Honeywell SmartLine Multivariable SMV800 Series User Manual page 287

B.2 Standard Flow Equation
The Standard Flow Equation (Kuser Model) allows automatic calculation of the Kuser value that is
used to configure PV4 flow variable for SMV 3000. The Kuser value is a scaling factor, based on the
dynamics of your process, which is used to adjust the flow rate to the desired process parameters,
such as
-
dimensional units
-
density
-
pressure
-
temperature
The standard flow model uses an empirical method to configure PV4 flow variable for the following
primary elements:
-
orifice plates
-
Venturis
-
nozzles
-
averaging pitot tubes
-
and other flow elements with outputs proportional to
The standard flow model can be used to calculate PV4 for volumetric and mass flow rates for gas,
liquid, and steam at standard conditions. A flow equation for steam mass is also available which
compensates for density based on the ASME steam tables
NOTE: Use the dynamic flow compensation model for increased flow measurement accuracy. See
Subsection B3.
Standard Flow Equation Configuration Examples
The following pages contain two examples for configuring the SMV PV4 output using the Flow
Compensation Wizard in the SCT 3000 configuration program. The configuration examples show
how to navigate through the wizard program and enter values to configure the SMV PV4 flow
variable for a given flow application. Examples for the following applications are presented:
· Air through a Venturi meter
· Superheated Steam
The standard (Kuser) model wizard in the SCT 3000 is started from the Equation Model page of the
Flow Compensation Wizard.
Example: Air Through a Venturi
An engineer has specified a SMV 3000 Smart Multivariable Transmitter to compensate for air density
changes and to calculate the standard volumetric flowrate of air through a Venturi meter. The
engineer has sized the Venturi meter to produce a differential pressure of 49 inches H2O at 630 CFM
at standard conditions. The flowing pressure is 129.7 psia, flowing temperature is 100 degrees F, and
the standard (base) density is 0.0764 lbs/ft3.
The steps in Table 59 show how to configure the SMV to calculate the PV4 flow variable for this
application.
Revision 6.0
SMV800 Transmitter User's Manual
Page 275