Lenze PLC Designer PLC-Designer (R2-x) SoftMotion - Manual (Page 221)

DMS 5.2 EN 03/2011 TD17
L
221
L-force | PLC Designer - SoftMotion
The SM_Trafo.lib library
Transformation function blocks
9.1.1.5 GantryCutter
The SMC_TRAFO<n>_Gantry<n> program organisation units also exist as
SMC_TRAFO<n>_GantryCutter<n>. These POUs contain transformations for gantry
systems with one rotating axis that is controlled in such a way that it points along the
current path tangent. They contain the rotating axis (DriveR), which must be created as a
rotary axis with period 360, an offset (dOffsetX) and the direction of rotation (iDirectionR)
as additional inputs. The reverse transformation POU also requires the vector of the
current path tangent (v), which is an output of the interpolator.
9.1.1.6 SMC_TRAFOV_Gantry
Some of the reverse transformations described above are available in a version whereby
the path velocity and direction are also used as control variables for the axes. These start
"SMC_TRAFOV_" instead of "SMC_TRAFO_" and they need the path tangent (v) and
velocity (dVel) from the interpolator as additional inputs. They show the target velocities
(dvx/dvy/dvz) as well as the set positions. The advantage of this method is that the
following error in the drive can be minimised by means of velocity feedforward control,
provided that the drive supports this mode. Each axis should, therefore, be controlled by
means of the SMC_ControlAxisByPosVel program organisation unit.