Siemens SINUMERIK 840D sl Function Manual page 165

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 $MA_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 (backlash, sag, temperature 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.
References:
Function Manual Extended Functions; Compensations (K3)
Function generator/measuring function
The activation of the function generator and measuring function 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.
Special Functions
Function Manual, 09/2011, 6FC5397-2BP40-2BA0
G1: Gantry axes
2.4 Start-up of gantry axes
165