Siemens SINUMERIK 840Di sl Programming Manual page 191

The "Travel to fixed stop" commands can be called from synchronized actions/technology
cycles. They can be activated without initiation of a motion, the torque is limited
instantaneously. As soon as the axis is moved via a setpoint, the limit stop monitor is
activated.
Rise ramp
A rise ramp for the new torque limit can be defined by machine data to prevent any abrupt
changes to the torque limit setting (e.g., insertion of a quill).
Link and container axes
Travel to fixed stop is also permitted for
• Link axes
• Container axes
The status of the assigned machine axis is unaffected by container switches.
References: /FB2/Function Manual Extended Functions; Multiple Operator Panels and
NCUs. (B3)
This also applies to modal torque limiting with FOCON (see "travel with limited
torque/force").
Activation from synchronized actions
Example:
If the anticipated event ($R1) occurs and travel to fixed stop is not already operative, then
FXS must be activated for axis Y. The torque must correspond to 10% of the rated torque
value. The width of the monitoring window is set to the default.
N10 IDS=1 WHENEVER (($R1=1) AND ($AA_FXS[Y]==0)) DO $R1=0 FXS[Y]=1
FXST[Y]=10
The normal parts program must ensure that $R1 is set at the desired point in time.
Deactivation from synchronized actions
Example:
If an anticipated event ($R3) has occurred and the status "Limit stop contacted" (system
variable $AA_FXS) is reached, then FXS must be deselected.
N13 IDS=4 WHENEVER (($R3==1) AND ($AA_FXS[Y]==1)) DO FXS[Y]=0 FA[Y]=1000
POS[Y]=0
Fixed stop reached
When the fixed stop has been reached:
• The distance-to-go is deleted and the position setpoint is manipulated,
• The drive torque increases to the programmed limit value FXSW and then remains
• Fixed stop monitoring is activated within the specified window width.
Fundamentals
Programming Manual, 11/2006, 6FC5398-1BP10-2BA0
constant,
4.21 Travel to fixed stop (FXS, FXST, FXSW)
Motion commands
191