FB_BA_SlidingLimitCtrl

The function block FB_BA_SlidingLimitCtrl is used to monitor a sliding setpoint.
The input bEn is used for general enabling of the function block.

To check the function of a control system, the actual value is compared with the setpoint of the controlled system.
If the deviation between the setpoint and the actual value is within the tolerance range fHys, then the control system is OK. If the actual value deviates from the setpoint by an amount outside this tolerance range over an extended period, the timer nDelay is started. After the timer has expired, if the control deviation remains, either the output bLowLimit or bHighLimit TRUE of the function block outputs a message.

Inputs

VAR_INPUT
  bEn          : BOOL;
  fW           : REAL;
  fX           : REAL;
  fHys         : REAL;
  nDelay       : UDINT;
ENDVAR

Name	Type	Description
bEn	BOOL	General enable of the function block. If bEn is FALSE, the message outputs bHighLimit and bLowLimit are also FALSE.
fW	REAL	Setpoint
fX	REAL	Actual value
fHys	REAL	Hysteresis
nDelay	UDINT	Response delay [s] of the outputs bHighLimit/bLowLimit. The input of the time is limited to the global parameter BAComn_Global.udiMaxSecInMilli from the Tc3_BA2_Common library (see BAComn_Global).

Outputs

VAR_OUTPUT
  bHighLimit         : BOOL;
  bLowLimit          : BOOL;
  fHighLimit         : REAL;
  fLowLimit          : REAL;
  nRemTiDelay        : UDINT;
END_VAR

Name	Type	Description
bHighLimit	BOOL	Upper limit value reached.
bLowLimit	BOOL	Lower limit value reached.
fHighLimit	REAL	Output of the upper limit value. fHighLimit = fW + (fHys / 2)
fLowLimit	REAL	Output of the lower limit value. fLowLimit = fW - (fHys / 2)
nRemTiDelay	UDINT	Remaining time after exceeding a limit value until one of the outputs bHighLimit or bLowLimit is set. The default comes from nDelay.

Requirements

Development environment	Required PLC library
TwinCAT from v3.1.4024.22	Tc3_BA2 from v5.2.5.0