C.2 Standard Flow Equation

Standard Flow

Compensation

(Kuser Model)

Standard Flow

Equation

Configuration

Examples

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 DP .

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 C.3.

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.

Continued on next page

176

SMV 3000 Transmitter User’s Manual

1/99

Page 188
Image 188
Honeywell SMV 3000 user manual Standard Flow Equation