Rockwell Automation 8520 9/Series CNC Lathe - Manual (Page 367)

Axis Motion
Chapter 14
14-9
This section describes how to program a rotary axis. A rotary axis is a
non-linear axis that typically rotates about a fixed point. A rotary axis is
not the same as a spindle which uses an M19 to orient to a specific angle.
A spindle orient (M19) cannot move simultaneously with the other axes in
the system. A rotary axis is capable of rotating when other axes are being
moved.
Your system installer must determine which axes are rotary axes or linear
axes, in AMP. Your system installer also determines in AMP the address
that is used to command a rotary axis. This manual assumes that the
C-word is used to program a rotary axis. Refer to your system installer’s
documentation for the rotary axis words used in a specific system.
A rotary axis is programmed in degrees. This manual assumes that your
system installer has configured the rotary axis to “roll over” at 359.99
° .
After the rotary axis exceeds 359.99 ° of rotation, its position display rolls
over to 0 ° and starts increasing. If the axis rotates to a position less than
0 ° , its position display rolls over to 359.99 ° and starts decreasing.
Typically a rotary axis is programmed in a block by itself or with linear
moves (rapid G00 or cutting G01 moves). You can program a rotary axis
in a block that contains circular moves (G02 or G03).
Programming in absolute or incremental
You can program rotary axes in absolute or incremental mode.
In absolute mode (G90), the rotary axis is programmed to angular
positions. These positions are programmed between 0
° and 359.99 ° . The
sign given to this angular position determines the direction that the rotary
axis travels to reach the programmed angle. For example, programming:
G90C25;
in a part program causes the rotary axis C, to rotate to an angle of 25 °
(referenced from a position 0 determined by your system installer) and
rotate the axis in the positive direction to reach this position.
Programming:
G90C-25;
in a part program causes the rotary axis C, to rotate to an angle of 25 ° and
rotate the axis in the negative direction to reach this position.
14.1.4
Positioning Rotary Axes