Kistler-Morse KM SVS2000 - Manual (Page 41)

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97-1129-01 Rev. D
4. Use the numeric or Arrow Keys to input a value that represents the estimated quantity of material in the
vessel. Press the Enter Key to save the value in memory. The display acknowledges the entry and
returns to:
LO SPAn CAL
5. Press the up Arrow key to proceed to the next menu. The display shows:
HI SPAn CAL
6. Add a known quantity of material, representing at least 25% of the vessel’s total capacity, to the vessel.
7. Press the enter key to access the Hi Span Cal menu. The display looks like this:
> ------ lbs
(Units are consistent with Disp Units.)
8. Use the numeric or Arrow Keys to input a value equal to the sum of the known quantity (Step 6) and the
estimated quantity (Step 4). Press the Enter Key to save the value in memory. The display acknowledges
the entry and returns to:
HI SPAn CAL
9. Press the Gross or net Key to return to Run Mode.
note: Shifting from the dashed to the solid line in Figure 8 is accomplished by entering a Display value
Correction when the vessel contains a known quantity of material (usually none) at a later date. This procedure is
described in refining the Calibration with the Display value Correction in this section.
calIBraTIon By SuBTracTIng a KnoWn quanTITy oF MaTerIal
This calibration method does not require the vessel to be empty. This method of calibration is appropriate when
it is easier to remove material from the vessel than to add it. The principle behind the calibration follows. A
weight estimated to be the quantity of material in the vessel is entered as the Hi Span weight [point (2) in Figure
8]. A known quantity of material, representing at least 25% of the vessel’s total capacity, is removed from the
vessel.
The estimated Hi Span weight minus the known quantity that is removed is entered as the Lo Span weight [point
(1) in Figure 8]. The SvS2000 saves in memory the Lo Span and Hi Span weights as well as the digital counts
associated with each weight. These values define the dashed straight line and the calculated Zero Counts shown
in Figure 8. The slope of the line is called the Scale Factor, which is calculated internally. The slope of the line is
reasonably accurate, because it is calculated based on the known difference between the Lo Span and Hi Span
weights and counts.
However, if the estimated Hi Span value is incorrect, the actual ‘location’ of the line is incorrect, resulting in
errors in vessel monitoring. The greater the error in the estimated Hi Span, the greater the resulting error. The
‘location’ of the line can be adjusted to the solid line by entering a Display value Correction [point (3) in Figure 8]
(see refining the Calibration with the Display value Correction in this section). Similarly to the other calibration
methods, the greater the known quantity of material movedduring the calibration procedure, the greater the
accuracy. Removing 50% of the total capacity results in greater accuracy than removing 25% of the total