Orientation Movements With Axis Limits - Siemens SINUMERIK 840DE sl Function Manual

3.9.2

Orientation movements with axis limits

Calculate rotary axis position
If the final orientation in a 5-axis transformation is programmed indirectly in an NC block by
means of a Euler, RPY angle or direction vector, it is necessary to calculate the rotary axis
positions that produce the desired orientation. This calculation has no unique result.
There are always at least two essentially different solutions. In addition, any number of
solutions can result from a modification to the rotary axis positions by any multiple of 360
degrees.
The control system chooses the solution which represents the shortest distance from the
current starting point, allowing for the programmed interpolation type.
Determining permissible axis limits
The control system attempts to define another permissible solution if the axis limits are violated,
by approaching the desired axis position along the shortest path. The second solution is then
verified, and if this solution also violates the axis limits, the axis positions for both solutions are
modified by multiples of 360 until a valid position is found.
The following conditions must be met in order to monitor the axis limits of a rotary axis and
modify the calculated end positions:
● A generic 5-axis transformation of type 24, 40 or 56 must be active.
● The axis must be referenced.
● The axis must not be a modulo rotary axis.
● The following machine data may not be equal to zero:
MD21180 $MC_ROT_AX_SWL_CHECK_MODE (check software limits for orientation axes)
MD21180 $MC_ROT_AX_SWL_CHECK_MODE specifies the conditions under which the
rotary axis positions may be modified:
Value Meaning
0
1
2
Switch-over to axis interpolation
If the axis positions have to be changed from the originally determined value, the system
switches to rotary axis interpolation because the original interpolation path, e.g. large circle
interpolation or conical interpolation, can no longer be maintained.
Example
An example for modifying the rotary axis motion of a 5-axis machine with a rotatable tool is
shown in Chapter "Example of generic 5-axis transformation (Page 243)".
Transformations
Function Manual, 06/2019, A5E47435470B AA
No modification permitted (default, equivalent to previous behavior).
Modification is only permitted if axis interpolation is active (ORIAXES or ORIMKS).
Modification is always permitted, even if vector interpolation (large circle interpolation, conical
interpolation, etc.) was active originally.
F2: Multi-axis transformations
3.9 Orientation
193