FB_BA_Cont4Stp01

The function block FB_BA_Cont4Stp01 determines the resulting control steps of a multi-stage aggregate depending on the input signal.
Four switch-on thresholds and four hystereses can be parameterized.

Diagram 01

Control direction of parameter bActn = FALSE = Reverse = Heating

nStp	nNumOfStp	fSwiOn	fSwiOff	nRemTiDlyOn	nRemTiDlyOff	bQ01	bQ02	bQ03	bQ04
0	0	fSwiOn01	fSwiOn01 - fHys01	nDlyOn01	0	FALSE	FALSE	FALSE	FALSE
1	>= 1	fSwiOn02	fSwiOn01 - fHys01	nDlyOn02	nDlyOff01	TRUE	FALSE	FALSE	FALSE
2	>= 2	fSwiOn03	fSwiOn02 - fHys02	nDlyOn03	nDlyOff02	TRUE	TRUE	FALSE	FALSE
3	>= 3	fSwiOn04	fSwiOn03 - fHys03	nDlyOn04	nDlyOff03	TRUE	TRUE	TRUE	FALSE
4	>= 4	fSwiOn04	fSwiOn04 - fHys04	0	nDlyOff04	TRUE	TRUE	TRUE	TRUE

Diagram 02

Control direction parameter bActn = TRUE = Direct = Cooling

nStp	nNumOfStp	fSwiOn	fSwiOff	nRemTiDlyOn	nRemTiDlyOff	bQ01	bQ02	bQ03	bQ04
0	0	fSwiOn01	fSwiOn01 + fHys01	nDlyOn01	0	FALSE	FALSE	FALSE	FALSE
1	>= 1	fSwiOn02	fSwiOn01 + fHys01	nDlyOn02	nDlyOff01	TRUE	FALSE	FALSE	FALSE
2	>= 2	fSwiOn03	fSwiOn02 + fHys02	nDlyOn03	nDlyOff02	TRUE	TRUE	FALSE	FALSE
3	>= 3	fSwiOn04	fSwiOn03 + fHys03	nDlyOn04	nDlyOff03	TRUE	TRUE	TRUE	FALSE
4	4	fSwiOn04	fSwiOn04 + fHys04	0	nDlyOff04	TRUE	TRUE	TRUE	TRUE

Diagram 03

Timing of the switch-on and switch-off delays

At time t1 fIn jumps from fSwiOn01 to fSwiOn04

At time t2 fIn jumps from fSwiOn04 to fSwiOn01 - fHys01

Inputs

VAR_INPUT
  bEn             : BOOL;
  fIn             : REAL;
  fSwiOn01        : REAL
  fHys01          : REAL;
  nDlyOn01        : UDINT;
  nDlyOff01       : UDINT;
  fSwiOn02        : REAL;
  fHys02          : REAL;
  nDlyOn02        : UDINT;
  nDlyOff02       : UDINT;
  fSwiOn03        : REAL;
  fHys03          : REAL;
  nDlyOn03        : UDINT;
  nDlyOff03       : UDINT;
  fSwiOn04        : REAL;
  fHys04          : REAL;
  nDlyOn04        : UDINT;
  nDlyOff04       : UDINT;
  nNumOfStp       : UDINT;
  bActn           : BOOL;
END_VAR

Name	Type	Description
bEn	BOOL	General enable of the function block. If bEn is FALSE, all outputs are set to 0.
fIn	REAL	Input value, from which the switching state is derived.
fSwiOn01	REAL	Switch-on point step 01
fHys01	REAL	Absolute value hysteresis step 01
nDlyOn01	UDINT	Start-up delay step 01
nDlyOff01	UDINT	Switch-off delay step 01
fSwiOn02	REAL	Switch-on point step 02
fHys02	REAL	Absolute value hysteresis step 02
nDlyOn02	UDINT	Start-up delay step 02
nDlyOff02	UDINT	Switch-off delay step 02
fSwiOn03	REAL	Switch-on point step 03
fHys03	REAL	Absolute value hysteresis step 03
nDlyOn03	UDINT	Start-up delay step 03
nDlyOff03	UDINT	Switch-off delay step 03
fSwiOn04	REAL	Switch-on point step 04
fHys04	REAL	Absolute value hysteresis step 04
nDlyOn04	UDINT	Start-up delay step 04
nDlyOff04	UDINT	Switch-off delay step 04
nNumOfStp	UDINT	Input of the number of steps required. The input is limited from 0 to 4.
bActn	BOOL	Input variable with which the control direction of the step switch is determined. TRUE = Direct = Cooling; FALSE = Reverse = Heating

Outputs

VAR_OUTPUT
  bQ01               : BOOL;
  bQ02               : BOOL;
  bQ03               : BOOL;
  bQ04               : BOOL;
  nStp               : UDINT;
  fSwiOn             : REAL;
  fSwiOff            : REAL;
  nRemTiDlyOn        : UDINT;
  nRemTiDlyOff       : UDINT;
END_VAR

Name	Type	Description
bQ01	BOOL	Display of status step 01 TRUE = ON; FALSE = OFF nStp >= 1
bQ02	BOOL	Display of status step 02 TRUE = ON; FALSE = OFF nStp >= 2
bQ03	BOOL	Display of status step 03 TRUE = ON; FALSE = OFF nStp >= 3
bQ04	BOOL	Display of status step 04 TRUE = ON; FALSE = OFF nStp >= 4
nStp	UDINT	Shows the current step of the step switch
fSwiOn	REAL	Shows the next switch-on point
fSwiOff	REAL	Shows the next switch-off point
nRemTiDlyOn	UDINT	If the switch-on point for switching to the next level is met, the progress of the switch-on delay time is displayed here.
nRemTiDlyOff	UDINT	If the switch-off point for switching down to the next level is met, the progress of the switch-off delay time is displayed here.

Requirements

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