Emerson Process Management ControlWave EFM 3808 - Manual (Page 228)

F-28 / Appendix F CI-ControlWave EFM
(1992) equation by toggling the push button labeled Click Here to select AGA3I
(1992).
F.6.3.1.2 1985 AGA3 Equation Configuration
The user must configure the inputs to the equation.
Pressure Tap – The user must select Pressure Tap type and location. The type is defined
Flange or Tap and the location is defined as Upstream or Downstream. Pressure Tap is
selected as follows:
1 DOWNSTREAM FLANGE
2 UPSTRERAM FLANGE
3 DOWNSTREAM TAPS
4 UPSTREAM TAPS
Figure F-18A - (1985 AGA3) Orifice Flow Equation Setup Web Page
Low Flow Cut Off - When the differential pressure drops below the low flow cut off value,
the flow rate will be set to zero. Default units are “inches of water.”
Orifice Diameter - Orifice diameter is entered here. Default units are “inches.”
Pipe Diameter - Diameter of the pipe is entered here. Default units are “inches.”
Orifice Constant - K (AGA3 1985) - Orifice constant is entered here.
Adjust Press. - Users enter Average Barometric Pressure here.
Diff. Pressure - Actual value of Differential Pressure (Inches H
2
O) are displayed here.
Static Pressure - Actual value of Static Pressure (psig) are displayed here.
Temperature - Actual value of Temperature (Deg. F) are displayed here.
Specific Gravity - Specific Gravity of the gas being measured is displayed here.