This is the video I meant to link to:
https://www.flickr.com/photos/22787396@N02/51859597943/in/datetaken/The PWM runs continuously and the S### word is updated during the G00 moves (when the laser is OFF) with M3 only used at the start of the Gcode and M5 at the end. The laser is switched ON/OFF with the gated PWM / axis Direction signal and this does not break the CV chain so there is no delay in the switching sequences.
It would not be possible to produce Greyscale images using this method.
Way back then, I used the Mach3 Laser/Impact engraving plugin for greyscale images but that can’t be used with USB PC connections (Parallel Port only).
Although I have not tried it, I understand that Mach4 will now allow the M3 S### command to be changed ‘on the fly’ without breaking the CV chain – this may be another possibility worthy of consideration but Mach4 is currently lagging behind in the world of Laser control.
Tweakie.