Contrec 515 – GN01

Frequency Input Natural Gas Flow Computer

The 515 GN01 application measures the volume, mass and gross heat content of a natural gas. The instrument uses a frequency volume flow input and analog temperature and pressure sensor inputs.

The instrument is compatible with a wide range of flowmeter frequency outputs. Millivolt signals, reed switches, Namur proximity switches or pulse trains can be selected via its smart front-panel programming.

The AGA-8 Detail Characterization Method is used to obtain accurate values of density and compressibility factors for the flow calculations.


The gas density and compressibility factor calculations are based on the AGA-8 equations. The calculations are valid for the region:

-130°C < t < 400°C P < 280MPa -200°F < t < 760°F P < 40000psia FORMULAS Mflow = volumeflow•ρflow corrected flow = Mflow/ρ ref Heat flow = Mflow•Hm Where: Mflow = mass flow ρflow = density at flow conditions ρ ref= density at reference conditions Hm= mass gross heating value