PDBC status and parameter values

Use the
General
 tab on the
PDBC Properties
 dialog box to monitor the instruction status and set parameter values for the instruction.
To monitor the instruction status and set parameter values 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. Configure these settings, which are enabled when online with the controller:
    • Drive PV lower at
      . The threshold setting that triggers lowering. When the PV is greater than this threshold, the Lower output is energized to drive equipment to reduce the PV.
    • Drive PV higher at
      . The threshold setting that triggers raising. When the PV is less than this threshold, the Raise output is energized to drive equipment to increase the PV.
      For more information on thresholds and deadbands, see Thresholds and deadbands in Process Deadband Controller (PDBC) instructions.
  3. When online with the controller, use the
    Online commands
     buttons to adjust the output value and change the command mode. The action is immediate if the command request does not need to be confirmed by the operator. If the command request requires a signature, this will enforce security from the HMI and disable the command from the Logix Designer dialog.
    • Online command: Raise
      . Energizes the
      Raise
      output in manual mode to drive equipment to increase the PV.
    • Online command: Stop
      . Clears the
      Raise
      and
      Lower
      outputs in manual mode.
    • Online command: Lower
      . Energizes the
      Lower
      output in manual mode to drive equipment to reduce the PV.
    • Online command: Auto
      . Changes the mode to auto. In Automatic Loop Mode, the outputs are triggered by the control algorithm to keep the PV within limits.
    • Online command: Manual
      . Changes the mode to manual. In Manual Loop Mode, the operator directly manipulates the Raise and Lower outputs from the HMI.
  4. Monitor device status:
    • 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
    • PV Low deviation threshold
      . If the PV is below the Raise threshold by more than this amount, a low deviation status is triggered.
    • PV High deviation threshold
      . If the PV is above the Lower threshold by more than this amount, a high deviation status is triggered.
    • High decrease rate
      . If the rate of decrease of the PV exceeds this threshold, a high rate of change decreasing status is triggered.
    • High increase rate
      . If the rate of increase of the PV exceeds this threshold, a high rate of change increasing status is triggered.
    • PV input and output values
      . Displays the value of the .Inp_PV member of the tag (input) and the value of the .Val_PV member of the tag (output).
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