Rosemount 3107, Reference Manual

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43
Reference Manual
00809-0200-4840, Rev BA
Section 4: Configuration
December 2014
Section 4: Configuration
5. Follow the on-screen instructions to select and save the new setting. (Press the Enter
( ) key if prompted to change the mode to “off-line”).
6. Select “ Quit ” to exit to the previous menu.
4.3.12 Contents (volume) measurement
There are 5 shape options available to select, including:

Tank shape/NLP (P011) = “Linear” (see page 43 )

Tank shape/NLP (P011) = “Special Plot” (see page 43 )

Tank Shape/NLP (P011) = “Horizontal Cyl Flat” (see page 46 )

Tank Shape/NLP (P011) = “Spherical” (see page 46 )

Tank Shape/NLP (P011) = “Horizontal Cyl Dome” (see page 47 )
Tank shape/NLP (P011) = “Linear”
This default setting is for level or volume (content) measurements involving a tank with a
constant cross-section. When “
Linear ” is selected, the level or volume is the liquid height above
the zero level multiplied by a scaling factor. If volume is not required, the Scale Factor parameter
( page 52 ) is set to 1.0 unless other measurement units for the output PV are required.
The volume of the contents is calculated by entering the volume-per-meter of height into the
Scale Factor parameter ( page 52 ). If the liquid level is being measured in feet or inches, enter
the volume-per-feet or volume-per-inch respectively.
Tank shape/NLP (P011) = “Special Plot”
When selecting “ Special Plot ”, parameters Profile Point 1 to 10 ( page 55 ) can be edited to plot
the unique profile of an irregular shaped tank or open channel (see Figure 4-2 on page 44 ).
To derive the 10 profile points, it is necessary to have tabulated or graphical data to relate the
process value (PV) to the live liquid height.
Figure 4-3 on page 45 shows an example graph of PV
versus Liquid Height. In the example, 60% of the maximum height on the X-axis relates to a
percentage of the maximum PV on the Y-axis. The related percentage, say 55%, is entered into
parameter
Profile Point 6 .
The transmitter will interpolate linearly between the plotted points to give an accurate curve fit,
which will determine the output PV from the live level (height) measurement.
Each live level measurement is converted into a percentage (0 to 100%), which is proportional to
the maximum height. In graph terms, the converted percentage corresponds to an X ordinate
on the X-axis. Using this X ordinate, the Y ordinate is then calculated to get a percentage
proportional to the maximum PV. This percentage is multiplied by the maximum height to get
the output process value (PV).