Description
Original instructions
Function description
The function block forms a two-point controller, which maintains PID-similar behavior through two dynamic feedback paths.
EN and ENO can be configured as additional parameters.
Properties
The function block has the following properties:
Representation in FBD
Representation:
Representation in LD
Representation:
Representation in IL
Representation:
CAL PCON2_Instance (SP:=SetpointInput, PV:=ProcessVariable, 
    MODE:=OperatingModes, PARA:=Parameter, 
    YMAN:=ManualManipulated_ERR_EFF, 
    Y=>ManipulatedOutput, ERR_EFF=>EffectiveError)
Representation in ST
Representation:
PCON2_Instance (SP:=SetpointInput, PV:=ProcessVariable, 
    MODE:=OperatingModes, PARA:=Parameter, 
    YMAN:=ManualManipulated_ERR_EFF, 
    Y=>ManipulatedOutput, ERR_EFF=>EffectiveError) ;
PCON2 parameter description
Description of input parameters:
Parameter
Data type
Description
SP
Setpoint input
PV
REAL
Actual value input
MODE
Operating mode
PARA
Parameter
YMAN
"1" = Manual value for ERR_EFF
Description of output parameters:
Parameter
Data type
Description
Y
BOOL
"1" = Output manipulated variable
ERR_EFF
REAL
Effective switch value
Parameter description Mode_MH
Data structure description
Element
Data type
Description
man
"1" = Manual mode
halt
BOOL
"1" = Halt mode
Parameter description Para_PCON2
Data structure description
Element
Data type
Description
gain
Feedback boost
lag_neg
Time constants of the quick feedback
lag_pos
TIME
Time constants of the slow feedback
hys
REAL
Hysteresis from two point switch
xf_man
REAL
Reset value of the feedback in % (0 – 100)
Runtime error
In the following cases a warning is given:
Causes
Behavior of the controller
lag_neg = 0 and lag_pos > 0
The controller works as if it had only a negative feedback with time constant lag_pos.
lag_pos < lag_neg > 0
The controller works as if it had only a negative feedback with time constant lag_neg.
xf_man < 0 or xf_man > 100
The controller works without internal feedback paths.
NOTE: For a list of all block error codes and values, see CLC_PRO.