Yaskawa MotionWorks IEC - Manual (Page 363)

PLCopenPlus Function Blocks for Motion Control 2013-04-13 355
Cam Masters
An external encoder connected to an LIO card, virtual master or
Mechatrolink motion axis can be a cam master. The master is selected by
connecting it’s AXIS_REF to the Master input on Y_CamIn, Y_CamShift,
Y_CamScale, or Y_SlaveOffset.
Master Cycle
The master cycle of the cam is typically identical to the MachineCycle of
the master, although this is not required as some applications benefit from
the ability to operate a cam cycle over multiple cycles of the master
axis. The slave’s cam master cycle is available on the output of
Y_CamFileSelect or a cam slave's parameter 1512.
It is essential to understand that the cam function operates on a master
cycle which is determined by the "Last Master Position" in the cam
table. This cycle may be different than the MachineCycle set in the
Hardware Configuration. In this way, two positions for the master can be
realized.
Sewing Machine Application Example:
Consider a reciprocating needle axis which is the cam master, and must
have the ability to stop at top dead center. The cam motion for the
machine creates stitches and may require any number of cycles of the
needle axis to complete one stitch pattern.