Emerson Micro Motion SGM, Configuration And Use Manual

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7.4.1 Compressibility Method and process limits
Each method for calculating compressibility has specific limits for line temperature, line pressure, and other
process variables. If your process goes outside the valid range, compressibility will be reported as NaN (Not a
Number). All process variables that require compressibility will also be reported as NaN.
Table 7-1: Specific gravity and molecular weight meters: Compressibility Method and valid ranges for
process variables
Compressibility
Method
Valid range
Temperature Pressure Specific
gravity % CO2 % N2 % H2
AGA NX-19 − 40 to
+115.556 °C
1.01325 to
345.751 BarA 0.55 to 1 0–15% 0–15% 0–15%
AGA NX-19 Mod − 40 to
+115.556 °C
0 to 137.9
BarA 0.554 to 0.75 0–15% 0–15% N/A
AGA NX-19 Mod 3 0 to 30 °C 0 to 80 BarA 0.554 to
0.691 0–2.50% 0–7% 0–4%
Table 7-2: Relative density meters: Compressibility Method and valid ranges for process variables
Compressibility
Method
Valid range
Temperature Pressure Relative
density % CO2 % N2 % H2
SGERG-88 − 30 to
+100 °C
0 to 120 BarA 0.55 to 0.9 0–30%
(1)
0–50%
(1)
N/A
(1) The sum of CO2 and N2 must be less than 50%.
7.5 Configure base density calculations using ProLink III
ProLink III
Device Tools
→
Configuration
→
Process Measurement
→
Base Density
The base density parameters provide data for the base density calculations. Base density can be reported as a
process variable. For specific gravity meters and relative density meters, base density is required for line
density measurement.
Procedure
1. Choose Device Tools
→
Configuration
→
Process Measurement
→
Base Density .
2. Set Density Unit to the unit to be used for base density, and click Apply .
This unit is also used for line density.
3. Set
Base Pressure
to the pressure value to which density measurements will be corrected (the
reference pressure).
The default is 1 bar absolute. There is no upper limit. You must be using absolute pressure.
This value is also used in line density measurement. Be sure that the value is appropriate for both
process variables.
Configure process measurement using ProLink III Configuration and Use Manual
March 2021 MMI-20020954
56 Micro Motion Gas Specific Gravity Meters (SGM)