Emerson Rosemount 5408, Справочное руководство

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C.3.3 Volume
Select if the volume measurement should be calculated from the configured tank
dimensions or a strapping table.
Strapping tables can be used for irregularly shaped tanks, to eliminate errors due to
bulging when product is added to a tank, or if a pre-defined tank type does not provide
sufficient accuracy.
Strapping table
Strapping table requires entering level-volume pairs in a table (maximum 50 points). Use
most of the strapping points in regions where the tank shape is non-linear. Starting at the
bottom of the tank, for each new point, enter the total volume up to the specified level
value.
Volume offset
Use this parameter to add a volume to each calculated volume value, for example a sump
volume below the Zero Level in the tank.
C.3.4 Scaled variable
The scaled variable can be used to convert a transmitter variable into an alternative
measurement, such as open channel flow, mass, or calibrated level (e.g. 5 point
verification). This variable is available only for transmitters ordered with Smart Diagnostics
Suite (option code DA1).
The scaled variable is defined by creating a table of transmitter variables and
corresponding output variables. A maximum of 50 points can be specified. Between the
points linearly interpolated values are calculated.
Figure C-15: Scaled Variable Examples
Input Variable: Output Variable:
Level Flow
Volume Mass
Level Calibrated Level
As an example, consider a product with a density of 900 kg/m
3
. In this case, the volume to
mass conversion is given by the following table:
Table C-2: Example of Scaled Variable Table
Number Input value (volume) Output value (mass)
1 0 m
3
0 ton
2 100 m
3
90 ton
Reference Manual Configuration parameters
00809-0100-4408 February 2020
Rosemount 5408 and 5408:SIS Level Transmitters 263