Siemens SINUMERIK 840D sl Function Manual page 528

Kinematic Transformation (M1)
TRANSMIT
Traverse into working area limitation
Any motion that leads into the working area limitation is rejected with alarm 21619. Any
corresponding part program block is not processed. The control system stops processing at
the end of the preceding block.
If the motion cannot be foreseen promptly enough (JOG modes, positioning axes), then the
control stops at the edge of the working area limitation.
Response close to working area limitation
If a tool center point traverses past the prohibited range, the control system automatically
reduces the feedrate and path acceleration rate such that the settings of the machine axes
(MD32000 $MA_MAX_AX_VELO[AX*] and MD32300 $MA_ MAX_AX_ACCEL[AX*]) are not
exceeded. The closer the path is to the working area limitation, the greater the reduction in
the feedrate may be.
7.2.8 Overlaid motions with TRANSMIT
The control system cannot predict overlaid motions. However, these do not interfere with the
function provided that they are very small (e.g. fine tool offset) in relation to the current
distance from the pole (or from working area limitation). With respect to axes that are
relevant for the transformation, the transformation monitors the overlaid motion and signals
any critical quantity by alarm 21618. This alarm indicates that the block-related velocity
planning function no longer adequately corresponds to the actual conditions on the machine.
When the alarm is output, the conventional, non-optimized online velocity monitor is
therefore activated. The preprocessing routine is re-synchronized with the main run by a
REORG generated internally in the control.
Alarm 21618 should be avoided whenever possible since it indicates a state that can lead to
axis overload and thus abortion of part program processing.
7.2.9 Monitoring of rotary axis rotations over 360º
Ambiguity of rotary axis positions
The positions of the rotary axis are ambiguous with respect to the number of rotations. The
control breaks down blocks containing several rotations around the pole into sub-blocks.
This subdivision must be noted with respect to parallel actions (e.g. output of auxiliary
functions, block-synchronized positioning axis motions) since the programmed block end is
no longer relevant for synchronization, but the end of the first sub-block. See:
References:
/FB1/ Function Manual, Basic Functions; "Auxiliary Functions to PLC" (H2)
/FB1/ Function Manual Basic Functions; "Synchronous Actions" (S5).
In single block operation the control system machines individual blocks explicitly. In other
modes, the sub-blocks are traversed with Look Ahead like a single block. A limitation of the
rotary axis setting range is monitored by the software limit switch monitoring function.
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Function Manual, 03/2009, 6FC5397-1BP10-4BA0
Extended Functions