FC_ProfileInvCompute

FC_ProfileInvCompute - General Information

Overview

Type:	Function
Available as of:	V1.0.3.0
Versions:	Current version

Task

Determination of the master position of a cam to a slave position

Description

The function starts with a linear search from i_lrXStart with the step distance i_lrXIncr. If a sign reversal is detected in the difference of i_lrYPos – Y(Xi), the section containing the solution has been found.

A binary iterative procedure is then used in this section in order to find the result q_lrXPos.

The function is ended after either

|i_lrYpos – Y(XPos)| <= i_lrAccuracy or after a maximum of 20 passes.

Interface

Input	Data type	Description
i_diProfileId	DINT	Id of the underlying profile
i_lrYPos	LREAL	Slave position to which a master position is to be found.
i_lrXOffset	LREAL	Offset of the master encoder position
i_lrYOffset	LREAL	Offset of the slave axis position
i_lrXFactor	LREAL	Scaling factor of the master encoder
i_lrYFactor	LREAL	Scaling factor of the slave axis
i_lrXStart	LREAL	Start value for the search
i_lrXIncr	LREAL	Step distance for the search
i_lrAccuracy	LREAL	Accuracy of the result at which the iteration is to be canceled.

Output	Data type	Description
q_etDiag	GD.ET_Diag	General library-independent statement on the diagnostic. A value not equal to ET_Diag.Ok corresponds to an diagnostic message.
q_etDiagExt	ET_DiagExt	POU-specific output on the diagnostic. q_etDiag = ET_Diag.Ok -> Status message q_etDiag <> ET_Diag.Ok -> Diagnostic message
q_lrXPos	LREAL	Master encoder position relative to the slave axis position i_lrYPos

Output

Data type

Description

q_etDiag

GD.ET_Diag

General library-independent statement on the diagnostic.

A value not equal to ET_Diag.Ok corresponds to an diagnostic message.

q_etDiagExt

ET_DiagExt

POU-specific output on the diagnostic.

q_etDiag = ET_Diag.Ok -> Status message

q_etDiag <> ET_Diag.Ok -> Diagnostic message

q_lrXPos

LREAL

Master encoder position relative to the slave axis position i_lrYPos

Example

Cam with three X positions for one Y position

Example for finding multiple solutions:

lrXStart := lrXOffset;
i := 0;

WHILE lrXStart + lrXIncr < lrXOffset + lrXFactor DO

FC_ProfileInvCompute(i_diProfileId := diProfileId,
i_lrYPos := lrYPos,
i_lrXOffset := lrXOffset,
i_lrYOffset := lrYOffset,
i_lrXFactor := lrXFactor,
i_lrYFactor := lrYFactor,
i_lrXStart := lrXStart,
i_lrXIncr := lrXIncr,
i_lrAccuracy := lrAccuracy,
q_etDiag : etDiag,
q_etDiagExt : etDiagExt,
q_lrXPos := lrXPos);

IF etDiag <> Ok THEN
EXIT;
END_IF

alrXPos[i]:= lrXPos; (* save result *)
i := i + 1; (* number of valid results *)

lrXStart := lrXPos + lrXIncr / 2.0; (*Start of next search *)
END_WHILE

Diagnostic Messages

q_etDiag	q_etDiagExt	Enumeration value	Description
OK	Ok	0	Ok
ExecutionAborted	MaxNumberOfIterationsExceeded	96	The maximum number of iteration steps has been exceeded.
InputParameterInvalid	AccuracyRange	118	Accuracy is outside the valid range.
InputParameterInvalid	ProfileIdInvalid	114	The ProfileId is invalid.
InputParameterInvalid	XFactorRange	115	XFactor is outside the valid range.
InputParameterInvalid	XIncrRange	117	XIncr is outside the valid range.
InputParameterInvalid	XStartRange	119	XStart is outside the valid range.
InputParameterInvalid	YPosRange	120	YPos is outside the valid range.
UnexpectedProgramBehavior	ProfileAlreadyInUse	116	The profile is already in use.
UnexpectedProgramBehavior	UnexpectedFeedback	1	An unintended detected error occurred during execution.

AccuracyRange

Enumeration name:	AccuracyRange
Enumeration value:	118
Description:	Accuracy is outside the valid range.

Issue	Cause	Solution
-	At the input i_lrAccuracy, a number smaller than 1E-10 has been applied.	A value greater than zero has to be specified.

MaxNumberOfIterationsExceeded

Enumeration name:	MaxNumberOfIterationsExceeded
Enumeration value:	96
Description:	The maximum number of iteration steps has been exceeded.

Issue	Cause	Solution
-	i_lrAccuracy has been chosen too small. The numerical approximation method converges to such a result in not less than Gc_diMaxNumberOfIterations iteration steps.	A higher value must be chosen for i_lrAccuracy.

Enumeration name:	Ok
Enumeration value:	0
Description:	Ok

The master position has been determined successfully.

ProfileAlreadyInUse

Enumeration name:	ProfileAlreadyInUse
Enumeration value:	116
Description:	The profile is already in use.

Issue	Cause	Solution
-	The motion profile is already in use.	Verify the motion data.

ProfileIdInvalid

Enumeration name:	ProfileIdInvalid
Enumeration value:	114
Description:	The ProfileId is invalid.

Issue	Cause	Solution
-	The profile does not exist.	Verify the value at the input i_diProfileId.

UnexpectedFeedback

Enumeration name:	UnexpectedFeedback
Enumeration value:	1
Description:	An unintended detected error occurred during execution.

Issue	Cause	Solution
-	An error occurred in the internal execution.	Please inform the support team about this error.

XFactorRange

Enumeration name:	XFactorRange
Enumeration value:	115
Description:	XFactor is outside the valid range.

Issue	Cause	Solution
-	At the input i_lrXFactor, a value 0 has been applied.	i_lrXFactor must not be 0.

XIncrRange

Enumeration name:	XIncrRange
Enumeration value:	117
Description:	XIncr is outside the valid range.

Issue	Cause	Solution
-	At the input i_lrXIncr, a number <= 0 has been applied.	i_lrXIncr must be greater than 0.

XStartRange

Enumeration name:	XStartRange
Enumeration value:	119
Description:	XStart is outside the valid range.

Issue	Cause	Solution
-	At the input i_lrXStart, a number that lies outside of the cam has been applied.	Verify i_lrXStart and set it to a value exceeding i_lrXOffset. Verify i_lrXStart and set it to a value smaller than i_lrXOffset + i_lrXFactor - i_lrXIncr.

Issue

Cause

Solution

At the input i_lrXStart, a number that lies outside of the cam has been applied.

Verify i_lrXStart and set it to a value exceeding i_lrXOffset.

Verify i_lrXStart and set it to a value smaller than i_lrXOffset + i_lrXFactor - i_lrXIncr.

YPosRange

Enumeration name:	YPosRange
Enumeration value:	120
Description:	YPos is outside the valid range.

Issue	Cause	Solution
-	At the input i_lrYPos, a value has been applied which cannot be reached by the master in the specified section of the cam.	Verify the definition of the cam. Verify the start position i_lrXStart.

Issue

Cause

Solution

At the input i_lrYPos, a value has been applied which cannot be reached by the master in the specified section of the cam.

Verify the definition of the cam.

Verify the start position i_lrXStart.