Siemens SINUMERIK 840D sl Programming Manual page 610

Axis couplings
9.4 Electronic gear (EG)
Further information
Description of the switch-in versions
Version 1:
The positions of the leading axes and following axis at the instant the grouping is switched
on are stored as "Synchronized positions". The "Synchronized positions" can be read with
the system variable $AA_EG_SYN.
Version 2:
If modulo axes are contained in the coupling group, their position values are modulus-
reduced. This ensures that the next possible synchronized position is approached (so-called
relative synchronization
approached if "Enable following axis override" interface signal DB(30 + axis number), DBX
26 bit 4 is issued for the following axis. If it is not issued, the program stops at the
EGONSYN block and self-clearing alarm 16771 is output until the above mentioned signal is
set.
Version 3:
The tooth distance (deg.) is calculated like this: 360 * Zi/Ni. If the following axis is stopped at
the time of calling, path optimization returns responds identically to time optimization.
If the following axis is already in motion, NTGP will synchronize at the next tooth gap
irrespective of the current velocity of the following axis. If the following axis is already in
motion, NTGT will synchronize at the next tooth gap depending on the current velocity of the
following axis. The axis is also decelerated, if necessary.
Curve tables
If a curve table is used for one of the leading axes:
Ni
Zi
LAi
610
: e.g. the next tooth gap). The synchronized position is only
The denominator of the coupling factor for linear coupling must be set to 0.
(Denominator 0 would be illegal for linear couplings.) Nominator zero tells the
control that
is the number of the curve table to use. The curve table with the specified
number must already be defined at POWER ON.
The leading axis specified corresponds to the one specified for coupling via
coupling factor (linear coupling).
Programming Manual, 06/2009, 6FC5398-2BP20-0BA0
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