nico_1994

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Hello All,

This is my first post on this forum, but I will try to do my best to make the post as good as possible. Maybe first a little introduction about myself, I'm an electronics engineer with a big maker heart! In the past I have build myself two 3D printers with an arduino and Marlin, but never a DUET before.

Currently I'm busy building with a CO2 laser cutter, in more detail a Further Laser Y1200. This is a laser cutter designed by a youtuber and the building plans are sold on his website, in my opinion a very good opensource guide to build the mechanical part of the CO2 laser cutter. But the electronics used by him are not my favorite choice, it is not customizable... .

Research done:

Now I'm researching how to use the DUET2 ethernet that I bought to control the CO2 laser. It is the first time for me using a DUET or RRF based board, so this will be all a bit new to me. I will try to use this forum post to document how I did it and to ask questions about things I don't understand, is this allowed?

I have already researched some info of DUET3D itself:

Laser tube control:

The first thing I wane figure out is how to control the intensity of the CO2 laser. In my Y1200 build I'm using a "VEVOR MYJG80W" high voltage supply. According to it's documentation it has an input pin "IN / Control input (DAC)" that controls the laser intensity based on a analog voltage between 0 and 5V.

The power supply manufacturer asks a PWM pulse generator with a PWM frequency between 20 to 50 kHz. According to this DUET forum post it should be possible to use the PWM outputs of the DUET2 in the range of 20 to 50 kHz range, can someone comfirm this is possible for both the FAN as heater PWM's?

If I understood the DUET3D information correctly the DUET2 can only do 12V PWM for a laser on the heater / heated bed pins, they also provide a schematic to build a circuit on how to use the DUET2 still to controll the analog input of sush a high voltage supply, this can be found here.

As far as I understand the circuit it is two times a NOR gate in series, this will convert the 12V input PWM to a 5 PWM signal + an inversions. The voltage conversion is logical, the laser supply can only except 5V after all. The inversion is used because the heaters are switched low side and the laser is using high side logic.

If I was reading the documention it catched my eye that there are 3 PWM fans on the DUET2 board, these can be used both on 5 or 12V according to this schematic. Also I read in the documentation that the M452 GCODE take an argument C"name" to specify on what pin the PWM signal should be outputed.

Now I'm wondering myself, should it also be possible to configure the PWM of the fans to 5V and use one of these output with an extra software inversion to steer the "IN / Control input (DAC)" of the high voltage supply?

I can find that the "I1" argument can be used with the M106 GCODE to invert the PWM of a fan, is this also possible with the M452 GCODE?

Can anyone give me some feedback on the questions above?

Open topics:
Other topics I still wane research / figure out in the next weeks are:

Water flow sensor
Water temperature sensor
Safety contact in the casing (detecting an open casing and shut down laser automatically for eye safety), based on this forum post
Bed probing / Z-height calibration
Turning on/off LED lights
Turning on/off air assist
Turning on/off red laser dot
...

I will update this post everytime I touch on a new topic.

Already many thanks!

Br, Nico

nico_1994

@nico_1994

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