Emerson Rosemount 3095, Справочное руководство, Страница: 72 / 130

Reference Manual
00809-0100-4716, Rev JA
May 2008
Rosemount 3095 MultiVariable
3-42
HART
Primary Element Selection
The Primary Element Selection Screen lets you configure the primary element
used with the 3095. The following steps apply to all fluid types (gas, fluid,
natural gas, steam).
1. Select the general type of primary used under the “Category “header.
2. Select the specific type of primary used under the “Specific Primary
Element” header.
NOTE
If complying with AGA3 Natural Gas, the primary element should be an orifice
plate with AGA flange taps.
If a calibrated primary is selected, you will be prompted to enter values to a
table of Flow Coefficients vs. Reynolds Numbers at the next screen.
If a primary is selected with Constant Cd, you will be prompted to enter a
single value for the Discharge Coefficient at the next screen.
3. Enter the orifice diameter, sensor size, or beta ratio. This parameter
will be different depending on the type of primary selected during the
previous two steps.
NOTE
To be in compliance with appropriate national or international standards, beta
ratios and differential producer diameters should be within the limits as listed
in the standards. The EA software will alert the operator if a primary element
value exceeds these limits. However, the EA software will not stop the
operator from proceeding with a flow configuration because of this type of
exception.
4. Enter the primary element material (see Table 3-4 and Figure 3-34 on
page 3-43).
5. Enter the meter tube diameter (pipe ID) and units at reference
temperature for the measured dimension.
6. Enter the meter tube material.
7. Click “Next”.