Siemens sinumerik 840D sl Function Manual page 445

Detailed description
2.1 Characteristics of tangential follow-up control
Response on follow-up
A difference must made between the following cases:
• Without intermediate block (TLIFT)
• With intermediate block (TLIFT), rounding off without G641
Special cases
• G641 rounding is possible between two blocks, both of which move at least one of the
• G641 rounding is possible between two blocks, both of which do not move either of the
In both cases, an intermediate block for the tangentially following axis is not created. An
intermediate block is not required because in the preprocessing run the rounded contour is
detected and the limit values for the following axis are calculated.
• Hidden corner in area
8
The path velocity of the leading axes is reduced to such an extent that the following axis
reaches its target position synchronously with the other axes.
The intermediate block generates the required turn of the tangentially following axis. It is
interpolated in such a way that the following axis travels at its limit velocity. The
intermediate block is not rounded. At the beginning of the intermediate block, the path
velocity of the leading axes is zero.
two leading axes of the tangentially following axis.
leading axes of the tangentially following axis.
A corner relevant for the tangential follow-up control can be hidden in space. (The
projection of the contour on the plane defined by the two leading axes is relevant).
If there is a hidden corner in space, an intermediate block is inserted before the block
(here N6) causing the tangential jump. This intermediate block moves the following axis to
the new position. The block transition is not rounded.
N1 TANG (C, X, Y, 1)
N2 TLIFT (C)
N3 G1 G641 X0 Y0 F1000
N4 TANGON (C)
N5 X10
N6 Y10 ; before working off this block, the rotary axis is repositioned.
N7 M3001.97
Special functions: Tangential Control (T3)
Function Manual, 11/2006, 6FC5397-2BP10-2BA0