Siemens SINUMERIK 840D sl Function Manual page 185

Implicit exact stop
In some cases, an exact stop needs to be generated in continuous-path mode to allow the
execution of subsequent actions. In such situations, the path velocity is reduced to zero.
● If auxiliary functions are output before the traverse motion, the previous block is only
terminated when the selected exact-stop criterion is fulfilled.
● If auxiliary functions are to be output after the traverse motion, they are output after the
interpolator end of the block.
● If an executable block (e.g. starting of a positioning axis) contains no travel information for
the path axes, the previous block is terminated on reaching the selected exact-stop criterion.
● If a positioning axis is declared to be the geometry axis, the previous block is terminated
at the interpolator end when the geometry axis is programmed.
● If a synchronized axis is programmed that was last programmed as a positioning axis or
spindle (initial setting of the special axis is positioning axis), the previous block is ended at
the interpolator end.
● If the transformation is changed, the block previously processed is terminated with the
active exact-stop criterion.
● A block is terminated on interpolator end if the following block contains the changeover of
the acceleration profile BRISK/SOFT (see Section "B2: Acceleration (Page 243)").
● If the "empty buffer" function is programmed, the previous block is terminated when the
selected exact-stop criterion is reached.
Velocity = 0 in continuous-path mode
Regardless of the implicit exact stop response, the path motion is braked down to zero velocity
at the end of the block in cases where:
● Positioning axes are programmed with the instruction POS, and their traversing time
exceeds that of the path axes. The block change occurs when the "exact stop fine" of the
positioning axes is reached.
● The time taken to position a spindle programmed with the instruction SPOS is longer than
the traversing time of the path axes. The block change is carried out when the "exact stop
fine" of the positioning spindle is reached.
● The current block contains traversing commands for geometry axes and the following block
traversing commands for synchronized axes or, alternatively, the current block contains
traversing commands for synchronized axes and the subsequent block traversing
commands for geometry axes.
● Synchronization is required.
Basic Functions
Function Manual, 01/2015, 6FC5397-0BP40-5BA2
B1: Continuous-path mode, Exact stop, Look Ahead
4.3 Continuous-path mode
185