Rockwell Automation 8520-GUM 9/Series CNC Grinder Operation and Programming Manual Documentation Set - Manual (Page 389)

Axis Motion
Chapter 12
12-17
Circular QuickPath Plus helps the programmer when a drawing does not
call out the actual intersection of two consecutive paths and at least one of
the paths is circular. This provides the programmer with the option of not
having to do any complex calculations to determine end points and start
points when an arc is involved.
For most cases of circular QuickPath Plus there are two possible
intersection points for the two defined blocks. Which intersection is used
is determined by programming either G13 or G13.1 in the first of the two
blocks:
G13 First Intersection
G13.1 Second Intersection
Programming G13 defines the first intersection that occurs when the path
of the first block intersects with the second block. Programming a G13.1
defines the second intersection that occurs when the path of the first block
intersects with the second block.
Figure 12.10
G13 versus G13.1 Intersections
Second block if G13 programmed
Second block if G13.1 programmed
1st block
1st block
12150-I
When programming Circular QuickPath Plus, remember:
When there is only one intersection involved with the paths, the G13
and G13.1 can be programmed interchangeably. One of these G--codes
still must be programmed
The G13 or G13.1 must be programmed in the first of the two blocks
defining the two paths
If the arc is programmed with an R--word, the two paths must be
tangent. The sign (+ or -) of the R--word determines the arc center
location as described on page 12-5
12.2.2
Circular QuickPath Plus
(G13, G12.1)