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Tanks with Negative Measurement or Level

This analysis rule includes the list of tank elements that have a negative mass or volume measurement.

While there are special circumstances where this is used, typically a negative mass or volume measurement is a gross error. A negative value can indicate the following:

  • An invalid gauge to volume calculation.
  • An invalid volume to mass calculation.
  • Missing data.
  • Invalid tank configuration.

The following table lists a sample log output for this analysis.

Sample Log

TimeSeverityElementAttributeMessage
9/1/2005 10:05...REPORTING TANK WITH NEGATIVE MEASUREMENTS OR LEVELS
9/1/2005 10:05ErrorTankALevelGauge: -10 (m)

Analysis Method​

  1. Collect a list of all tank elements in the current Case that satisfy the following criteria:
  • Status Attribute value is IS (In Service).
  1. Based on the analysis basis selection, mass or volume, check if the measurement is negative or if the level gauge Attribute is negative. If the manual adjustment value is True then use a corrected value for the comparison.
  2. Write to the log section of the case. Report the violating tank information.

Configuration Using the Wizard​

The configuration of the Tanks with a negative measurement or level gauge is a selection of the General Gross Error Analysis Rule. You open the window for configuring the test (shown in the following figure) from the General Gross Error Analysis Rule Wizard.

  1. Open the Gross Error Configuration window as described in Configuring - General Gross Error Analysis Rule.

  2. On the Tanks tab, select Tanks with negative measurements or level.

    A Tanks with negative measurements or level - Attributes window opens.Figure 383: Tanks with negative measurements or level - Attributes window

  3. Select measurement basis and Attributes according to the following table:

    Attributes

    SelectionsDescription
    Measurement BasisSelect either mass or volume basis.
    MeasuredTank inventory actual measurement. The default is 'MeasuredMass' or 'NetVolume' depending on mass or volume selection.
    CorrectedTank inventory corrected measurement. The default is 'CorrectedMass' or 'CorrectedVolume' depending on mass or volume selection.
    Level GaugeTank inventory gauge level. The default is to 'LevelGauge'.
    Manual FlagFlag to indicate if a corrected measurement was used for the tank inventory. The default is to 'ManualAdjustmentFlag'.
    StatusTank in/out of service status. The default is to 'ObjectStatus'.

  4. Click OK to finish the configuration.

    The text "CONFIGURED" displays next to the 'Tanks with negative measurements or level' selection.

  5. To run this test, see Running the General Gross Error Analysis.