Can't get LinuxCNC to stop taking "shortcuts"

knipknap wrote:

I randomly get situations where LinuxCNC is not following the gcode precisely, instead taking shortcuts. I have configured G64 as follows:

RS274NGC_STARTUP_CODE = G17 G21 G40 G49 G64 P0.001 G80 G90 G94 G97 G9
 

RS274NGC_STARTUP_CODE is only valid during startup, do not expect any of those codes to last past the first line of the first G code program you run.

The RS274NGC_STARTUP_CODE does not take the place of a good preamble in each G code file.

G code programs can change anything while running and thus render the RS274NGC_STARTUP_CODE a waste of time.

linuxcnc.org/docs/stable/html/gcode/over...gcode:best-practices

JT

knipknap wrote:

Sure, I already put that into the preamble of future gcode files, but I don't think that's a good excuse to leave the machine in an inconsistent state depending on how it was switched on.

from the docs

RS274NGC_STARTUP_CODE = G17 G20 G40 G49 G64 P0.001 G80 G90 G92.1 G94 G97 G98 - A string of NC codes that the interpreter is initialized with. This is not a substitute for specifying modal G-codes at the top of each NGC file, because the modal codes of machines differ, and may be changed by G-code interpreted earlier in the session.

So when you start LinuxCNC the the interpreter is initialized with RS274NGC_STARTUP_CODE.

JT

Might be related to this issue that was fixed in 2.9:
github.com/LinuxCNC/linuxcnc/commit/6bc4...27f7d81c978ff5050436

This patch fixes #177, "Forgetting G64 mode after E-stop,"

That's a huge problem, wonder how long it existed?

JT