Configure a one-time override

Follow this procedure to re-bracket individual points belonging to an alarm bracket set using a one-time override of an almbracket record's default positive and/or negative deviation limits.

Before you begin

Complete the steps in:

• Open the Bracket Control dialog

• Enable an almbracket record

To configure a one-time override

1. Navigate to the Bracket Control dialog box.

   Bracket Control dialog box - unrestricted limit setting

   

   Bracket Control dialog box - restricted limit setting

   

   If the Enabled checkbox on the right pane of the Bracket Control dialog box under Positive Deviation or Negative Deviation is selected, restrictions apply to the values you can enter for a one-time override of that particular limit. Under such conditions, you can only enter a limit that is less than, or equal to, the corresponding limit appearing on the right pane of the Bracket Control dialog box. In addition, the applicable Enabled and Is a Percentage checkboxes on the left pane are unavailable.

   If the Enabled checkbox on the right pane of the Bracket Control dialog box under Positive Deviation or Negative Deviation is not selected, there are no restrictions on the values you can enter for a one-time override of that particular limit. In addition, the applicable Enabled checkbox on the left pane becomes available. Once Enabled is selected, the associated Is A Percentage checkbox also becomes available.

   Note: Your administrative privileges has access to both panes of the Bracket Control dialog box (refer to Configure default deviation limits (Administrator only)).

2. Do one of the following:

   • To configure a one-time override of only the Negative Deviation limit, proceed to Step 3.

   • To configure a one-time override of the Positive Deviation limit, proceed as follows:

     1. If available and not already selected, select Enabled to have AVEVA Enterprise SCADA generate an alarm if the current value of the reference point rises above the Positive Deviation limit.

     2. If the checkbox is available, select Is A Percentage if the override value is a positive percentage amount of the reference value.

        The reference value is the bracketed value of the reference point above and below which the current value of the reference point oscillates.

        Note: A Reference Value column appears on the Alarm Bracket Summary window. For further information, refer to View points belonging to alarm bracket sets.

     3. In the value field, enter a value for the limit override as per the restriction rules noted above.

        This value is the amount by which the current value can exceed the reference value without generating an alarm.

     4. Do one of the following:

     • Proceed to Step 3 if configuring the Negative Deviation limit as well.

     • Select Re-bracket.

       If you select Re-bracket, the system refreshes the alarm state of the reference point when the re-bracketing operation finishes.

3. To configure a one-time override of the Negative Deviation limit, proceed as follows:

   1. If available and not already selected, select Enabled to have AVEVA Enterprise SCADA generate an alarm if the current value of the reference point falls below the Negative Deviation limit.

   2. If the checkbox is available, select Is A Percentage if the override value is a negative percentage amount of the reference value.

      The reference value is the bracketed value of the reference point above and below which the current value of the reference point oscillates.

      Note: A Reference Value column appears on the Alarm Bracket Summary window. For further information, refer to View points belonging to alarm bracket sets.

   3. In the value field, enter a value for the limit override as per the restriction rules noted above.

      This value is the amount by which the current value can fall below the reference value without generating an alarm.

   4. Select Re-bracket.

      The system refreshes the alarm state of the reference point when the re-bracketing operation finishes.