Understand Pipeline Monitor (PLM) record quality

Pipeline Monitor (PLM) record quality is assessed only for the most recent minute.

Fresh Flag

The Pipeline Monitor (plm) record is set to stale if:

• The plm record is inhibited or suspended.

  OR

• For any meter, linefill, or tank device:

  • Has been stale longer than the configured Stale Time for the plm record.

  • Is not manual, or is manual and the Manual Value Ok flag for the device is not set.

If the plm record is stale, it will continue to do calculations but will not alarm on any balance limit violations, unless the Enable Stale Alarm field checkbox is selected.

Manual Flag

The Pipeline Monitor (plm) record is set to manual if any input device is in a manual state.

This flag has no real effect on plm processing.

Secondpoll Flag

The secondpoll flag is set to false for the Pipeline Monitor (plm) record if:

• Any error condition occurs in processing the plm record.

  OR

• Any linefill type input is stale and the following occurs:

  • It has been stale longer than the configured number of defined Stale Timeout (secs) for the record (This is configured on the Inhibits tab of the plm Row Edit dialog).

  • The Disable PLM Due to Linepack Stale checkbox has been selected on the Inhibits tab of the plm Row Edit dialog.

No PLM calculations are done whenever the secondpoll flag is false. The plm record will show Calculating no on the PLM Control display in easy eXtended Operator Station (ezXOS).

Error Flag

This is set to true if a data access error has occurred. For example, a missing referenced record or failure to lock a record can result in this flag being set.