I tried downloading the latest config file, chopping out all extras, and setting up config again. Still no signs of life on 2.4. Tried 2.5 as well again, just in case… Setting the pin as 2.4^ or 2.4o, it also just stays high. If I use 2.4!, the pin stays low (and the laser fires continuously). Attempting to fire the laser in this case from Pronterface or LaserWeb3 does not cause any change visible on the scope on this pin either. I suppose this is good as it confirms the pin is being configured upon startup, but why setting the laser power via sXXX does not produce any change on 2.4 or 2.5 is beyond me. Based on http://smoothieware.org/laser it looks like s might be in a range 0.0-1.0, so I can try that, and it also says i can try @fire 100 in pronterface. I will have to try those tonight, after that the last thought I have is to flash the firmware again and pray.
Don, there shouldn’t be any need to connect additional ground pins on the Smoothie to the PSU other than Vbb-, would there? The laser cutter guide suggests connecting a GND from JP10 to the LPSU ground… seems redundant if Vbb minus is already connected.
So, the value after s must be a number between 0.0 and 1.0. Otherwise, the pin just doesn’t do anything. I’m surprised this isn’t in the documentation. I’m used to CNC milling and the number after S must be an integer, so it didn’t occur to me to try a decimal!
Well, now I noticed the x and y travel distances are incorrect. Although the configuration “takes” (verified in pronterface), no matter what I set alpha_steps_per_mm, for example, a 100mm move in the X produces a 50mm actual move. EDIT: it appears the board needs to be power cycled for settings on steps per mm to take effect.
@Peter_Vieth it is good grounding practice to insure that signal grounds and their current return to their source rather than some other route. Leaving off the ground will probably work but you could have noise problems.
@Peter_Vieth it is in the docs somewhere I don’t recall where 
Its also here: http://donsthings.blogspot.com/2016/12/gcode-getting-started.html
Does this mean that your PWM is working?
For the record, 4th gen FSL steps per mm is 157.48031 but 3rd gen is exactly double that.
@Peter_Vieth did you get your PWM fixed, did i miss that :)?
Hi Don, yes, it’s working now if I use S0.0 to 1.0 (well, not exactly-- it doesn’t fire when a value less than 0.2 is used… but works well enough for now!). Thanks for all your help!
@Peter_Vieth lasers don’t discharge well at low currents I think 4ma is the lowest.