Siemens SITRANS FUH1010, Product Instruction Manual, Page: 84 / 264

Functions
7
7.1 Setting Liquid Parameters
Introduction
The flow meter 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 monitored
by the flow meter. 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
(15.6ºC/60ºF) 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.
Calculating the LiquIdent Slope Factor
1. 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 Data menu in [Liquid Data]) at Tmax and the sonic velocity at Tmin (in-meters-
per-second).
2. Use the following formula to calculate the LiquIdent Slope Factors with the Liquid Class:
/LTXLG6ORSH)DFWRU 9
V
#
7
PLQ
9
V
#
7
PD[
7
PD[
7
PLQ
Note
If the Celsius scale is used for Tmax and Tmin, multiply the result by 0.56 to obtain the
liquid’s LiquIdent Slope Factor.
3. Calculate the average of all the LiquIdent Slope Factors with the Liquid Class.
FUH1010 IP65 NEMA 4X Precision Volume
Operating Instructions, 01/2013, A5E32122003-AA
83