Siemens SINUMERIK 840D sl Function Manual page 463

traversing through the singularity (speed planning in preprocessing) or an overload of the axis
if no speed planning is carried out in preprocessing.
Note
Cartesian PTP travel is only permissible in conjunction with the interpolation types G0 and G1.
Versions
Three versions are available for Cartesian PTP travel:
● PTP
The programmed Cartesian position in G0 and G1 blocks is approached with synchronous
axis motion.
● PTPG0
Only in G0 blocks is the programmed Cartesian position approached with synchronous axis
motion. In G1 blocks, it is switched to the type of motion CP (CP = Continuous Path) and
the position is approached with a Cartesian path motion.
● PTPWOC (only for orientation transformation)
Just the same as PTP, however, without any compensatory motion, which is caused by
motion of rotary axes and orientation axes.
Since the transformation, which compensates the movement of the tool tip (TCP) during
orientation changes, is not active, the position of the TCP in the workpiece coordinate
system must generally also be changed if no linear axes involved in the transformation are
programmed.
Programmed linear axis movements are carried out in the workpiece coordinate system
that applies at the beginning of the block and overlays the simultaneously programmed
rotary axis movements if applicable. The block end point that is reached in the workpiece
coordinate system is therefore generally not the same as the programmed end point.
NOTICE
Risk of collision
For PTP travel it must be observed that in part there are significantly different tool movements
than with CP!
This must especially be considered for PTPG0, because subprograms can be created with
it independently of the active transformation. With active front-end transformation
(TRANSMIT), however, entirely different collision risks may occur than with an orientation
transformation (TRAORI).
For PTP travel with active front-end transformation (TRANSMIT), machine axes basically
travel the shortest path. Minor displacements of the block end point can cause the rotary axis
to rotate by +179.99° instead of + -179.99°. This results in a completely different motion, even
though the block end point has hardly changed.
Extended Functions
Function Manual, 10/2015, 6FC5397-1BP40-5BA3
M1: Kinematic transformation
7.6 Cartesian PTP travel
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