Siemens SINUMERIK 840D sl Function Manual page 345

All four of the following programming lines have the same effect when the channel axis X is
imaged on the machine axis AX1, X1:
Z250 F100 FXS[AX1]=1 FXST[AX1]=12.3 FXSW[AX1]=2000
Z250 F100 FXS[X1]=1 FXST[X1]=12.3 FXSW[X1]=2000
Z250 F100 FXS[X]=1 FXST[X]=12.3 FXSW[X]=2000
Z250 F100 FXS[X]=1 FXST[X1]=12.3 FXSW[AX1]=2000
Functional sequence
The function is explained by the example below (sleeve is pressed onto workpiece).
Figure 2-1
Selection
The NC detects that the function "travel to fixed stop" is selected via the command
FXS[x]=1 and signals the PLC via the NST DB31, ... DBX62.4 ("Activate travel to fixed
stop") that the function has been selected.
If the machine data:
MD37060 FIXED_STOP_ACKN_MASK
(Monitoring of PLC acknowledgments for travel to fixed stop)
is set correspondingly, the acknowledgement of the PLC via the NST DB31 is, ... DBX3.1
("Enable travel to fixed stop") is waited for.
The programmed target position is then approached from the start position at the
programmed velocity. The fixed stop must be located between the start and target positions
of the axis/spindle. A programmed torque limit is effective from the start of the block, i.e. the
fixed stop is also approached with reduced torque. Allowance for this limitation is made in
the NC through an automatic reduction in the acceleration rate.
Basic logic functions: Travel to fixed stop (F1)
Function Manual, 11/2006, 6FC5397-0BP10-2BA0
Example of travel to fixed stop
Detailed Description
2.1 General functionality
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