FB_BA_Loop

The function block FB_BA_Loop represents a PID controller within the project structure of TF8040.

Functional diagram

The controller can be operated either in parallel structure or with upstream P part. This is specified by the input eOpMode.

Upstream P part:

eOpMode := E_BA_PIDMode. eP1ID

Parallel structure:

eOpMode := E_BA_PIDMode. ePID

Inheritance hierarchy

FB_BA_Base

FB_BA_BasePublisher

FB_BA_Object

Illustration

FUNCTION_BLOCK FB_BA_Loop EXTENDS FB_BA_Object IMPLEMENTS I_BA_Loop
VAR_INPUT
  bEn                        : BOOL;
  fSetpoint                  : REAL;
  fCtrlVal                   : REAL;
  eActionPgm                 : E_BA_Action;
  fMinOutputPgm              : REAL;
  fMaxOutputPgm              : REAL;
  bEnSync                    : BOOL;
  fValSync                   : REAL;
END_VAR
VAR_OUTPUT
  fPresentValue              : REAL;
END_VAR
VAR_INPUT CONSTANT PERSISTENT
  {region 'Variable Parameters'}
    eOutputUnit              : E_BA_Unit := E_BA_Unit.eOther_Percent;
    fCOVIncrement            : REAL := BA_Param.fDefCOVIncrement;
    eOpMode                  : E_BA_PIDMode := BA_Param.nLoop_DefOpMode;
    eActionRm                : E_BA_Action := E_BA_Action.eDirect;
    fNeutralZone             : REAL:= 0;
    fMinOutputRm             : REAL:= 0;
    fMaxOutputRm             : REAL:= 100;
    fProportionalConstant    : REAL;
    fIntegralConstant        : REAL;
    fDerivativeConstant      : REAL := 0;
    nDampConstant            : UDINT;
    stStepDelay              : ST_BA_StepDelayParam;
  {endregion}
END_VAR
VAR
  {region 'Output-Properties'}
    fCtrlDeviation           : REAL;
{endregion}
  END_VAR
VAR
  {region 'Hardware'}
    eActionSource            : E_BA_ProcessSignalSource;
    eMinMaxOutputSource      : E_BA_ProcessSignalSource;
  {endregion}
END_VAR

Inputs

Name	Type	Description
bEn	BOOL	Activation of the function block.
fSetpoint	REAL	Setpoint
fCtrlVal	REAL	Feedback of the control value for calculating the control deviation from the setpoint.
eActionPgm	E_BA_Action	Setting the control direction.
fMinOutputPgm	REAL	Lower controller output limit.
fMaxOutputPgm	REAL	Upper controller output limit.
bEnSync	BOOL	Enable synchronization.
fValSync	REAL	Synchronization value. After a positive edge at bEnSync this value is written to fPresentValue.

Outputs

Name	Type	Description
fPresentValue	REAL	Current analog output value of the object.

Inputs CONSTANT PERSISTENT

Name	Type	Description
eOutputUnit	E_BA_Unit	Output unit
fCOVIncrement	REAL	Step size of the Present Value that triggers a COV Notification.
eOpMode	E_BA_PIDMode	Pre- or parallel-set P part.
eActionRm	E_BA_Action	Control direction
fNeutralZone	REAL	Neutral zone
fMinOutputRm	REAL	Minimum output value due to external override.
fMaxOutputRm	REAL	Maximum output value due to external override.
fProportionalConstant	REAL	Proportional constant.
fIntegralConstant	REAL	Integral constant.
fDerivativeConstant	REAL	Derivative constant.
nDampConstant	UDINT	Damping constant.

VAR

Name	Type	Description
fCtrlDeviation	REAL	Control deviation
eActionSource	E_BA_ProcessSignalSource	Definition of whether the control direction is to be treated as a variable or as a parameter.
eMinMaxOutputSource	E_BA_ProcessSignalSource	Definition whether the output source is to be treated as a variable or as a parameter.

Requirements

Development environment	Required PLC library
TwinCAT from v3.1.4024.35	Tc3_XBA from v5.3.0.0