Gcode M67 power output rounding issue

[itsbrian (brian)]

I am currently testing out Lightburn to generate the gcode for my machine that uses LinuxCNC. So far it has work great. The only issue I am seeing is the power output only incrementing in percentages of 10.

For example, when I set the power output to 5% this results in the following gcode:

M67 E0 Q0.1 ;This should be Q0.05

Anything less than 5 gets round down (ie. 14% Power output results in Q0.1) and anything greater than or equal to 5 gets rounded up (example above). Is there a setting to increase the resolution for the power output anywhere?

[jkwilborn (Jack Wilborn)]

The software generates these values based on maximum/minimum spindle speed entries.

So I’d check that these same values exist across all the platforms.

[itsbrian (brian)]

Ohhh, I see how I can make this work. For anyone wanting more detail:

1. In Lightburn go to the toolbar > Edit > Device Settings
2. Change S-value max to 100. So at 100% duty cycle it will output Q100. Mine out of the box was 1.
3. In LinuxCNC make sure to scale this accordingly in your hal file, example: setp pwmgen.0.scale 100

I was thinking the S-min max at 1 would work, but I’m imagining there are programming limitations with decimals. Scaling it solves the problem to get into the integer range.

Thank you for your help!