PPID shed settings

Use the
Sheds
tab on the
PPID Properties
 dialog box to configure shed settings for Process Proportional + Integral + Derivative (PPID) instructions.
To configure shed settings for PPID 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. Under
    Advanced
    , select the
    Sheds
    tab.
  3. Select the shed settings for a CV fail:
    • Latch shed action until reset
      . Select to latch the CV, SP, and loop mode shed actions triggered by CV fail.
    • CV action
      . Select the shed action for the CV when the CV fails:
      Hold last CV
       or
      Use shed CV
      .
    • SP action
      . Select the shed action for the SP when the CV fails:
      No action
      ,
      Hold last SP
      ,
      Use shed SP
      , or
      Use last PV
      .
    • Loop mode action
      . Select the shed action for the loop mode when CV fails:
      No action
      ,
      Manual
      , or
      Auto/Manual
      .
  4. Select the shed settings for a PV fail:
    • Latch shed action until reset
      . Select to latch the CV, SP, and loop mode shed actions triggered by PV fail.
    • CV action
      . Select the shed action for the CV when the PV fails:
      Hold last CV
       or
      Use shed CV
      .
    • SP action
      . Select the shed action for the SP when the PV fails:
      No action
      ,
      Hold last SP
      ,
      Use shed SP
      .
    • Loop mode action
      . Select the shed action for the loop mode when PV fails:
      No action
      ,
      Manual
      , or
      Auto/Manual
      .
  5. Select the shed settings for an SP fail:
    • Latch shed action until reset
      . Select to latch the CV, SP, and loop mode shed actions triggered by SP fail.
    • CV action
      . Select the shed action for the CV when the SP fails:
      No action
      ,
      Hold last CV
      ,
      or
      Use shed CV
      .
    • SP action
      . Select the shed action for the SP when the SP fails:
      Hold last SP
      ,
      Use shed SP
      , or
      Use last PV
      .
    • Loop mode action
      . Select the shed action for the loop mode when SP fails:
      No action
      ,
      Manual
      , or
      Auto/Manual
      .
  6. Select the shed settings for Interlock not OK:
    • Latch shed action until reset
      . Select to latch the CV, SP, and loop mode shed actions triggered by Interlock not OK.
    • CV action
      . Select the shed action for the CV on Interlock not OK:
      No action
      ,
      Hold last CV
      , or
      Use shed CV
      .
    • SP action
      . Select the shed action for the SP on Interlock not OK:
      No action
      ,
      Hold last SP
      ,
      Use shed SP
      , or
      Use last PV
      .
    • Loop mode action
      . Select the shed action for the loop mode on Interlock trip:
      No action
      ,
      Manual
      , or
      Auto/Manual
      .
  7. Select the shed values for CV and SP:
    • Shed value for CV
      : Enter or monitor the value to be used for the CV when shed CV is selected as CV action.
    • Shed value for SP
      : Enter or monitor the value to be used for the SP when shed SP is selected as SP action.
  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, such
      SP ramping
       or
      CV held
      .
    • Device issues
      . When the
      Logix Designer
       application is online with the controller, displays fault conditions, such as
      PV uncertain
      ,
      SP fail
      , or
      Configuration error
      .
    • Device mode
      . When the
      Logix Designer
       application is online with the controller, displays the current device mode:
      • Manual
      • Auto
      • Cascade (no Ratio)
      • Ratio
  9. Select
    Apply
    .
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