Feed-rate: xy feed and rate set in operations list

Kiri:Moto CAM
1

I was under the impression Limits → Xy Feed

was “max xy moves feedrate” ie a maximum.

If I use the “Any Generic LinuxCNC” machine and I inspect the gcode file I can see the following lines:

G1 Y21.7475
G0 X24.2875 Y24.2875 F2000 → This is the value set in Xy Feed
G1 X140.0704 F1800 → This is the value set in operations (Outline)
G1 X139.2059 Y25.0718

If I change the the value in Xy Feed then the above line changes in sympathy.

Why?

A jerky movement prompted me to look as when the machine turns a corner the motion is very jerky and discontinuous.

Any help would be greatly appreciated.

2

In reply to my own question
G0 is Move in a straight line at rapids speed.

Which seems to take the Xy Feed value as the rapid move, and isn’t really a maximum.

3

xy feed limit should provide an upper limit to G0 and G1 and serves as a check on speed when your controller doesn’t. I can see value in a device setting to eliminate feed values for G0 commands if your firmware is providing reasonable limits. jerk should also be a controller / firmware setting that you could hard code into a device gcode header if you can’t set and persist it outside of a job.