FB_BA_AnalogValue

The function block FB_BA_AnalogValue is used to operate or monitor an analog setpoint.

Within the parameters, it is possible to activate upper (stHighLimit) and lower (stLowLimit) limit value monitoring of the output signal fPresentValue.

In addition, the function block can be provided with a PT-1 filter to avoid strong fluctuations and jumps caused by the input signal fValue. The filter is activated by adjusting the filter constants nDampingConstant > 0.

Syntax

FUNCTION_BLOCK FB_BA_AnalogValue
VAR_INPUT
  fValue              : REAL;
END_VAR
VAR_INPUT CONSTANT PERSISTENT
  {region 'Variable Parameters'}
    {attribute 'parameterCategory':='Hardware'}
    fOffset           : REAL;
    {attribute 'parameterCategory':='EventConfig'}
    stHighLimit       : ST_BA_LimitParameter := (nTimeToAbnormal := 1, nTimeToNormal := 1);  
    {attribute 'parameterCategory':='EventConfig'}
    stLowLimit        : ST_BA_LimitParameter := (nTimeToAbnormal := 1, nTimeToNormal := 1);
    {attribute 'parameterCategory':='Value'}       
    nDampingConstant  : UDINT := 0;  
  {endregion}
END_VAR
VAR_OUTPUT
  fPresentValue       : REAL;
  bHighLimit          : BOOL;
  bLowLimit           : BOOL;
END_VAR

Inputs

Name	Type	Description
fValue	REAL	Input value from the process.

Inputs CONSTANT PERSISTENT

Name	Type	Description
fOffset	REAL	The offset can be used to adjust the scaled output value fPresentValue.
stHighLimit	ST_BA_LimitParameter	Data and command structure for upper limit value monitoring.
stLowLimit	ST_BA_LimitParameter	Data and command structure for lower limit value monitoring.
nDampingConstant	UDINT	To avoid strong fluctuations and jumps in the input signal, the function block is provided with a PT1 filter. This filter is activated by setting the filter constant nDampingConstant to greater than 0.

Outputs

Name	Type	Description
fPresentValue	REAL	Output value.
bHighLimit	BOOL	The upper limit monitoring is active.
bLowLimit	BOOL	The lower limit monitoring is active.

Prerequisites

Development environment	Required PLC library
TwinCAT from v3.1.4024.62	Tc3_BA2 from v5.5.14.0