jegb
commented
8 years ago I would try to update this, we found that the lasercutter ignores this frequency from visicut, and the power setting for that matter. -we are experimenting with our power supply, to understand if the laserON signal could be used as PWM, and leaving the analog signal (where the poti is connected) still in use for manual fine control. if the power supply performs up to 5khz, then we are fine, although we may break it is worth the try.
This could enable the usage of cutting in a sort of dot mode, where "secretly" the laser isn't on continuously but is turned on and off very fast. Because a lasercutter is more powerful when it's just turned on this could enable you to burn through thicker material with nicer looking cuts.
pbrier: Adding the ability to modify frequency is easy in firmware. But: It will not help if your laser (power supply) is not capable of pulsed operation. Most DC gas lasers are CW (Continous Wave) lasers and not pulsed (like the more expensive RF (Radio Frequency) lasers in Epilog, Trotec and Universal laser systems). If the PWM is used to modulate the laser power via the analog input of the power supply, changing the PWM has most likely no effect (apart from bad PWM to power linearity if the frequency is too high or too low). If the laser power supply is capable of quickly switching the laser on and off, frequency modifications make sense. In this case the PWM signal has to be routed to the laser ON input. I am not sure if switching the laser ON input quickly (at 5 to 10khz) kan damage power supplies that are not prepared for this, and I also do not know if would give improvements in peak power or beam quality. We would need to do some measurements.
peteruithoven: Peter, you mean that the PWM isn't actually used as PWM but it's translated into a analog value because you hook it up to the analog input of the power supply? And so just changing the frequency of the PWM won't really allow you to control the beam? Control like you can't make it laser dots at a specific interval? Well, this means it's interesting to have a optional frequency support anyway in VisiCut I guess.
pbrier: The PWM is turned into an analog signal by the laser power supply (it has a low-pass filter on this input) to control the laser current. If you want a specific DOT interval, you can use the raster mode (the LAOS board allows arbitrary angles for raster lines, but Visicut does not support this). OR: Hook up the PWM output to the "LASER ON" input of your power supply. (needs a small firmware patch to switch PWM to "0" if the beam should be OFF"). I cannot guarantee that your chinese laser power supply is capable of handling high speed pulses on the input.
Source: http://redmine.laoslaser.org/issues/78