Folks,
I have a Fanuc 0i Mate TB gang tool lathe with full C-axis capability and I'm running into a problem coding up some circular interpolation codes (G02) within the G7.1 cylindrical interpolation mode. G18 is the default plane of operation for this machine.
Here's the problem:
Once I get into the G7.1 mode I can execute G1 linear movement with no problem but the control throws an error "21 Illegal Plane Axis Commanded" as soon as it reads one of my G2 blocks. Just for background, trying to command G17 or G19 throws a "28 Illegal Plane Selected." So, G18 would seem to be the plane to stick with and most of the references I've seen indicate G18 is for "ZC" plane.
A segment of the code is as follows:
G98 (IPM required for G7.1)
G18 (this is the default)
M21 (get into C-axis mode)
...
G1 X.500 F200
G1 Z0.
G7.1 C.250
G28 H0.
G1 Z-.5 C90. F200 (works)
G1 Z0. C0. (works)
G2 Z-.25 C90. R.500 (alarm 21)
...
So, the linear ZC commands work but as soon as the control reads the G2 ZC command it throws an error. I don't think the control really cares about G18 when it's doing linear commands because I can execute a three dimensional XZC G1 command.
Here's my guess but I'd like considered opinion:
Parameter 1022 is set
X 1 (X axis of basic three)
Z 3 (Y axis of basic three)
C 5 (Axis parallel to X axis)
The C axis setting looks odd as maybe it should be set to 7 (Axis parallel to Z axis) so that the control isn't trying to translate a G2 ZC command into an X axis travel per that parameter. The C axis really is parallel to the Z axis so maybe changing this parameter would make all consistent.
Please let me know what y'all think as changing parameters is not my favorite thing - seems dangerous. Or is there something else I'm overlooking?
Thanks, folks.
Cheers,
Rich