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Meters with Zero Density and Non-Zero Measurement

This analysis rule includes the mass/volume measurement elements with a zero density and a non zero measurement. For meters that are in service, a zero density is abnormal and can be the result of a lab error or a data communication error. The use of a zero density will give erroneous volume to mass conversion results. Since you can run the General Gross Error analysis as a validation step in the mass and volume balances, zero density is a potential gross error.

Any in-service meter measurement with a non zero measurement and a zero density is reported to the Case log, which you can view in the Log tab of the Case Properties window. The output contains a list of meters in violation, and a description of the violation.

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

Sample Log

TimeSeverityElementAttributeMessage
9/1/2005 10:05...REPORTING METER WITH ZERO DENSITY AND NON-ZERO MEASUREMENT - BASIS= MASS
9/1/2005 10:05ErrorMeterADensityAttached Flow = SF_FlowA; Source = SF_NodeA; Destination = SF_ProcessA

Analysis Method​

  1. Collect a list of all measurement elements in the current Case that satisfy the following criteria:
  • Meter Element Attribute representing measurement is non zero
  • Meter Element Attribute for the density is equal to zero
  • Status Attribute value is IS (In Service)
  1. Write to the log section of the case. Report the test name, the measurement basis, the difference between the measured and corrected values and the percent difference between these values (percent based on the measured value).

Configuration Using the Wizard​

The configuration of Meters with Zero Density and Non-Zero Measurement 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 Liquid/Gas Meters tab, select Meters with zero density and non-zero measurement.

    A Meters with zero density and non-zero measurement - Attributes window opens.Figure 391: Meters with zero density and non-zero measurement - Attributes window

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

    Attributes

    SelectionsDescription
    Measurement BasisSelect mass or volume measurement basis for comparison.
    MeasuredMeter actual measurement. This defaults to 'MeasuredMass' or 'MeasuredVolume' depending on mass or volume selection.
    CorrectedMeter corrected measurement. This defaults to 'CorrectedMass' or 'CorrectedVolume' depending on mass or volume selection.
    Manual FlagFlag to indicate if a corrected measurement was used for the meter. This defaults to 'ManualAdjustmentFlag',
    DensitySelect density Attribute to test. The default is 'Density'.
    StatusMeter in/out of service status. This defaults to 'ObjectStatus'.

  4. Click OK to finish the configuration.

    The text "CONFIGURED" displays next to the 'Meters with zero density and non-zero measurement' selection.

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