Siemens SINUMERIK 840D Function Manual page 456

M3: Coupled axes
14.3 Master value coupling
Reaction to Stop
All leading value coupled following axes react to channel stop and MODE GROUP stop.
Master value coupled following axes react to a stop due to end of program (M30, M02) if they
have not been activated by static synchronized actions (IDS=...). The following machine data
is to be observed in this connection:
MD20110 $MC_RESET_MODE_MASK (definition of initial control settings after RESET / TP
End)
MD20112 $MC_START_MODE_MASK (definition of initial control settings for NC-START)
Leading axis and following axis must always interpolate in the same channel. A following axis
located in a different channel cannot be coupled (axis replacement).
START and mode change enable a following axis in the master value coupling that has been
stopped.
RESET also enables a stopped following axis in master value coupling. If enabling by RESET
is not desired, or if it is dangerous (e.g. because the following axis is coupled to an external
master value not controlled by the NC), then MD20110 must be programmed such that master
value couplings are switched off with RESET (=2001H, i.e. bit 13 set to 1).
Axial functions
Actual value coupling causes a position offset between the leading and following axis. The
cause of this is the IPO cycle-based dead time in the position controller, which lies between the
actual value of the leading axis and the following axis.
Normally, the position offset and the following error is compensated by a linear extrapolation of
the master value to the extent of this dead time, i.e. dead time compensation is active in master
value coupling. The following MD setting is defined to deactivate the dead time compensation:
MD37160 $MA_LEAD_FUNCTION_MASK Bit 0 = 0
Interface to axis exchange
A master value coupled following axis receives its setpoint values from curve tables. Overlaid
programming of this axis is not possible in the part program. Therefore, the master value-
coupled following axis is removed from the channel in the same way as for axis exchange. This
is carried out automatically when the coupling is activated in the part program.
If the coupling is to be activated with synchronized action, then it must be prepared for it in
advance with RELEASE.
After a master value coupling has been deactivated, the former following axis can be
programmed again in the part program.
Spindles in master value coupling
A spindle can only be used as the master value coupled following axis if it has been switched
to axis mode beforehand. The machine data parameter block of the axis drive then applies.
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Axes and spindles
Function Manual, 06/2019, A5E47437747B AA