XFC_PositionCam

The function block XFC_PositionCam realizes a position cam that switches a digital output on or off, depending on the position.

In contrast to the digital cam controller MC_DigitalCamSwitch, the function block switches precisely one cam on a digital output track. This facilitates parameterization of the function block, although it cannot be used if several cams are required on an output track.

In addition to the switching state of the digital output the output data structure contains precise time information for the next switching operations. This information is used for the actual output at an XFC output terminal with a downstream function block (XFC_EL2252_V2 or XFC_EL2262).

Inputs

VAR_INPUT
    FirstOnPosition : LREAL;
    LastOnPosition  : LREAL;
    Modulo          : BOOL;
    ModuloFactor    : LREAL := 360;
    OnCompensation  : LREAL; 
    OffCompensation : LREAL;
    Options         : ST_CamSwitchOptions;
END_VAR

Name	Type	Description
FirstOnPosition	LREAL	First position from which the cam is switched on.
LastOnPosition	LREAL	Last position up to which the cam is switched on. The cam function is inverted, if LastOnPosition < FirstOnPosition
Modulo	BOOL	If Modulo TRUE, all positions are interpreted as modulo. The cam function is repeated cyclically. The parameter ModuloFactor is used for calculating the modulo cycle.
ModuloFactor	LREAL	ModuloFactor indicates the length of a modulo cycle in the positioning unit of the axis and is only used if Modulo TRUE.
OnCompensation	LREAL	Compensation time for the rising edge of the cam in [s]. For negative values of OnCompensation the switching time is brought forward, otherwise it is delayed. The value OnCompensation parameterized here has priority over TRACK_REF.
OffCompensation	LREAL	Compensation time for the falling edge of the cam in [s]. For negative values of OffCompensation the switching time is brought forward, otherwise it is delayed. The value OffCompensation parameterized here has priority over TRACK_REF.
Options	ST_CamSwitchOptions	Optional parameters

/ Inputs/Outputs

VAR_IN_OUT
    Output : OUTPUT_REF; 
    Axis   : AXIS_REF; 
END_VAR

Name	Type	Description
Output	OUTPUT_REF	The data structure Output contains the calculated state of the digital output and the associated timestamp for the output at a digital XFC output terminal
Axis	AXIS_REF	The axis data structure of type AXIS_REF addresses an axis unambiguously within the system. Among other parameters, it contains the current axis status, including position, velocity or error state.

Outputs

VAR_OUTPUT
    Error             : BOOL;
    ErrorID           : UDINT; 
END_VAR

Name	Type	Description
Error	BOOL	Becomes TRUE if an error occurs.
ErrorID	UDINT	Returns a error number when the error output is set.

Method of function of the time compensation