Siemens Moore 353 User Manual page 42

Function Blocks
G
= real gas relative density (specific gravity)
r
Z
= compressibility at standard conditions
s
Z
= compressibility at flowing conditions at upstream tap -
f
Z
= compressibility at base conditions
b
G
The specific gravity factor (
(Hold) function blocks, computed, and then downloaded from a host device, or calculated in the controller using the
AG8 (AGA 8 Compressibility Factors of Natural Gas) function block.
The following are analog outputs of the AGA 3 function block:
Q
= volume flow rate at base conditions (SCFH - Standard Cubic Feet per Hour)
b
C'
= composite orifice flow factor [SCFH/
3-12
) and the compressibility factors (
r
√
(psia)(in H2O)]
P
h
f
AGA 3
G Z
r, f,s,b
Application Diagram
Z
f1
Z , Z , Z
) can be entered manually using HLD
s f b
T
f
w
Q
b
UM353-1
March 2003