Siemens Sinumerik 840D sl Programming Manual page 362

Supplementary commands
15.6 Travel to fixed stop (FXS, FXST, FXSW)
Note
The commands FXS, FXST and FXSW are modal.
The programming of FXST and FXSW is optional: If no parameter is specified, the last
programmed value or the value set in the relevant machine data applies.
Activate travel to fixed stop: FXS[<axis>] = 1
The movement to the destination point can be described as a path or positioning axis
movement. With positioning axes, the function can be performed across block boundaries.
Travel to fixed stop can be performed simultaneously for several axes and parallel to the
movement of other axes. The fixed stop must be located between the start and end positions.
NOTICE
Risk of collision
It is not permissible to program a new position for an axis if the "Travel to fixed stop" function
has already been activated for an axis/spindle.
Spindles must be switched to position-controlled mode before the function is selected.
Example:
Program code
X250 Y100 F100 FXS[X1]=1 FXST[X1]=12.3 FXSW[X1]=2
...
Deactivate travel to fixed stop: FXS[<axis>] = 0
Deselection of the function triggers a preprocessing stop.
362
Comment
; Axis X1 travels with feedrate
F100 (specification optional)
to target position X=250 mm.
The clamping torque is 12.3% of
the maximum drive torque, moni-
toring is performed in a 2 mm
wide window.
Programming Manual, 01/2015, 6FC5398-1BP40-5BA2
Fundamentals