Siemens SINUMERIK 808D Function Manual page 52

This difference must be applied as the reference point offset:
MD34080 REFP_MOVE_DIST (reference point distance)
MD34090 REFP_MOVE_DIST_CORR (reference point offset/absolute offset)
Synchronizing gantry axes
The gantry synchronization process must be activated with IS "Start gantry synchronization" (see Section "Referencing and
synchronizing gantry axes (Page 44)"). Once the axes have been synchronized (IS "Gantry grouping is synchronized" = 1),
the dimensional offset between the leading and synchronized axes must be checked to ensure that it equals 0. Corrections
may need to be made in the machine data mentioned above.
Input of gantry warning limit
Once the reference point values for the leading and synchronized axes have been optimized so that the gantry axes are
perfectly aligned with one another after synchronization, the warning limit values for all axes must be entered in the following
machine data:
MD37110 GANTRY_POS_TOL_WARNING (gantry warning limit)
To do this, the value must be increased incrementally until the value is just below the alarm (limit exceeded) response limit.
It is particularly important to check the acceleration phases.
This limit value also determines the position deviation value at which gantry synchronization is automatically started in the
control.
Calculating and activating compensations
In cases where the gantry axes require compensation (sag or leadscrew error), the compensation values for the leading axis
and the synchronized axis must be calculated and entered in the appropriate parameters or tables.
Refer to Section titled "Compensation (K3) (Page 103)".
Function generator/measuring function
The activation of the function generator and measuring function using the startup tool will be aborted on the synchronized
axis with an error message.
When an activation of the synchronized axis is absolutely necessary (e.g. to calibrate the machine), the leading and
synchronized axes must be temporarily interchanged.
Note
Generally, the start of the function generator, measuring functions and AM setup triggers the virtual axes to abort upon error
recognition.
Special cases
If individual axes have to be activated, the gantry groups must be temporarily canceled. As the second axis no longer travels
in synchronism with the first axis, the activated axis must not be allowed to traverse beyond the positional tolerance.
If the gantry grouping is canceled, the following points must be noted:
● Always activate the traversing range limits and set them to the lowest possible values (position tolerance)
● Synchronize the gantry grouping first if possible and then execute a POWER-ON-RESET without referencing the axes
again. This ensures that the traversing range limits always refer to the same position (i.e. that which was valid on power
ON).
● Avoid using the step-change function. Position step changes are only permissible if they stay within the permitted
tolerance.
● Always use an offset of 0 for the function generator and measuring function in contrast to the recommendations for
normal axes.
● Set the amplitudes for function generator and measuring function to such low values that the activated axis traverses a
shorter distance than the position tolerance allows. Always activate the traversing range limits as a check (see above).
52
Function Manual
01/2017