bitboxelectronics/R2C2_Firmware — Issue #4: GCode default command
Author: bobc
Created: 2011-12-30 11:49:05+00:00
State: open

If a command line contains a valid word such as "X100" but no other G or M code, the GCode parser should implement the current modal command, e.g. G1. I think this used to work, but may have got broken somewhere.

Generally 3d printer software does not generate such commands, but it is more common in CNC/CAM files.

From "The NIST RS274NGC Interpreter - Version 3"

3.3.7 Commands and Machine Modes
In RS274/NGC, many commands cause a machining center to change from one mode to another,
and the mode stays active until some other command changes it implicitly or explicitly. Such
commands are called “modal”. For example, if coolant is turned on, it stays on until it is explicitly
turned off. The G codes for motion are also modal. If a G1 (straight move) command is given on
one line, for example, it will be executed again on the next line if one or more axis words is
available on the line, unless an explicit command is given on that next line using the axis words or
cancelling motion.