COMPENSATED FLOW
COMPENSATED FLOW
(OP)
HELLO,
I am using a Siemens S7 plc to read the flow rate using a Orifice type of transmitter.The client also provides the pressure and temperature of the material in the line as analog values to the PLC.I am required to display a temperature and pressure compensated flow on the HMI.How is this done.Does anyone have a standard formula for the same or is there a standard Function block.
Thanks,
Samuels
I am using a Siemens S7 plc to read the flow rate using a Orifice type of transmitter.The client also provides the pressure and temperature of the material in the line as analog values to the PLC.I am required to display a temperature and pressure compensated flow on the HMI.How is this done.Does anyone have a standard formula for the same or is there a standard Function block.
Thanks,
Samuels





RE: COMPENSATED FLOW
Boyles and Charles Law
((P1*V1)/T1)=((P2*V2)/T2)
P= pressure
T= Temperature
V= Volume
Set1 = Known conditions using your orifice plate coefficients
Set2 = Actual conditions
I don’t have enough time but to continue right now. I should have a more complete formula somewhere, if some one else does not post it I will Later.
RE: COMPENSATED FLOW
Q = Flow
P = Pressure (PSIA)
T = Temperature (Rankin)
Set1 = Known Flow (calculated from orifice data)
Set2 = Compensated Temp Flow (Substitute new temp)
Set3 = Compensated Pressure Flow (Substitute new press)
Q2 = SQRT(T1/T2) * Q1
Q3 = SQRT(P3/P1) * Q2
Actual Flow = Q3
PSIA = PSIG – 14.73
DegR = DegF + 460