Rosemount 5600 Series, Справочное руководство

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Reference Manual
00809-0100-4024, Rev BA
September 2005
Rosemount 5600 Series
4-10
VOLUME CALCULATION
The Volume Calculation is performed by using one of two methods:
predefined tank shape or strapping table. The strapping table is an optional
function. If this function is required, please contact your local Rosemount
representative.
To configure the 5600 transmitter for volume calculations you have to choose
a Volume Calculation method.
Select one of the volume calculation methods. Choose one of the ideal tank
shape options if approximation of your tank with an ideal tank shape provides
sufficient accuracy. The strapping table option can be used for an arbitrary
tank shape. You can enter levels and corresponding volumes to obtain a close
match between the actual and the calculated volume. This option should be
used in cases where the tank shape deviates significantly from an ideal
sphere or cylinder, or when you require high accuracy.
NOTE
The transmitter is delivered with a code that enables the ordered software
options including strapping table volume calculation. If you wish to change the
set of available options, contact your local Rosemount representative.
Ideal Tank
Use this option if approximation of your tank with an ideal tank shape
(assuming no dished ends) provides sufficient accuracy. Enter the following
parameters:
• Tank Diameter (and the length if it is a horizontal tank).
• Volume Offset: Use this parameter if you do not want zero volume and
zero level to match (for example if you want to include volume below
the zero level).
Strapping Table
• Enter levels and corresponding volumes starting at the bottom of the
tank. These figures can typically be obtained from tank drawings or
from certificate from the tank manufacturer. If the level//volume table is
based on a reference point that is different from your reference point,
you can use Level Offset and Volume Offset. The Volume Offset is
added to every value in the corresponding column.
• Select which interpolation method to use for calculating volumes
between the strapping points. Normally, linear interpolation is the
preferred method. For spherical tanks, quadratic interpolation may
result in a smaller error. By using linear interpolation and a sufficient
number of values in the strapping table, the interpolation error can
normally be reduced to a minimum.