Siemens SINUMERIK 840D Function Manual page 251

Synchronized actions
● Stop (MOV=0)
If an indexing axis is stopped with a synchronized action using MOV=0, then the axis stops
in the traversing direction at the next possible indexing position
● Delete distance to go (DELDTG)
If, for an indexing axis, the distance to go is deleted with a synchronized action
using DELDTG, then the axis is immediately stopped without stopping at an indexing position
Further information: Function Manual Synchronized Actions
Frames and work offsets
In conjunction with indexing axes, generally frames are not necessary. As a consequence, we
recommend that frames and work offsets for indexing axes are suppressed in NC programs.
Software limit switch
When manually traversing an indexing axis in the JOG or JOG/INC operating mode, the
indexing axis traverses – as a maximum up – to the last indexing position before the software
limit switch.
Manual traversing using a handwheel (DRF)
When traversing an indexing axis using the handwheel, the indexing positions are not taken
into account. This means that the indexing axis stops immediately, also between two indexing
positions, with the end of the handwheel pulse.
"Hirth axes"
In addition to the secondary conditions mentioned above, for "Hirth axes" the following
additional secondary conditions must be observed.
Various channel and axis-specific NC/PLC interface signals
If, while a "Hirth axis" is being traversed, at least one of the following signals occurs, then the
axis stops immediately at the next possible indexing position in the traversing direction.
● Channel-specific signals
– DB21, ... DBB4 == 0 (feedrate override)
– DB21, ... DBX6.2 == 1 (delete distance-to-go)
– DB21, ... DBX7.3 == 1 (NC Stop)
– DB21, ... DBX7.4 == 1 (NC Stop axes plus spindles)
– DB21, ... DBX7.7 == 1 (reset)
● Axisspecific signals
– DB31, ... DBX4.3 == 1 (feedrate stop)
Emergency Stop
If, while a "Hirth axis" is being traversed, an Emergency Stop is initiated then the axis is
immediately stopped:
DB10 DBX56.1 == 1 (Emergency Stop)
Axes and spindles
Function Manual, 06/2019, A5E47437747B AA
T1: Indexing axes
8.5 Supplementary conditions
251