·476·
Installation manual
CNC 8060
CNC 8065
9.
CONCEPTS.
(REF: 1402)
Home search.
considering parameter REFSHIFT. In this case, the axis will move to apply the REFSHIFT
value.
Home search with a feedback system that has distance-coded reference marks or
where none of the axes has a home switch.
The CNC starts moving both axes in the direction indicated by parameter REFDIREC of the
master axis. This movement is carried out at the feedrate indicated by parameter REFFEED2
of the master axis until the slave axis detects its reference mark. After detecting the reference
mark, the CNC resets the position value of this axis to the value set by parameter REFVALUE
and considering parameter REFSHIFT if there is one.
Then, the master axis searches the reference mark. After detecting the reference mark, the
CNC resets the position value of the master axis to the value set by parameter REFVALUE
and considering parameter REFSHIFT if there is one.
Position-Sercos axes
To homing these axes, both must either have distance-coded reference marks or a home
switch. If both axes have a home switch but do not have distance-coded reference marks,
the home switches must be placed in such way that the master axis is not pressing its home
switch while homing the slave axis (first to one to search its reference mark).
The CNC sends to the drive the command to home the slave axis. In the process, the CNC
reads the increment in the real (actual) slave position value and sends it to the master axis
as an increment of the theoretical position value, hence making the master axis follow the
slave axis only by the lag between the theoretical and real position values.
When the slave axis has been homed, the CNC sends to the drive the command to home
the master axis. In this case, the slave axis follows the master axis.
In order to prevent the axis following the one being homed from jerking due to the change
in position value, the CNC makes sure that the increment of the real position value
corresponds at the most with the homing feedrate (parameter REFFEED1) and that it does
not exceed the maximum acceleration allowed for that axis.
When both axes have been homed, the CNC takes into account the difference between the
position values to correct it, if so permitted by parameter DIFFCOMP.
Coordinate (position) difference compensation after a home
search.
The CNC corrects the position difference between the master and the slave axes after they
are homed. The position value correction (compensation) may be applied to any type of axis;
analog, position-Sercos and velocity-Sercos.
Position value compensation is enabled by parameter DIFFCOMP and it is applied with
marks DIFFCOMP(axis) and SERVO*ON(axis) as follows.
• With the up-flank of SERVO*ON if DIFFCOMP is active.
• With the up-flank of DIFFCOMP if SERVO*ON is active.
To compensate the position value, the slave axis will move until reaching the position of the
master axis at the feedrate set by parameter REFFEED2. This process can only be
interrupted with RESET. The REFPOIN(axis) mark of both axes is activated when the
position value compensation is completed.
Parameter. Meaning.
DIFFCOMP Compensate for the coordinate (position) difference
between the two axes after G74.
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