Siemens SITRANS FUH1010PVDX, Operating Instructions Manual, Page: 119 / 308

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CQO:1010PVXFM-3 Section 5
NOTE: The LiquIdent Slope Factor for all liquids within a liquid class should be essentially iden-
tical, even though their individual sonic velocities may be very different.
This menu cell allows the LiquIdent Slope Factor to be edited for optimal operation. The LiquIdent Slope
Factor default is 2.300. This default factor applies to hydrocarbon liquids at the reference temperature of
60ºF/15.6ºC (default).
To calculate a liquid’s LiquIdent Slope Factor:
Establish the maximum (Tmax) and minimum (Tmin) operating temperatures for all liquids within the
Liquid Class. For each liquid, note the measured sonic velocity (located in the Diagnostic Menu) at
Tmax and the sonic velocity at Tmin (in-meters-per-second).
Use the following formula to calculate the LiquIdent Slope Factors with the Liquid Class:
LiquIdent Slope Factor = (Vs @Tmin) - (Vs @Tmax)
(Tmin - Tmax)
NOTE: If the Centigrade scale is used for Tmax and Tmin, multiply the result by 0.56 to obtain
the liquid’s LiquIdent Slope Factor.
Calculate the average of all the LiquIdent Slope Factors with the Liquid Class.
To enter the LiquIdent Slope Factor:
From the [Liquid Table] menu cell, press to scroll down to LiquIdent Slope.
Press to enable numeric entry.
Use the keypad numeric keys to enter desired LiquIdent Slope Factor.
To enter the LiquIdent Slope Factor press .
Setting The Pressure Slope
The FUH1010PVX measures and reports the flowing liquid’s sonic velocity (Vs) and its related pressure
(P). Since a pressure change will affect the sonic velocity of the liquid, a method to balance the mea-
sured sonic velocity to a fixed reference temperature (60ºF/15.6ºC default) is provided. The Pressure
Slope Factor default is 0.030 (m/s per PSI). This pressure slope factor helps maintain an accurate liquid
identification as the LiquIdent factor and liquid temperature vary.
The FUH1010PVX has the ability to accept a 4-20 mA input for pressure. If used, the FUH1010PVX will
process pressure data based on the analog input. This is recommended for pipelines that have wide
pressure variances.
To calculate a liquid’s Pressure Slope Factor:
Establish the maximum (Pmax) and minimum (Pmin) pressures for all liquids within the Liquid Class.
For each liquid, note the measured sonic velocity at Pmax and the sonic velocity at Pmin (in-meters-
per-second).
Use the following formula to calculate the Pressure Slope Factors with the Liquid Class:
Pressure Slope Factor = (Vs @Pmin) - (Vs @Pmax)
(Pmin - Pmax)
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