PPID setpoint source and clamping limits

Use the
SP
tab on the
PPID Properties
 dialog box to monitor the source and processing of the setpoint value and to configure the setpoint clamping limits for Process Proportional + Integral + Derivative (PPID) instructions.
To monitor the setpoint source and configure setpoint clamping limits
  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 the
    General
    tab, select the
    SP
    tab.
  3. In the
    Operator Setpoint/Ratio value
     box, enter or monitor the setpoint (SP) or ratio value from the operator. This parameter is used for the ratio value when the loop mode is configured as
    Cascade
    and the instruction is configured for
    Ratio
    . If the setting requires a signature, this will enforce security from the HMI and disable the setting from the Logix Designer dialog.
    NOTE: Use the
    HMI
    tab to assign a unit label for the SP units on this tab.
  4. In the
    SP clamping limits
     boxes, enter the high and low clamping limits. Use this numerical entry to check or set the high and low limit value at which the SP is clamped.
  5. Monitor these parameters:
    • 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
    • Program Setpoint/Ratio value
      . Displays the Program defined setpoint or ratio value. This parameter is used for the ratio value when the loop mode is configured as
      Cascade
      and the instruction is configured for
      Ratio
      .
    • External Setpoint/Ratio value
      . Displays the Externally defined setpoint or ratio value. This parameter is used for the ratio value when the loop mode is configured as
      Cascade
      and the instruction is configured for
      Ratio
      .
    • Override Setpoint/Ratio value
      . Displays the setpoint or ratio value supplied in Override. This parameter is used for the ratio value when the loop mode is configured as
      Cascade
      and the instruction is configured for
      Ratio
      .
    • SP ramp wizard
      . Displays the status of Setpoint ramp wizard function. The ramp wizard function can be in progress, enabled, or disabled. Ramping is not available when the instruction is configured for
      Ratio
      .
      Use the
      Advanced
      tab to enable the ramp wizard. Use the
      SP ramp
       tab to enter target ramp values and to start and stop ramping.
    • Current ratio
      . Displays the actual ratio value from the in-service source after clamping.
    • Cascade SP
      . Displays the actual value from Inp_CascSP. When the loop mode is set to
      Cascade
      , this input is a setpoint from the outer loop. When the loop mode is set to
      Cascade
      and the instruction is configured for
      Ratio
      , this input is a process variable.
    • Current SP rate of change limits
      . Displays the SP rate-of-change limits. Use the
      Advanced > Limits
       tab to set the SP rate-of-change limits. The limit values can either be configured on the
      Limits
      tab or can be calculated by the SP ramp wizard when the wizard starts.
    • Current PV
      . Displays the value from Inp_PV which is used as a setpoint if the original SP cannot be used and the instruction is configured for this shed. Use the
      Advanced
      tab and the
      Advanced > Loop
       mode tab to configure the conditions that trigger SP by PV replacement.
    • Interlock SP
      . Displays the value from Cfg_SPIntlk which is used as a setpoint if the original SP cannot be used and the instruction is configured for this shed in interlock. Use the
      Advanced > Loop
       mode tab to configure the conditions that trigger SP by PV replacement.
    • Target for SP
      . Displays the target SP value before ramping.
    • Current SP
      . Displays the SP value after ramping, Val_SP. Val_SP provides SP value to the PID formula.
  6. Select
    Apply
    .
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