Siemens SINUMERIK 840D sl Function Manual page 463

The extended retraction (i.e. LIFTFAST/LFPOS initiated through $AC_ESR_TRIGGER )
cannot be interrupted and can only be terminated prematurely using EMERGENCY OFF.
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 following delay times:
● MD21380 $MC_ESR_DELAY_TIME1 (delay time, ESR axes)
● MD21381 $MC_ESR_DELAY_TIME2 (delay time, ESR axes)
After the delay time has expired, fast braking is also initiated for the retraction axis with
subsequent tracking.
Boundary conditions
Retraction and/or rapid lift is not executed for the following axes:
● Axes, which are not permanently assigned a channel
● Axes, which are in the open-loop speed-controlled mode (spindles)
● Axes, which are interpolated as positioning spindles (SPOS/SPOSA)
Modulo rotary axes respond to rapid lift as follows:
● For incremental programming of the target position, the latter is approached without modulo
offset.
● With absolute programming, the target position is approached time-optimized with the use
of modulo offsets. This is almost identical to positioning via the shortest path.
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 relationship following programming in
POLFMASK and the retracting movement would then take place as an independent movement
(see the examples in Chapter "Lift fast with linear relation of axes (Page 493)").
The parameters valid at the 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.
Supplementary conditions, path axes
If, for a path axis ESR_REACTION=21 (NC-controlled retraction) is configured and enabled
with $AC_ESR_ENABLE=1, then ESR_REACTION=22 (extended stopping) is active for all
path axes for which no ESR_REACTION=21 is configured or enabled.
Special functions
Function Manual, 01/2015, 6FC5397-2BP40-5BA2
R3: Extended stop and retract
9.2 Control-managed ESR - 840D sl only
463