Rockwell Automation GMLC Reference Manual - Manual (Page 250)

Publication GMLC-5.2 - November 1999
Gear Axes 213
Actual position is the current position of a physical or virtual master axis
as measured by an encoder or other feedback device. This is the usual
selection—and it is the only selection when the master axis is a master
only (physical or virtual) axis—because it usually is the case that you
must synchronize the actual positions of two axes.
Slaving to Command Position
When you select Command position from the Slave to menu, changes in
the command position of the master axis generates slave axis motion, as
shown below.
Command position (only available when the master axis is a servo axis) is
the intended position for the master axis as commanded by any previous
motion blocks. Because a virtual axis is equivalent to a physical master
only axis, a virtual axis cannot be a slave axis.
Electronic Gearing
Slave Axis
Command Position Master Axis
Actual Position
Master/Slave
Gear Ratio
M
S
Electronic Gearing
Slave Axis
Command Position Master Axis
Command Position
Master/Slave
Gear Ratio
M
S