Siemens SINUMERIK 840D sl Function Manual page 529

7.2.10 Constraints
Look Ahead
All functions requiring Look Ahead (traversal through pole, Look Ahead) work satisfactorily
only if the relevant axis motions can be calculated exactly in advance. With TRANSMIT, this
applies to the rotary axis and the linear axis perpendicular to it. If one of these axes is the
positioning axis, then the Look Ahead function is deactivated by alarm 10912 and the
conventional online velocity check activated instead.
Selection of method
The user is responsible for making the optimum choice of "Traversal through pole" or
"Rotation around pole".
Several pole traversals
A block can traverse the pole any number of times (e.g. programming of a helix with several
turns). The part program block is subdivided into a corresponding number of sub-blocks.
Analogously, blocks which rotate several times around the pole are likewise divided into sub-
blocks.
Rotary axis as modulo axis
The rotary axis can be a modulo rotary axis. However, this is not a mandatory requirement
as was the case in SW 2 and 3. The relevant restrictions applying in SW 2 and 3 have been
eliminated in SW 4.
Rotary axis as spindle
If the rotary axis without transformation is used as a spindle, it must be switched to position-
controlled mode with SPOS before the transformation is selected.
TRANSMIT with supplementary linear axis
With active TRANSMIT, the channel identifier of posBCS[ax[3]] must have another name in
the part program, like the geometry axes. If posBCS[ax[3]] is written only outside the
TRANSMIT transformation, this restriction does not apply if the axis has been assigned to a
geometry axis. With active TRANSMIT, no contour information is processed via ax[3].
REPOS
It is possible to reposition on the sub-blocks produced as a result of the extended TRANSMIT
function in SW 4. In this case, the control uses the first sub-block that is closest to the
repositioning point in the BCS.
Block search
In the case of block search with calculation, the block end point (of the last sub-block) is
approached in cases where intermediate blocks have been generated as the result of the
extended functionality in SW 4.
Extended Functions
Function Manual, 03/2009, 6FC5397-1BP10-4BA0
Kinematic Transformation (M1)
TRANSMIT
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