Hi,
I was curious why during engraving, the dialog of ‘Move’ changed to ‘Speed’ and ‘Power’ adjustments and you can increase the power up to 200%.
Does it mean on the ‘Layer’ dialog, the ‘100%’ power setting is only actually ‘50%’? Is there any way I can set the power to ‘real’ 100%?..
Thx and happy holidays
I did some testing and signal analysis of the grbl PWM output, which drives the effective power output of the laser. I found that “S” command values (PWM power) equal to and greater than 100% drove the signal to full power, solid High state, but with conditions. When using M4 command to enable cutting (Spindle enable), and grbl is in laser mode ($32=1), then the PWM signal (laser power) varies proportional to the feedrate as grbl varies the realtime feedrate in order to corner sharp angles and arcs during a sequence of moves. This variance of feedrate is not very noticeable to the observer or operator of the XY axis or cutter, and its highly dependent on the programmed feedrate as well as the grbl configuration with regard to XY acceleration values for a specific machine model and hardware. When S is programmed greater than 100%, then that raises the threshold when PWM drops below 100%. Meaning, S @ 110% will not fall below 100% until the feedrate drops to roughtly 89% of programmed value. This behavior can be used by the operator to alter when and how quickly PWM responds to a change of realtime feedrate during a cut.
Here is more info on laser mode, M4, and PWM. Grbl v1.1 Laser Mode · gnea/grbl Wiki · GitHub
and here: Grbl v1.1 Configuration · gnea/grbl Wiki · GitHub
The background story is that I did this testing a few months ago in support of a circuit I built for plasma cutting which uses the PWM signal at preset duty cycle values I established to enable and disable the Z axis motor at times when the XY feedrate dropped too low for good THC control of Z.
This topic was automatically closed 30 days after the last reply. New replies are no longer allowed.