Relative positioning in StartPositionBased operating mode

The following application example illustrates how, in "StartPositionBased" operating mode, you can use the user interface for relative positioning of an axis.

A change to lrDistance is applied. The new target position results from the start position plus lrDistance. A change to lrDistance is applied as long as xStart is present.

Control

Control the axis in the PositioningRelative structure as follows:

• To activate the operating mode, set xActivate to "TRUE".
• Define the setpoints for lrDistance, lrVelocity, lrAcceleration, lrDeceleration, and lrJerk.
• Set eMode to StartPositionBased in the CONFIG structure.
• To start the operating mode, set xStart to "TRUE".

Interface in the IEC Editor

Trace recording

[1]	SEW_GVL.Interface_Axis1.ProfileGeneration.PositioningRelative.In.xActivate
[2]	SEW_GVL.Interface_Axis1.ProfileGeneration.PositioningRelative.In.xStart
[3]	SEW_GVL.Interface_Axis1.ProfileGeneration.PositioningRelative.In.lrDistance
[4]	SEW_GVL_Internal.Axis1._fbProfileGenerationControl._stOUTInterpolation.stSetpointsUserUnits.lrPosition
[5]	SEW_GVL_Internal.Axis1._fbProfileGenerationControl._stOUTInterpolation.stSetpointsUserUnits.lrVelocity
[6]	SEW_GVL_Internal.Axis1._fbProfileGenerationControl._stOUTInterpolation.stSetpointsUserUnits.lrAcceleration
[7]	SEW_GVL.Interface_Axis1.ProfileGeneration.PositioningRelative.Out.xInPosition
[8]	SEW_GVL.Interface_Axis1.ProfileGeneration.PositioningRelative.Out.xStopped

Note:

During ongoing movement, lrDistance is changed from 200.0 to 400.0. The change is in relation to the start position; the movement stops at 400.0.