Configure default deviation limits (Administrator only)

Follow this procedure to configure an almbracket record's default positive and/or negative deviation limits. The default limits remain in place after a re-bracketing operation.

Before you begin

Complete the steps in:

• Open the Bracket Control dialog

• Enable an almbracket record

  Note: You can configure default deviation limits only with your administrative privileges.

To configure default deviation limits

1. Navigate to the Bracket Control dialog box.

   

2. Select Default Limits.

3. To configure a default Positive Deviation limit, proceed as follows:

   1. Select Enabled.

   2. Select Is A Percentage if the 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 the amount by which the current value can exceed the reference value without generating an alarm. Depending on whether or not Is a Percentage is selected, the system calculates the Positive Deviation limit as per one of the following formulas:

      • Value: reference value + value/percentage.

      • Percentage: (value/percentage x reference value)/ 100 + reference value.

      If the reference value is negative, the system calculates the Positive Deviation limit as per one of the following formulas:

      • Value: reference value + value/percentage.

      • Percentage: reference value - (value/percentage x reference value)/ 100.

4. To configure a default Negative Deviation limit, proceed as follows:

   1. Select Enabled.

   2. Select Is A Percentage if the 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 the amount by which the current value can fall below the reference value without generating an alarm. Depending on whether or not Is a Percentage is selected, the system calculates the Negative Deviation limit as per one of the following formulas:

      • Value: reference value - value/percentage.

      • Percentage: reference value - (value/percentage x reference value)/ 100.

      If the reference value is negative, the system calculates the Negative Deviation limit as per one of the following formulas:

      • Value: reference value - value/percentage.

      • Percentage: (value/percentage x reference value)/ 100 + reference value.