Alarm conditions for PDBC

Use the
Alarms
tab on the
PDBC Properties
 dialog box to set the values that define alarm conditions for the instruction.
Define alarm conditions for Process Deadband Controller (PDBC) instructions
  1. On the instruction in the routine, perform one of these actions:
    • On the Ladder or FBD instruction, select .
    • In the Structured Text editor, right-click the tag name and select
      Configure <tag name>
      .
  2. Select the
    Alarms
     tab.
  3. Configure these settings:
    • Use Alarm
      . Select to use an alarm. Alarm conditions are not evaluated when an alarm is not in use.
    • Alarm Name
      . Enter the label to display for the associated alarm.
    • Gate delay
      . The alarm condition detection is enabled or gated by the gate signal. Gate signals are inputs of the PDBC instruction. Enter a delay in seconds to set the delay for High deviation, Low deviation, High rate of change increasing, and High rate of change decreasing detection.
    • Limit
      . The PV deviation threshold or rate of change threshold for triggering the alarm.
    • Deadband
      . Sets the deadband around the limit. The deadband defines a range above or below the limit to prevent unwanted rapid switching of the status.
    • State
      . The state of the alarm. Hover over the state icon to see a tool tip that describes the alarm state or fault status.
      An alarm can be in more than one state at a time. For example, an alarm can be in alarm, acknowledged, and suppressed; or normal, unacknowledged, and suppressed.
      Alarm state icons include:
      • Normal, acknowledged (no icon).
      • Normal, unacknowledged - NormalAlarmUnacknowledged
      • In alarm, acknowledged - InAlarmAcknowledged
      • In alarm, unacknowledged - InAlarmUnacknowledged
      • Suppressed - AlarmSuppressed
      • Shelved - AlarmShelved
      • Disabled - Alarm Disabled icon
      • Alarm fault - AlarmFault
  4. To open the
    Alarm Properties
     dialog box for the alarm, select the
    Configuration
    icon .
  5. To configure settings for all pre-defined alarms for a PDBC instruction, select
    Settings for all alarms
    . When this box is checked, changes made to these settings are applied to all pre-defined alarms:
    • Class
      . A group name for related alarms. The class does not limit the alarms that an Alarm Summary object subscribes to. Use
      Class
      to filter the alarms that are displayed to the operator.
    • Alarm group
      . A group name to help classify and sort alarms.
    • FactoryTalk View
       command
      . A
      FactoryTalk View
       command that can be run on the operator station when the alarm notification appears. Enter the exact syntax for the
      FactoryTalk View
       command.
  6. To allow an operator to shelve an alarm, select
    Allow operator to shelve alarm
    .
  7. To allow maintenance technicians to disable an alarm, select
    Allow maintenance to disable alarm
    .
  8. When online with the controller, monitor the
    Device state
    ,
    Device issues
    , and
    Device mode
     indicators at the bottom left of the dialog box:
    • Device state
      . When the
      Logix Designer
       application is online with the controller, displays the current device state:
      • Deadband, Q is off
      • Deadband, Q is on
      • Above Lower setpoint
      • Below Raise setpoint
      • Same in manual
      • Out of service
    • Device issues
      . When the
      Logix Designer
       application is online with the controller, displays fault status:
      • None
      • Low deviation
      • High deviation
      • High rate of change (decreasing)
      • High rate of change (increasing)
      • Input source bad
      • Configuration error
    • Device mode
      . When the
      Logix Designer
       application is online with the controller, displays the current device mode:
      • Auto
      • Manual
      • Normal
  9. Select
    Apply
    .
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