Rockwell Automation 8520-MUM 9/Series CNC Mill Operation and Programming Manual Documentation Set - Manual (Page 382)

Axis Motion
Chapter 14
14-6
The system installer determines which axes are assigned to each plane in
AMP. This manual assumes the axes are assigned to the planes as
indicated below:
Circular Interpolation in XY plane
G17{G02} X__ Y__ {I__ J__} F__ ;
G03 R__
Circular Interpolation in ZX plane
G18{G02} Z__ X__ {K__ I__} F__ ;
G03 R__
Circular Interpolation in YZ plane
G19{G02} Y__ Z__ {J__ K__} F__ ;
G03 R__
Where : Is :
X, Y, Z In absolute (G90) mode, these are the coordinate values of the end-point. In
incremental (G91) mode, these are the positions of the end-point in reference to
the start-point
CAUTION: If no axis word is specified for the end-point of one of the axes in
the currently defined plane, the control will assume a value for that axis equal to
the current tool location. Specifying the wrong plane or wrong axis word for a
circular move can inadvertently generate a helical move (see section 14.1.4 ).
I, J, K These determine the position of the arc center in reference to the start-point.
These values are always incremental regardless of the established positioning
mode (absolute or incremental). I is parallel to X axis, J is parallel to Y axis, and
K is parallel to Z axis in this manual. Refer to the system installer’s
documentation for integrand words.
R Rather than defining a center with I, J, K, the option exists to define an arc radius
using R. The sign of this entry determines the arc center-point location. If R is
programmed as a positive value, the center-point will be located such that an arc
less than or equal to 180
•
is generated. If R is programmed as a negative
value, the center-point will be located such that an arc greater than 180
•
is
generated. Refer to Figure 14.5 for an example.
F Another option is to enter a feedrate tangent to the arc. If omitted, the control will
use the feedrate active prior to this block.