Siemens SINUMERIK 840D sl Programming Manual page 569

• POLFA(axis) must be a single axis at the time of triggering.
• POLFA(type) either type=1 or type=2.
The activate signals must be set for the retraction movement and remain set.
• The retracting movement configured with LFPOS, POLF for the axes selected with
• The extended retraction (i.e. LIFTFAST/LFPOS initiated through $AC_ESR_TRIGGER)
The maximum time available for retraction is the sum of the times MD 21380:
ESR_DELAY_TIME1 and MD 21381: ESR_DELAY_TIME2. When this time has expired,
rapid deceleration with follow-up is also initiated for the retraction axis.
Direction of withdrawal during rapid lifting and axis replacement
The frame valid at the time when the lift fast is activated is taken into consideration.
Note
Frames with rotation also affect the direction of lift via POLF. The NC-controlled retraction is
• configured: via MD 37500: 21 and 2 times specified via MD see above;
• enabled ($AA_ESR_ENABLE) and
• started: System variable $AC_ESR_TRIGGER with $AA_ESR_TRIGGER for single axes.
During NC-controlled retraction, LIFTFAST/LFPOS is used as with thread cutting, and the
retraction axis configured in the channel is enabled for rapid lifting using system variable
$AC_ESR_TRIGGER. Retraction initiated via $AC_ESR_TRIGGER is locked to prevent
multiple retractions.
Retraction axes must always be assigned to exactly one NC channel and may not be
switched among the channels. Attempts to change a retraction axis to another channel will
be indicated by alarm 26122.
Only once this axis has been deactivated again using $AA_ESR_ENABLE[AX] = 0, can it
be changed in a new channel. Once the axis has been changed, axes can be acted upon
again with $AA_ESR_ENABLE[AX] = 1.
Neutral axes cannot undertake NC-controlled ESR.
When $AA_ESR_ENABLE[AX] = 1 and when the axis is changed in neutral, the
suppressible ShowAlarm 26121 is triggered.
Job planning
Programming Manual, 03/2006 Edition, 6FC5398-2BP10-1BA0
POLFMASK or POLFMLIN replaces the path motion defined for these axes in the parts
program.
cannot be interrupted and can only be terminated prematurely via an
EMERGENCY STOP.
Additional functions
13.7 Extended stop and retract
13-37