Siemens SINUMERIK 840DE sl Function Manual page 225

The rotation vector is always perpendicular to the actual tool orientation and forms the angle
THETA in conjunction with the basic rotation vector.
Note
When configuring the machine, the direction in space in which the rotation vector points at a
specific angle of rotation can be defined, when the tool is in the basic orientation.
Formula
In general, the angle of rotation is interpolated with a 5th degree polynomial:
θu=θ
For parameter interval 0 ... 1, this produces the following values for linear coefficients:
d =θ
1
Interpolation of the rotation vector
The programmed rotation vector can be interpolated in the following way, using modal G
commands:
● ORIROTA (orientation rotation absolute):
The angle of rotation THETA is interpreted with reference to an absolute direction in space.
The basic direction of rotation is defined by machine data.
● ORIROTR (orientation rotation relative):
Angle of rotation THETA is interpreted relative to the plane defined by the start and end
orientation.
● ORIROTT (orientation rotation tangential):
Angle of rotation THETA is interpreted relative to the change in orientation. This means the
rotation vector interpolation is tangential to the change in orientation for THETA=0.
This is only different to ORIROTR, if the change in orientation does not take place in one
plane. This is the case if, for the orientation, at least one polynomial was programmed for "tilt
angle" PSI. An additionally programmed angle of rotation THETA can then be used to
interpolate the rotation vector such that it always forms a specific angle referred to the
change in orientation.
Activating rotation
A rotation of the orientation vector is programmed with identifier THETA. The following
programming options are available:
THETA=<value>:
THETA =
THETA = AC(...)
Transformations
Function Manual, 06/2019, A5E47435470B AA
+d u+d u +d u +d u +d
2 3 4
s 1 2 3 4
−θ −d −d −d −d
e s 2 3 4 5
Programming an angle of rotation that is reached at the end of the
block.
q
Programmed angle
e
active) - as well as also relative angle (G91 is active incremental
dimension).
Non-modal switchover to absolute dimensions
u
5
5
q
can be interpreted as absolute angle (G90 is
e
F2: Multi-axis transformations
3.11 Orientation vectors
(14)
(15)
225