Siemens sinumerik 840D sl Function Manual page 150

Detailed description
2.2 Referencing and synchronization of gantry axes
Referencing direction selection
The zero mark leveling function of the slave axis can be defined via the machine data:
MD37150 $MA_GANTRY_FUNCTION_MASK Bit 1
Bit
1
During referencing, the reference point value of the leading axis is specified as the target
position for all axes in the grouping for the synchronization compensatory motion. This
position is then approached without axis coupling. The absolute encoders and distanced-
coded encoders of the leading axis will be set to the current actual position of the leading
axis or to the reference point by the following machine data:
MD34330 $MA_REFP_STOP_AT_ABS_MARKER (Distancecoded linear measuring system
without destination point)
If only one reference cam is used for the leading and synchronized axes, then this must be
taken into account in the PLC user program.
2.2.2 Automatic synchronization
Automatic synchronization can take place:
• in referencing mode (see Section "Detailed description", "Introduction")
• in other modes, as described in the following.
If a gantry grouping is switched to follow-up mode, monitoring of the actual values between
the leading and synchronized axes is disabled. The grouping is no longer synchronized as a
result. Independent of axes positions, the following interface signal will be set to 0 (from
leading axis)
DB31, ... DBX101.5 (gantry grouping is synchronous)
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)
18
Value Meaning
0 The zero mark leveling function of the slave axis analogous to the machine data:
MD34010 $MA_REFP_CAM_DIR_IS_MINUS
1 The zero mark leveling function of the master axis is the same as the slave axis
Special functions: Gantry Axes (G1)
Function Manual, 11/2006, 6FC5397-2BP10-2BA0