Siemens SINUMERIK 840D Function Manual page 265

The appropriate synchronous axes traverse in synchronism with the leading axis. Interface
signal "Referenced/synchronized" of the leading axis is output to indicate that the reference
point has been reached.
Section 2:
Referencing of the synchronous axes
As soon as the leading axis has approached its reference point, the synchronous axis is
automatically referenced (as for reference point approach).
Further information:
R1: Referencing (Page 291)
The dependency between the leading axis and synchronous axis is inverted in the control for
this phase so that the leading axis now traverses in synchronism with the synchronous axis. IS
"Referenced/synchronized" of the synchronous axis is output to indicate that the reference
point has been reached. The gantry axis dependency then reverts to its previous status. If a
further synchronous axis is defined in the grouping, then this is also referenced in the way
described above.
Section 3:
Gantry synchronization process
Once all axes in the gantry grouping have been referenced, they must be synchronized with the
defined reference position. The actual position of each gantry axis is first compared to the
defined reference position of the leading axis.
Axes and spindles
Function Manual, 06/2019, A5E47437747B AA
9.3 Referencing and synchronization of gantry axes
G1: Gantry axes
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