Gas & Liquid Flow Computer for PLC

MVI71-AFC

The MVI71 Liquid & Gas Flow Computer Module is a PLC backplane compatible module that allows PLC 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 MVI71-AFC is an in-rack Liquid & Gas Flow Computer Module for the PLC platform. The MVI71-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.

General Specifications

• Single Slot - 1771 backplane compatible
• The module is recognized as an Input/Output module and has access to processor memory for data transfer between processor and module
• Ladder Logic is used for data transfer between module and processor.
• Configuration data obtained through user-defined ladder. Sample ladder file included

Applications

The MVI71-AFC module is the ideal solution for the many applications where hydrocarbon flow and SCADA communication must be added to the PLC platform. Applications using the MVI71-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 PLC 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 PLC.

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 such as 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 PLC I/O rack
• Number of meter channels: 8 differential (AGA3) or linear (AGA7) Gas; MPMS 12.2 Liquid
• Calculation methods: AGA3-1992, AGA 7, AGA8-1992 (detailed characterization method), API MPMS Ch12.2 API 2540
• Meter scan time under 1 second for all 8 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.
• 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.

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.
• Modbus table may be re-mapped for user assigned contiguous register polling from a SCADA master (up to 20,000 registers).
• Port 3 can be configured as a Modbus Master port to poll data from a remote chromatograph device.

Hardware Specifications

Ordering Information

Distributors:
Place your order by email to orders@prosoft-technology.com:, fax to +1 661-716-5101.

Sales and Support:

AFC Version 2.05 Update Notice

If your module measures liquids, please read this notice before upgrading from version 2.04 (or earlier) to 2.05 (or later).

For compliance with new measurement standards, the AFC version 2.05 has introduced several new liquid product groups. In particular, the two non-refined liquid product groups of version 2.04, which covered the entire density range of crudes and NGLs, have each been split into two separate product groups, one for the higher density range of crudes and the other for the lower density range of NGLs. If your module has meter channels configured for either "Crude, NGL" or "Oil-water emulsion", you should decide before upgrading the firmware the new product group (light or heavy) to which each such channel should be assigned. This assignment will be performed during the upgrade process and will preserve all other configuration and historical records including accumulator values and archives, in contrast to changing a product group after the upgrade which resets the meter configuration and erases all historical records. Meter channels configured for "Gas" or "Refined products" are not affected.

AFC Manager exhibits the same behavior when converting a project between versions 2.04 (or earlier) and 2.05 (or later).

The criterion for assigning the new product group depends on the density units and the Default Reference Density, as detailed in the following tables:

Density Units = kg/m3

Density Units = Rd/60

Due to roundoff error of numeric conversions, a Relative Density very close to the cutoff value of 0.6100 may cause the module to assign the new product group opposite to the one that was intended. Before upgrading, change the Default Reference Density to a number significantly different from 0.6100, such as 0.6110 (to target Crude) or 0.6090 (to target NGLs). You may change it back to the correct value after the upgrade

Density Units = API Gravity