Points To Note - Siemens SINUMERIK 840D sl Function Manual

G1: Gantry axes
2.3 Referencing and synchronization of gantry axes
If the gantry grouping is switched from follow-up mode to position control mode, axis
synchronism is automatically restored provided the actual-value monitor does not detect a
difference between the positions of the leading and synchronized axes greater than the
setting in the machine data:
MD36030 $MA_STANDSTILL_POS_TOL (standstill tolerance)
In this case, a new setpoint is specified for the synchronized axis (axes) without interpolation.
The positional difference detected earlier is then corrected by the position controller. The
correction causes only the synchronized axis (axes) to move.
The motional sequence of the synchronized axis (axes) is analogous to the situation in which
the grouping switches from the "Hold" state to position control mode. In this case, the position
specified by the position controller before the grouping is halted is set again on condition that
the zero speed monitor has not activated alarm 25040 (with follow-up as alarm reaction) in
the meantime.
The same tolerance window is used for this mode of automatic synchronization as for the
zero speed monitoring function:
MD36030 $MA_STANDSTILL_POS_TOL (standstill tolerance)
Parameter rate dependence loads with machine data:
MD36012 $MA_STOP_LIMIT_FACTOR (exact stop coarse/fine and standstill factor)
Note
The following interface signal blocks automatic synchronization in all modes except
referencing mode:
DB31, ... DBX29.5 (no automatic synchronization)
Should the automatic synchronization be activated at this point, then the following interface
signal must be reset:
DB31, ... DBX29.5 = 0 (no automatic synchronization)
Then switch one of the axes in the gantry grouping from follow-up mode to position-
controlled mode. This is achieved with the interface signals:
DB31, ... DBX1.4 = 1 (follow-up mode)
DB31, ... DBX2.1 = 1 (servo enable)
2.3.3

Points to note

2. Position measuring systems per gantry axis
Different types of position measuring systems can be mounted on the gantry axes of a
grouping. Furthermore, each gantry axis is capable of processing two position measuring
systems, it being possible to switch over from one system to the other at any time:
DB31, ... DBX1.5 (position measuring system 1)
DB31, ... DBX1.6 (position measuring system 2)
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Function Manual, 09/2011, 6FC5397-2BP40-2BA0
Special Functions