Reference K-Factor - Emerson Rosemount 8800D Series Reference Manual

Configuration
May 2016
Fixed Process Temperature
FastKeys
Needed for the electronics to compensate for thermal expansion of the flowmeter as the
process temperature differs from the reference temperature. Process temperature is the
temperature of the liquid or gas in the line during flowmeter operation.
May also be used as a back-up temperature value in the event of a temperature sensor
failure if the MTA option is installed.
Fixed Process Density
FastKeys
A Fixed Process Density must be accurately configured if mass flow or corrected volume
flow measurements are used. In mass flow it is used to convert volume flow to mass flow. In
corrected volume flow it is used with the base process density to derive a density ratio
which in turn is used to convert volume flow to corrected volume flow. In temperature
compensated fluids the fixed process density is still required as it is used to convert volume
flow sensor limits to sensor limits for temperature compensated fluids.
Note
If mass or corrected volume units are chosen, you must enter the density of your process
fluid into the software. Be careful to enter the correct density. The mass flow rate and
density ratio are calculated using this user-entered density, and unless the transmitter is in
TComp Sat Steam or TComp Liquids mode where changes in density are automatically
being compensated for, any error in this number will cause error in the measurement.
Base Process Density
FastKeys
The density of the fluid at base conditions. This density is used in corrected volume flow
measurement. It is not required for volume flow, mass flow, or velocity flow. The Base
Process Density is used with the Process Density to calculate the Density Ratio. In
temperature compensated fluids, the Process Density is calculated by the transmitter. In
non-temperature compensated fluids the Fixed Process Density is used to calculate a fixed
Density Ratio. Density Ratio is used to convert actual volumetric flow to standard
volumetric flow rates based on the following equation:
DensityRatio
2.2.4

Reference K-factor

FastKeys
A factory calibration number relating the flow through the meter to the shedding frequency
measured by the electronics. Every 8800 meter manufactured by Emerson is run through a
water calibration to determine this value.
12
2, 2, 1, 1, 4
2, 2, 3, 1
2, 2, 3, 2, 1
density at actual (flowing) conditions
= ------------------------------------------------------------------------------------------------------- -
density at s tan dard (base)
2, 2, 1, 2, 1
Reference Manual
00809-0100-4004, Rev DC
conditions
Configuration