Configure the Main tab on the Accumulator record

The items on the Main tab of the accumulator Row Edit dialog are primarily designed to serve as an organizing tool, allowing you to define the group and dataset associated with the rate point used to gather accumulation information.

To configure the Main tab of the accumulator record

1. From the virtualflowcomputer Row Edit dialog of your desired record, create an accumulator record. For more information on creating an accumulator record, see Create an Accumulator record.

   The accumulator Row Edit dialog appears.

   

   Note: The Name and Virtual Flow Computer fields are read-only. These fields are populated when you create your accumulator record.

2. (Optional) In the Description field, enter a description.

3. In the Group field, click (...) to select a group. Group assignment will depend on which areas of control will provide view or control capability for this record.

4. In the Dataset field, click (...) to select a dataset. Dataset assignment will depend on how the records are to be grouped for control by distributed systems.

5. (Optional) In the Station field, click (...) to select an associated station record.

6. In the Meter Type field, click the dropdown to select the underlying meter device type. One of the following options can be selected:

   • Turbine

   • Orifice

   • Unspecified

7. In the Rate field, click (...) and select the name of the rate that will be providing the desired polled counter (Pulse or Pulse&Analog) or flow rate (Analog).

   • The Rate field is required for non-Orifice meters. For Orifice meters, you have the option to specify a Rate or a Deferential Pressure Analog. For more information, see Configure the Orifice tab on the Accumulator record.

8. In the Input Rollover field, enter the value at which you would like the input counter to roll over. For more information, see Understand the Accumulator's Input Rollover volume.

9. (Optional) In the Max Reasonable Flow Rate (vol/h) field, enter the maximum reasonable flow rate. All flow rate information is collected in the chosen units, per hour. If the Maximum Reasonable Flow Rate (vol/h) is exceeded, an anomalous condition will be detected. A Max Reasonable Flow Rate (vol/h) of zero will disable all flow rate checks.

   Note: Only a value between 0 and 100,000 may be entered in this field.

10. (Optional) In the Max Reasonable Reverse Flow Rate (vol/h) field, enter the maximum reasonable flow rate in situations when the accumulator is experiencing reverse flow.

    Note: Only a value between 0 and 100,000 may be entered in this field.

11. (Optional) In the Volume Accumulation Mode field, click the dropdown to select the volume accumulation mode. This dropdown menu enables you to determine whether negative volume accumulation will be tracked:

    • Positive Only—If Positive Only is selected, the accumulated volume will not decrease. If reverse flow occurs, as long as it is within the reasonable limits imposed by the Max Reasonable Reverse Flow Rate, the volume decrease is tracked internally by the VFC. However, it will not be reflected in the accumulator volume until enough forward flow has occurred to make up the temporary reverse flow.

      Note: If you are using a downstream pipeline that does not handle negative volume, then the accumulator should only be configured as Positive Only for the Volume Accumulation Mode.

    • Positive and Negative — Accumulated volume will increase with positive flow and decrease with reverse flow.

      Note: After observing a negative volume accumulation, if you switch the accumulation mode from Positive and Negative to Positive Only, the internal volume counters will reset to the last maximum value, resulting in an increase in volume on the accumulator.

12. In the Volume Update Timeout (sec) field, enter the timeout period, in seconds, after which the accumulator reading time will be updated if a volume change has not been observed. This setting assists the Max Reasonable Flow Rate (vol/h) check to identify acceptable volume and anomalous volume.

    The recommended value is the rate of volume update from the field device + the RTU Poll Delay value of the remote record. Both values should be in seconds. For example, if the field device updates volume every 60 seconds, and the remote record's RTU Poll Delay is five seconds, the recommended value is 65 seconds.

    Note: Only a value between 1 and 300 seconds may be entered in the field.

13. In the Bad Delta Expiry Timeout (sec) field, enter the timeout period, in seconds, after which the bad delta counter will return to zero in the event that the delta counter fails to increment or decrement. In other words, if there is no change in the counter's values and the timeout period passes, the bad delta counter will return to zero.

    Note: Only a maximum value of 3,600 seconds can be entered in the field.