8 Basic CNC Programming
8.4 NC Codes
99
L
Loop counter Program cycle (repeat)
counter for blocks and sub- programs,
angle of arc resolution
Single
M
Miscellaneous codes
Multiple
N
Block number (user reference only)
Single
O
Subprogram starting block number
Single
P
Subprogram reference number (with
M98 or M99)
Single
Q
Depth of cut.
Peck depth for pecking canned cycle
Single
R
Specifies the position from which to
start a drilling operation
Single
S
Spindle speed
Single
T
Tool selection
Single
U
Incremental X motion dimension
Single
V
Incremental Y motion dimension
Single
W
Incremental Z motion dimension
Single
X
X axis motion coordinate
Single
Y
Y axis motion coordinate
Single
Z
Z axis motion coordinate
Single
;
Comment
Single
8.4.1.
% Code: Incremental Arc Center
The incremental arc center code selects the Fanuc mode of programming arc coordinates. This mode is
selected for the entire NC program as well as for any chained programs.
In the Fanuc mode, arc centers are always based on incremental coordinates, regardless of whether the
system is in G90 (absolute) or G91 (incremental) coordinate mode. In contrast, arc center specifications
in the EIA-274 programming mode (specified by the $ code) follow the selected coordinate mode
(absolute or incremental).
The % character must stand alone on the first line of the NC program in which it appears.
The default arc center mode is defined in the Run Settings window, accessed by clicking Setup | Run
Settings, in the Main Menu.
8.4.2.
$ Code: Absolute Arc Centers
The absolute arc center code selects the EIA-274 mode of programming arc coordinates. This mode is
selected for the entire NC program as well as for any chained programs.
