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AVEVA Enterprise SCADA

FlowTotalConfig Row Edit: Calc​. Element [0-3] tabs

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FlowTotalConfig Row Edit: Calc​. Element [0-3] tabs

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  • Last UpdatedApr 24, 2025
  • 6 minute read

Use the Calc. Element [0-3] tabs in the flowTotalConfig Row Edit dialog box to configure the calculation and alarming properties of the flowTotalConfig record's elements.

Refer to the table below for field descriptions and instructions on how to configure the editable fields.

Note: The items are the same on all four Calc. Element tabs.

Important: When you configure or modify the alarm limits and/or inhibits of a flowTotalConfig record associated with an almlimit record (identified in the Alarm Limit Set field), the system transfers settings from the following sections to the almlimit record as well as any analog, rate, or flowTotalConfig records also associated with that almlimit record:

  • State Alarming Inhibit

  • Level Alarming

  • Rate of Change Alarming

  • Creep Alarming

  • Flatline Alarming

    Item

    Description

    Base Message

    Select (...) and select the message associated with the element from the Message Select dialog box.

    For information on configuring message records, refer to RealTime tables.

    Enable calculation

    Select yes to enable calculation of this element's value.

    Calculate Averages

    Select to have the Monitor process calculate the average value for the element. You can make these averages available for reports, displays, and applications.

    Enable Integration

    Select to have the Monitor process calculate the total quantity (for example, volume) over a given time period.

    Integration Scale

    This factor is used to scale the accumulated quantity such that:

    Where:

    • t = the time measured in milliseconds.

    • currentflow = the flow total rate measured in units per hour.

      For example, the scaling factor should be 1.0 if the rate directly corresponds to hourly accumulated quantity (for example, barrels per hour).

    State Alarming Inhibit

    Select the states on which to inhibit alarms.

    Enable

    This field applies to Offscan Integration.

    Select to have the Monitor process calculate the total quantity using the following formula when one of the associated data sources goes offscan:

    VNFT = (VPFT + (VAnalog x (DeltaTime/3600000))

    Where:

    • VNFT = Net Flow Total value.

    • VPFT = Previous Flow Total value.

    • VAnalog = Analog Rate Source.

    • DeltaTime = Time difference in milliseconds since last processing of data.

      Note: If Enable is selected on any of the Calc. Element tabs, the application prevents all Calculate Averages and Enable Integration calculations from occurring, regardless of whether or not those two checkboxes are selected on any of the tabs.

    Analog Rate Source

    Enter or select the name of the analog record used as a rate in the Offscan Integration equation described in the row above.

    Top of Day Rollover Enable

    Select to roll over the flowTotalConfig record at the Top of Day (24hr) hour (the system resets the Offscan Integration value to zero).

    Top of Day (24hr)

    Enter the hour of the day at which to roll over the flowTotalConfig record.

    Priority Display

    Specify the graphic you want to be associated with the priority display button on an easy eXtended Operator Station (ezXOS) control dialog box.

    Off-Normal Alarm

    Select the checkbox to inhibit off-normal alarming. The system will not generate an alarm when the point changes from a normal state to an off-normal state.

    Normal Alarm

    Select the checkbox to inhibit normal alarming. The system will not generate an alarm when the point changes from an off-normal state to a normal state.

    Off-Normal Log

    Select the checkbox to inhibit off-normal logging. The system will not log an event when the point changes from a normal state to an off-normal state.

    Normal Log

    Select the checkbox to inhibit normal logging. The system will not log an event when the point changes from an off-normal state to a normal state.

    Minimum (EGU)

    Enter the lowest measurable value of the instrument in engineering units (EGUs).

    For example, if a temperature instrument is rated as measuring between -40 °C and 160 °C, set the Minimum (EGU) to -40 and set the Maximum (EGU) to 160.

    The EGU values are used in EGU conversion.

    Maximum (EGU)

    Enter the highest measurable value of the instrument in EGUs.

    For example, if a temperature instrument is rated as measuring between -40 °C and 160 °C, set the Minimum (EGU) to -40 and set the Maximum (EGU) to 160.

    The EGU values are used in EGU conversion.

    Units

    This is a text string that describes the EGUs that are measured by this point (for example, "barrels", "BBLS", "kV", "PSI", etc.). This string appears in the ezXOS displays. It is used for display purposes only and has no effect on any system calculations.

    Alarm Deadband

    Enter the alarm deadband value for the flowTotalConfig point.

    HiHi Alarm Check

    Select to edit the HighHigh alarm limits. For more information, refer to RealTime tables.

    Hi Alarm Check

    Select to edit the High alarm limits. For more information, refer to RealTime tables.

    Lo Alarm Check

    Select to edit the Low alarm limits. For more information, refer to RealTime tables.

    LoLo Alarm Check

    Select to edit the LowLow alarm limits. For more information, refer to RealTime tables.

    HiHi Alarm Limit

    Enter the HighHigh alarm limit for the flowTotalConfig point.

    Hi Alarm Limit

    Enter the High alarm limit for the flowTotalConfig point.

    Lo Alarm Limit

    Enter the Low alarm limit for the flowTotalConfig point.

    LoLo Alarm Limit

    Enter the LowLow alarm limit for the flowTotalConfig point.

    User High Alarm Check

    Refer to User Configurable Alarm Limits.

    User Hi Alarm Limit

    User Lo Alarm Check

    User Lo Alarm Limit

    Enable ROC Alarm

    Select to enable the Rate Of Change (ROC) alarm. If the rate of change exceeds the configured rate of change limits, the system generates an alarm.

    For further information, refer to RealTime tables.

    ROC Type

    Select the type of ROC alarming to use.

    Options:

    • baseline method – use the baseline method of ROC alarming

    • custom method – use the baseline method of ROC alarming with the additional fields below:

      • Negative Rate of change limit

      • Time Interval for ROC

        In the baseline method, the system calculates the rate of change as the difference between the current and previous poll, divided by the difference in time between these consecutive polls. This yields a rate in EGUs per second, which the system then compares against the ROC limit. The system generates an alarm if either positive or negative ROC occurs.

        The custom method works to reduce nuisance alarms by allowing you to specify the delta time between values, as opposed to the system calculating the ROC between consecutive polls. In addition, the custom method allows for different ROC limits for positive and negative ROC.

        The system calculates custom ROC by recording multiple poll cycles (up to 30) and calculating the ROC between values that are separated in time by at least the delta time value that you specify (Time Interval for ROC):

        ROC = (Current Value - Value at Delta Time ago) / Delta Time

        Where:

        Delta Time = Time Interval for ROC.

        It is best to set the Delta Time to a multiple of the poll cycle time. For example, if poll cycles are 10 seconds, set the Delta Time to a value divisible by 10.

        Note: Baseline alarms are not persistent. However, Custom ROC alarms are persistent. Subsequent to a Custom ROC alarm, the system continues to calculate the ROC each poll using the above method, and maintains the alarm state so long as the ROC over the Delta Time exceeds limits. For custom ROC alarms, once the limit is no longer exceeded, a return-to-normal alarm will be generated.

    Rate of change limit (Units/Sec)

    Enter the maximum, positive allowable ROC (EGUs per second).

    Negative Rate of change limit (Units/Sec)

    Enter the maximum, negative allowable ROC (EGUs per second).

    Time Interval for ROC (sec)

    Enter the time interval over which the system should calculate the ROC.

    Flatline Alarming

    Select to enable Flatline Alarming. If the flowTotalConfig value does not change within the Timeout value (min), an alarm is generated.

    Timeout value (min)

    Enter the maximum about of time (minutes) that can pass without the flowTotalConfig value changing.

    Creep Detection

    Select to enable the Creep Detection alarm. If the almlimit value creeps out of its calibrated state by a value that exceeds the creep Deviation Alarm Limit, the system generates an alarm.

    For further information, refer to RealTime tables.

    Deviation Alarm Limit

    Enter the maximum deviation value (EGUs) that is acceptable before calibration deteriorates.

    Enable Alternate Alarm Limit

    Refer to Alternate Alarm Limits.

    Alarm Limit Set