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Installation manual
CNC 8055
CNC 8055i
7.
CONCEPTS
SOFT: V02.2X
Reference systems
Gantry axes. Managing two home switches
Managing two home switches is only possible if axis machine parameter I0TYPE (P52) =3.
If both the master and the slave axes have a home switch (axis parameter DECINPUT (P31) of the
master and slave are YES), the home search will be carried out as follows:
The CNC starts the movements of both axes in the direction indicated by axis parameter
REFDIREC (P33) of the main axis.
This movement is carried out at the feedrate indicated by axis parameter REFEED1 (P34) of
the main axis. The axes move until one of them presses its home switch.
Then, the home search will start on the axis that pressed the home switch first at the feedrate
indicated by axis parameter REFEED2 (P35) of the main axis.
Once the first axis has been homed, its coordinate is initialized with axis parameter REFVALUE
(P36) and it starts homing the other axis.
Master and slave start moving together at axis parameter REFEED1 (P34) of the main axis until
detecting the home switch of the second axis.
It, then, starts homing the second axis at axis parameter REFEED2 (p35) of the main axis and
once detected, it initializes its coordinate.
After this, depending on the value of axis machine parameter DIFFCOMP (P96), it will
compensate for the difference between the master and slave axes or it will leave
uncompensated.
If the master axis is the first one to press the home switch and its axis parameter REFSHIFT
(P47) is other than zero, it does not start the second home search until executing the movement
for the REFSHIFT (P47) on the master axis.
Special cases
• If when starting the home search, either the master or the slave is pressing the home switch,
the axes will move until releasing the home switch and it then homes that axis first.
• If when starting the home search both the master and the slave are pressing the home switch,
it first homes the master axis.
• When commanding a simultaneous homing of the gantry axis and other axes; it first moves all
the axes having a home switch until all the home switches are pressed (in the case of a gantry
pair, one of the home switches will be pressed).
After this, if I0TYPE (P52) =3, the axes move one by one to release the home switches and search
home in the selected order.
Managing the alignment between master and slave using a PLC mark and a machine
parameter
After homing both axes of the Ganty pair, if axis parameter of the master DIFFCOMP (P96) = 1, it
corrects the position difference of the slave so the coordinate difference between the master and
the slave is zero.
Whether parameter DIFFCOMP = ·1· or = ·0·, the difference between the Gantry axes may be
corrected at any time using the PLC marks SERVOaxisON and the DIFFCOMaxis where "axis" is
the name or the logic number of the master axis. The theoretical difference between the master and
the slave is corrected as follows:
• With the leading edge (up flank) of DIFFCOMaxis while SERVOaxisON = 1.
• With the leading edge (up flank) of SERVOaxisON while DIFFCOMaxis = 1.
In this case, to correct the theoretical difference between master and slave, both the master and
the slave axes must be set as Gantry axis or as DRO axis. Otherwise, the upflank of the
SERVOaxisON mark corrects the following error of the slave axis.
Besides, the value of axis machine parameter MAXDIFF (P97) is taken into account when it is about
correct the position difference.
If the position difference between master and slave is not compensated because the coordinate
difference is greater than the value of axis parameter MAXDIFF, PLC mark MAXDIFFaxis will be
activated. In this case the PLC can issue a warning.
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