Configure Gas Compressibility Measurement Using Prolink Iii - Emerson Micro Motion SGM Series Configuration And Use Manual

Configure process measurement using ProLink III
7.4 Configure gas compressibility measurement
using ProLink III
ProLink III
Overview
Gas compressibility measurement is required for the following process variables: line
density, calorific value, Wobbe index, and energy flow. Gas compressibility measurement
can also be used to calculate compressibility as an independent process variable.
Prerequisites
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Procedure
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Device Tools > Configuration > Process Measurement > Compressibility
You must know whether you will measure line compressibility and base
compressibility or you will use fixed values.
If you will use fixed values, you must know the line compressibility and base
compressibility values for your application.
If you will measure compressibility, you must be able to supply gas composition data
to the meter, for the following constituents:
- Carbon dioxide (CO2)
- Nitrogen (N2)
- Hydrogen (H2) (required only if you plan to measure compressibility according
to SGERG 88)
Gas composition must be measured in % by volume.
If you plan to poll an external device for % CO2, % N2, or % H2, ensure that the meter
has the required polling slots available. The meter provides four polling slots, and
they may be already in use. You may need to use a fixed value or digital
communications for some external values. To check the current polling
configuration, choose Device Tools > Configuration > Polled Variables.
Choose Device Tools > Configuration > Process Measurement > Compressibility.
Set Compressibility Calculations as desired, and click Apply.
Option Description
Disabled The meter will not calculate compressibility. You must enter fixed values for line
compressibility and base compressibility.
Enabled The meter will calculate line compressibility and base compressibility. You must
provide gas composition data.
If you set Compressibility Calculations to Disabled:
a. Set Line Compressibility to the compressibility of your sample gas at line
temperature and line pressure.
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Micro Motion Gas Specific Gravity Meters (SGM)