Siemens SINUMERIK 840D sl Function Manual page 329

Alarms are triggered when the various limitations are reached (alarms 16016, 16017, 16020,
16021). The control automatically prevents further movement in this direction. The traversing
keys and the handwheel have no effect in this direction.
Note
The software limit switches and working-area limitations are only active if the axis has first
been referenced.
If a work offset (DRF offset) via handwheel is active for axes, the software limit switches for
these axes are monitored during the main run in JOG mode. This means that the jerk
limitation has no effect when the software limit switches are approached. The velocity is
reduced at the software limit switch after the acceleration
(MD32300 $MA_MAX_AX_ACCEL (axis acceleration))
has been performed.
For further information on working-area limitations and hardware and software limit switches,
see:
References:
/FB1/ Function Manual, Axis Monitoring, Protection Zones (A3)
Retract axis
The axis can be retracted from a limit position by moving it in the opposite direction.
Note
Machine manufacturer
The function for retracting an axis that has approached the limit position depends on the
machine manufacturer. Please refer to the machine manufacturer's documentation!
Maximum velocity and acceleration
The velocity and acceleration used during manual travel are defined by the startup engineer
for specific axes using machine data. The control limits the values acting on the axes to the
maximum velocity and acceleration specifications.
References:
/FB1/ Function Manual Basic Machine; Velocities, Setpoint/Actual-Value Systems, Closed-
Loop Controls (G2)
/FB1/ Function Manual Basic Machine; Acceleration (B2)
Extended Functions
Function Manual, 09/2009, 6FC5397-1BP20-0BA0
H1: Manual travel and handwheel travel
4.9 Special features of manual travel
329