Siemens SINUMERIK 828D Function Manual page 155

Implicit exact stop
In some cases, an exact stop needs to be generated in continuous­path 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 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.
References:
For more information about BRISK and SOFT, refer to the chapter "Acceleration (B2)".
• If the "empty buffer" function is programmed, the previous block is terminated when the selected exact-stop
criterion is reached.
Velocity = 0 in continuous­path 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, 09/2011, 6FC5397-0BP40-2BA0
B1: Continuous­path Mode, Exact Stop, LookAhead
3.3 Continuous-path mode
155