreadsheet program and saved to disk or printed as hard copy.
    • Hourly and daily archive reports mapped to local Modbus memory. This data can be imported into any spreadsheet program and saved to disk or printed as hard copy.
  • System configuration which can be downloaded or uploaded from the module, can also be printed for hard reference or archiving.

Modbus interface

  • The two Modbus slave ports allow the unit to be used as a SCADA interface and to broaden access to the AFC module's data table.
  • Either port may be configured for RTU or ASCII Modbus mode.
  • Both Modbus slave ports provide access to all configuration and measurement data mapped to the Modbus table.
  • Modbus table may be re-mapped for user assigned contiguous register polling from a SCADA master (up to 20,000 registers.)

Hardware Specifications


Standard 1769 Single-slot module

Current Load

800 mA max@ 5 VDC (Serial)
Power supply distance rating of 2 (L43 and L45 installations on first 2 slots of 1769 bus)

Operating Temp.

0 to 60 Deg C

32 to 140 Deg F

Storage Temp.

-40 to 85 Deg C

-40 to 185 Deg F

Relative Humidity

5 - 95% (w/o condensation)

LED Indicators

Power and Module Status

Application Status

Serial Port Activity

Serial Activity and Error Status

CFG Port

RJ45 (DB-9M w/ supplied cable)

RS-232 only

No hardware handshaking

App Ports (P1, P2)

RJ45 (DB-9M w/supplied cable)

RS-232 handshaking configurable

500V Optical isolation from backplane

Shipped with Unit

RJ45 to DB-9M cables for each port

6-foot RS-232 configuration Cable


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