Siemens sinumerik 840D sl Function Manual page 356

Detailed description
2.7 Extended stop and retract (ESR)
The extended retraction (i.e. LIFTFAST/LFPOS initiated through $AC_ESR_TRIGGER )
cannot be interrupted and can only be terminated prematurely via an EMERGENCY STOP.
Speed and acceleration limits for the axes involved in the retraction are monitored during the
retraction motion. The retracting movement takes place with BRISK, i.e. without jerk
limitation.
The maximum time available for retraction is the sum of the times in the following machine
data:
MD21380 $MC_ESR_DELAY_TIME1
and
MD21381 $MC_ESR_DELAY_TIME2
When this time has expired, rapid deceleration with follow-up is also initiated for the
retraction axis.
Boundary conditions
Lift fast is
• (due to axis replacement, individual axis state or similar) are not controlled by the channel
• are in speed-controlled mode (spindles)
• are interpolated as positioning spindles (SPOS/SPOSA).
Modulo rotary axes respond to lift fast as follows:
• For incremental programming of the target position, the latter is approached without
• With absolute programming, the target position is approached time-optimized with the
The retraction movement is interpolated linearly, using the maximum acceleration and speed
of the axes involved in POLFLIN.
Only one linear retraction is permitted in each channel. This means that multiple axis groups,
which approach their retraction positions linearly, cannot be created in the channel.
In parallel with linear retraction, additional axes can also use POLFMASK for independent
axial retraction movement to their programmed retraction positions.
If axes are used in both POLFMASK and in POLFMIN, it should be noted that the last state
programmed is always active for retracting movement. This means that an axis previously
activated with POLFMIN is removed from the linear relation following programming in
POLFMASK and the retracting movement would then take place as an independent
movement (see the examples in Chapter "Fast Retraction in Linear Relation of the Axes").
The parameters valid at triggering time are decisive for the retraction movement. If one of
these parameters (POLF, POLFMASK, POLFMLIN, Frame, etc.) changes during the
retracting movement (e.g. due to a block change), this change does not affect the retraction
movement that has already started.
136
not
processed for the following axes:
modulo offset.
use of modulo offsets. This is almost identical to positioning via the shortest path.
Special functions: Axis Couplings and ESR (M3)
Function Manual, 11/2006, 6FC5397-2BP10-2BA0