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Meters Density Comparison Between Cases

This analysis rule indicates the in-service mass/volume measurement elements with a change of density value between Cases that is greater than the configured delta limit (density). The limit is in percent of value and in engineering units. A limit of zero means that the limit has not been configured. The limit must be greater then zero for the limit to be used.

Any in-service meter measurement with a density value change greater than the configured limit 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 DENSITY COMPARISON BETWEEN CASES
9/1/2005 10:05WarningMeterADensityCurrent Case: 125 (SG) , Previous Case:1 (SG), Diff: 124, %Diff: 99.2

Analysis Method​

  1. Collect a list of all measurement elements in the current Case that satisfy the following criteria:
  • Status Attribute value is IS (In Service).
  1. For each meter, calculate the difference between the density and the value from the previous case.
  2. Write to the log section of the case. Report the test name, the measurement basis, the difference between the current density and previous density values and the percent difference between these values (percent based on the density value).

Configuration Using the Wizard​

The configuration of the Meter's density comparison with default density 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 density comparison between cases.

    A Meters density comparison between cases - Attributes window opens.Figure 394: Meters density comparison between cases - Attributes window

  3. Select the Attributes according to the following table:

    Attributes

    SelectionsDescription
    DensityDensity attribute. Defaults to 'Density'.
    DifferenceEnter a value in the engineering unit of the Measured attribute.
    Percent DifferenceEnter a value in percent.
    StatusMeter in/out of service status. This defaults to 'ObjectStatus'.

  4. Enter the Difference and Percentage Difference thresholds.

  5. Click OK to finish the configuration.

    The text "CONFIGURED" displays next to the 'Meters density comparison between cases' selection.

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