Siemens SITRANS FUH1010PVX, Operating Instructions Manual, Page: 81 / 226

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1010BXFM-3
Section 2
Setting The LiquIdent™ Slope
The Interface Detector measures and reports the flowing liquid’s sonic velocity (Vs) and its
temperature (T). These components create the liquid’s “Vs/T” signature. This signature is a
fundamental component of the LiquIdent™ routine that identifies positively any liquid moni-
tored by the 1010BX system. Since a temperature change will affect the sonic velocity of the
liquid, a method to balance the measured sonic velocity to a fixed reference temperature (60ºF/
15.6ºC) is provided. The LiquIdent™ Slope Factor must be configured to represent the linear
change in the liquid’s sonic velocity per degree Fahrenheit. The LiquIdent™ routine uses this
slope factor to maintain an accurate liquid identification as the liquid temperature varies.
NOTE: The LiquIdent™ Slope Factor for all liquids within a liquid class should be
essentially identical, 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 PC numeric keys or Magnetic Wand to enter desired LiquIdent™ Slope Factor.
To enter the LiquIdent™ Slope Factor press .
Setting The Pressure Slope
The Interface Detector 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 measured sonic velocity to a fixed reference temperature (60ºF/15.6ºC
default) is provided. This pressure slope factor helps maintain an accurate liquid identifica-
tion as the LiquIdent™ factor and liquid temperature vary.
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