Siemens SINUMERIK 808D Function Manual page 45

To execute this compensatory motion, the gantry grouping must be separated by means of the following machine data:
MD37140 GANTRY_BREAK_UP (break up gantry grouping)
Gantry synchronization
All gantry axes must first be referenced and then synchronized after the control system is switched on. During gantry
synchronization, all gantry axes approach the reference position of the gantry grouping in the decoupled state.
The reference position of the gantry grouping for referencing the gantry axes corresponds to the reference position of the
leading axis:
MD34100 REFP_SET_POS (reference point value/destination point for distance-coded system)
Otherwise, the reference position is the current actual position of the leading axis.
These operations for referencing and synchronizing the gantry axes are executed automatically in accordance with a special
flowchart.
Referencing process
The flowchart for referencing gantry axes using an incremental measuring system is as follows:
Section 1:
Referencing of the leading axis
Axis-specific referencing of the gantry axes is started by the active machine function REF when the leading axis interface
signal is sent from the PLC user program:
DB380x.DBX0004.7/.6 (traversing key plus/minus)
The leading axis approaches the reference point (operational sequence as for reference point approach).
The appropriate synchronized axis traverses in synchronism with the leading axis. Interface signal
"Referenced/synchronized" of the leading axis is output to indicate that the reference point has been reached.
Section 2:
Referencing the synchronized axis
As soon as the leading axis has approached its reference point, the synchronized axis is automatically referenced (as for
reference point approach).
The dependency between the leading axis and synchronized axis is inverted in the control for this phase so that the leading
axis now traverses in synchronism with the synchronized axis. IS "Referenced/synchronized" of the synchronized axis is
output to indicate that the reference point has been reached. The gantry axis dependency then reverts to its previous status.
Section 3:
Gantry synchronization
Once all axes in the gantry grouping have been referenced, they must be synchronized with the defined reference position.
The actual position of each gantry axis is first compared to the defined reference position of the leading axis.
The next step in the operating sequence depends on the difference calculated between the actual values of the leading and
synchronized axes:
● difference is smaller than the gantry warning limit:
Gantry synchronization is started automatically (provided that IS "Automatic synchronization locking" has not been set).
The message "Synchronization in progress gantry grouping x" is output during this process.
All gantry axes traverse at a specific position value in the decoupled state at the velocity set in the machine data:
MD34040 REFP_VELO_SEARCH_MARKER (shutdown speed)
The position value is defined by the leading axis:
MD34100 REFP_SET_POS (reference point for incremental system)
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 REFP_STOP_AT_ABS_MARKER (distancecoded linear measuring system without destination point)
For this operation, the axes traverse at the same velocity as set for reference point approach:
MD34070 REFP_VELO_POS (reference point positioning velocity)
As soon as all gantry axes have reached their target position (ideal position), IS "Gantry grouping is synchronized" is set
to "1" followed by reactivation of the gantry axis coupling. The position actual value of all axes in the gantry grouping
must now be identical. The gantry synchronization process is now complete.
Function Manual
01/2017
45