Siemens SINUMERIK 840D sl Function Manual page 800

Positioning Axes (P2)
Motion behavior and interpolation functions
● NCK switches the axis to the 'stopped' state and notifies the PLC of the status change via
● NCK ends this operation.
Alternatives
The following scenarios for stopping the axis/spindle are possible:
● Accept and stop the axis/spindle simultaneously.
● The axis/spindle is executing several operating sequences:
● PLC requests the NCK to stop the axis/spindle, an axial stop alarm for this axis is
● The PLC requests the NCK to stop the axis/spindle, a stop alarm is generated
● A retraction movement of "Extended stop and retract" cannot be stopped. This retraction
Marginal conditions
The PLC must already have accepted control of the axis/spindle. Else, the following NC/PLC
interface signal is ignored:
NST DB31, ... DBX28.6 (AxStop, stop)
800
the VDI interface (NCK→PLC) as follows with:
DB31, ... DBX63.2 (Axis stop active) == 0,
DB31, ... DBX64.7 ("Motion command plus") == 0 or
DB31, ... DBX64.6 ("Motion command minus") == 0 and
DB31, ... DBX60.7 (Exact stop fine) == 1 or
DB31, ... DBX60.6 (Exact stop coarse) == 1
Axis status interrupted with system variable $AA_SNGLAX_STAT == 3
If PLC notifies the NCK: PLC wants to accept the axis/spindle and it is simultaneously
detected that the axis/spindle is to be stopped, then: NCK flags the axis/spindle as
accepted and continues at the position where the interruption occurred.
Stop all operations except for movements resulting from following axis motions. Following
axis motion can only be stopped by stopping the leading axis!
generated simultaneously:
The NCK brakes the axis along a ramp and confirms the braking operation via the OPI.
At the same time the PLC alarm is sent with:
DB31, ... DBX61.1 ("Axial alarm") == 1 and
the status system variable $AA_SNGLAX_STAT == 5 is set.
The NCK switches the axis to the Stopped state and signals this status change to the
PLC.
simultaneously and the NC program is activated. The stop alarm is ignored and does not
take effect.
motion cannot be halted with a NST:
DB31, ... DBX28.6 (AxStop, Stop)
on the PLC interface.
Function Manual, 03/2009, 6FC5397-1BP10-4BA0
Extended Functions