FC_ReadDriveEncoder

FC_ReadDriveEncoder - General Information

Overview

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

NOTE: The elements FB_WriteDriveEncoder und FC_ReadDriveEncoder are obsolete.

Use instead the elements FB_HomeAbs and FB_HomeSetPos with the mode PDL.ET_HomeSetPosMode.RestoreFromAxisEncoder.

Task

The position of the motor sensor should be read.

Description

The function reads the encoder position of the axis and reconstructs the position dependent on i_lrHomePos, i_lrAbsEncOffset, i_lrUserPeriod and the rotating direction of the axis. In doing so, the same parameter has to be used as when setting the position with the function block FB_WriteDriveEncoder. A SetPos is called up in the function.

The function must be called up once in the initialization part op the program for referencing the axes!

Interface

Input	Data type	Description
i_ifDrive	IF_Drive	Input for the axis that shall be controlled.
i_lrHomePos	LREAL	Value as when setting the position with the function block FB_WriteDriveEncoder.
i_lrAbsEncOffset	LREAL	Value as when setting the position with the function block FB_WriteDriveEncoder.
i_lrUserPeriod	LREAL	Value as when setting the position with the function block FB_WriteDriveEncoder.

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_sMsg	STRING[80]	Event-triggered message which gives more detailed information on the diagnostic state.

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_sMsg

STRING[80]

Event-triggered message which gives more detailed information on the diagnostic state.

Diagnostic Messages

q_etDiag	q_etDiagExt	Enumeration value	Description
OK	Ok	0	Ok
DriveConditionInvalid	DriveEncoderInvalid	175	The drive encoder is invalid.
InputParameterInvalid	AbsEncOffsetRange	178	AbsEncOffset is outside the valid range.
InputParameterInvalid	DriveInvalid	3	The connected drive is invalid.
InputParameterInvalid	UserPeriodRange	177	UserPeriod is outside the valid range.
UnexpectedProgramBehavior	UnexpectedFeedback	1	An unintended detected error occurred during execution.

AbsEncOffsetRange

Enumeration name:	AbsEncOffsetRange
Enumeration value:	178
Description:	AbsEncOffset is outside the valid range.

Issue	Cause	Solution
-	At the input i_lrAbsEncOffset, a number <= 0 or greater than the encoder period has been transferred.	For i_lrAbsEncOffset, the following must hold: 0 < i_lrAbsEncOffset < maximum possible value of Drive.EncoderPosition. For the valid value range for i_lrAbsEncOffset, see output q_sMsg of FC_ReadDriveEncoder

Issue

Cause

Solution

At the input i_lrAbsEncOffset, a number <= 0 or greater than the encoder period has been transferred.

For i_lrAbsEncOffset, the following must hold: 0 < i_lrAbsEncOffset < maximum possible value of Drive.EncoderPosition.

For the valid value range for i_lrAbsEncOffset, see output q_sMsg of FC_ReadDriveEncoder

DriveEncoderInvalid

Enumeration name:	DriveEncoderInvalid
Enumeration value:	175
Description:	The drive encoder is invalid.

Issue	Cause	Solution
-	The axis encoder is not supported.	Use an axis with a different encoder.

DriveInvalid

Enumeration name:	DriveInvalid
Enumeration value:	3
Description:	The connected drive is invalid.

Issue	Cause	Solution
-	At the input i_ifDrive, no drive was applied.	At the input i_ifDrive, a valid drive must be transferred.
-	The connected drive does not support all required functionalities.	Establish which functionalities are not supported by the drive by means of output q_sMsg. Use a drive which supports all required functionalities.

Issue

Cause

Solution

At the input i_ifDrive, no drive was applied.

At the input i_ifDrive, a valid drive must be transferred.

The connected drive does not support all required functionalities.

Establish which functionalities are not supported by the drive by means of output q_sMsg.

Use a drive which supports all required functionalities.

Enumeration name:	Ok
Enumeration value:	0
Description:	Ok

The position has been read successfully.

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.

UserPeriodRange

Enumeration name:	UserPeriodRange
Enumeration value:	177
Description:	UserPeriod is outside the valid range.

Issue	Cause	Solution
-	The input i_lrUserPeriod is negative.	For the input i_lrUserPeriod, a positive value or zero must be specified.
-	The input i_lrUserPeriod does not fit into the encoder period.	Assign the i_lrUserPeriod with zero to not consider any offset. The input i_lrUserPeriod must be chosen such that the following formula is fulfilled: ABS(lrEncoderPeriode/i_lrUserPeriod - TRUNC_INT(lrEncoderPeriode / i_lrUserPeriod)) = 0 with lrEncoderPeriode := EncoderRange * FeedConstant * DINT_TO_LREAL(GearIn) / DINT_TO_LREAL(GearOut) EncoderRange, FeedConstant, GearIn and GearOut are parameters of the i_ifDrive axis.

Issue

Cause

Solution

The input i_lrUserPeriod is negative.

For the input i_lrUserPeriod, a positive value or zero must be specified.

The input i_lrUserPeriod does not fit into the encoder period.

Assign the i_lrUserPeriod with zero to not consider any offset.

The input i_lrUserPeriod must be chosen such that the following formula is fulfilled:

ABS(lrEncoderPeriode/i_lrUserPeriod - TRUNC_INT(lrEncoderPeriode / i_lrUserPeriod)) = 0

with

lrEncoderPeriode := EncoderRange * FeedConstant * DINT_TO_LREAL(GearIn) / DINT_TO_LREAL(GearOut)

EncoderRange, FeedConstant, GearIn and GearOut are parameters of the i_ifDrive axis.