Emerson Micro Motion SGM Series User Manual

2.4 Equations used to calculate specific gravity,
molecular weight, and relative density
Core process variable = Specific gravity
The following equations are used when the core process variable is specific gravity.
Specific gravity Equation 2-1:
SG = K0 + K1 ×  + K2 × 
2
SG
Specific gravity of process gas
K0, K1, K2
Calibration factors from the on-site calibration. If a two-point calibration was
performed, K1 is set to 0.
τ
Sensor time period (microseconds)
Molecular weight calculated from specific gravity Equation 2-2:
MW
Gas
= SG
Gas
× MW
Air
MW
Gas
Molecular weight of process gas (g/mol)
SG
Specific gravity of process gas
MW
Air
Molecular weight of air (user-specified; default = 28.96469 g/mol)
Core process variable = Molecular weight
The following equations are used when the core process variable is molecular weight.
Molecular weight Equation 2-3:
MW = K0 + K1 ×  + K2 × 
2
MW
Molecular weight of process gas
K0, K1, K2
Calibration factors from the on-site calibration. If a two-point calibration was
performed, K1 is set to 0.
τ
Sensor time period (microseconds)
Orientation and planning
Configuration and Use Manual 13

Emerson Micro Motion SGM Series Specifications

General

Brand	Emerson
Model	Micro Motion SGM Series
Category	Measuring Instruments
Language	English