Siemens SINUMERIK 840D sl Function Manual page 246

M3: Coupled axes
5.3 Master value coupling
Logging
The curve tables generated by the definition of motion sequences are stored in the battery-
backed memory.
The curve tables are not lost when the control system is switched off.
These functions have no effect on cyclic machines because they are performed without
operator actions. Nor does it make sense to perform automatic (re-)positioning via the NC
with external master values.
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Function Manual, 09/2011, 6FC5397-2BP40-2BA0
Special Functions