SMC_BacklashCompensation (FB)

FUNCTION_BLOCK SMC_BacklashCompensation

This function block can be used to compensate the backlash which arises for example at a belt drive or in a gear-box.

For this purpose a (usually virtual) master axis gets mirrored on the real slave axis, whose backlash should be compensated. The function block works similar to a phasing function block, the phase depends on the direction of the master axis. If the master axis starts in a certain direction, the slave axis does the same plus an additional movement (distance: fBacklash) in this direction; if the master axis inverts, the slave axis also turns around and additionally covers the double distance fBacklash in this new direction.

Take care that the master axis and the slave axis are at the same position when the module starts working, because otherwise the slave axis would be positioned on the master axis.

InOut:

Scope	Name	Type	Initial	Comment
Inout	Master	AXIS_REF_SM3		Reference to master axis
Inout	Slave	AXIS_REF_SM3		Reference to slave axis
Input	bExecute	BOOL		Rising edge: Starts the execution of the function block. It stays active until the slave axis gets interrupted by another movement, or if an error occurs.
	fBacklash	LREAL		Distance/Backlash to be compensated.
	fCompensationVel	LREAL		Additional velocity, which should be used for the compensation.
	fCompensationAcc	LREAL		Additional acceleration, which should be used for the compensation.
	fCompensationDec	LREAL		Additional deceleration, which should be used for the compensation.
	fCompensationJerk	LREAL		Additional jerk, which should be used for the compensation.
	eBacklashMode	SMC_BACKLASH_MODE	SMC_BL_AUTO	The mode of backlash compensation. SMC_BL_AUTO : Direction in which the master axis moves; determines the compensation direction. SMC_BL_POSITIVE : Compensation in positive direction, independent on the movement of the master axis. SMC_BL_NEGATIVE : Compensation in negative direction, independent on the movement of the master axis. SMC_BL_OFF : No compensation
	eBacklashStartState	SMC_BACKLASH_STARTSTATE	SMC_BL_START_NONE	The start condition of the axis. SMC_BL_START_NEGATIVE : The slave axis is under traction in negative direction, that is: a movement in negative direction needs no compensation; in case of a movement in positive direction the double fBacklash-distance will be made up. SMC_BL_START_POSITIVE : The slave axis is under traction in positive direction, that is: a movement in positive direction needs no compensation; in case of a movement in negative direction the double fBacklash-distance will be made up. SMC_BL_START_NONE : The slave axis is not under traction; a movement in positive or negative direction will cause a corresponding compensating movement of distance fBacklash.
Output	bBusy	BOOL		TRUE: Execution of the function block is not finished yet.
	bCommandAborted	BOOL		TRUE: Command has been aborted by another command.
	bError	BOOL		TRUE: Error has occured within the function block.
	iErrorID	SMC_ERROR		Error identification
	bCompensating	BOOL		TRUE: While compensating a backlash.