Laser Advice and Guidance - Mesa Card

With my primary project/mission complete in large part to the help I've received on this forum I'm now looking at adding a laser etch/engraver head to my CNC router.

With a Mesa 7i96e card or similar, can I etch in grey scale?

I've read some posts from circa 2013 and the method was to use G67 plus a phantom Z motion to control the laser. Is there a more refined method today?

I use Fusion 360 as a one stop shop for CAM and generating g-code. Is there a better work flow and software option for laser engraving?

I currently use the Axis GUI as it does everything I need it to do as a beginner/novice. Is there a better suited interface/GUI for lasers?

Any advice is appreciated.

You could certainly use the Z axis for setting a PWM value

You would want to set very high accel/velocity values for Z or alternatively
set a very high z scale number so that the range of numbers used for PWM control
were a small fraction of the (imaginary) Z axis position range

PCW wrote: You could certainly use the Z axis for setting a PWM value

Which is possibly inelegant, but does mean that image2gcode can be configured so that you can simply open a bitmap file in the Axis UI and it will "just work"
www.linuxcnc.org/docs/html/gui/image-to-gcode.html

PCW wrote: You would want to set very high accel/velocity values for Z or alternatively
set a very high z scale number so that the range of numbers used for PWM control
were a small fraction of the (imaginary) Z axis position range

What if my Z axis can't achieve fast enough accel values? Will the motor just stall and hum? And wouldn't the heat build up be bad?

Can I leave the Z axis as is and use a phantom A axis set to a high value or does LinuxCNC need to see hardware (stepper motor)?

I assumed Z was driving the laser PWM value so there are no velocity
or accel limits

Not sure A is a good choice for modulation due to blending/lookahead
limitations of the standard TP

PCW wrote: I assumed Z was driving the laser PWM value so there are no velocity
or accel limits

I'm still trying to wrap my head around this implementation.

I read through this wiki Rastering_With_A_Laser probably need to read it a couple more times. Know of any other examples?

Project_Hopeless wrote: Can I leave the Z axis as is and use a phantom A axis set to a high value or does LinuxCNC need to see hardware (stepper motor)?

If you have an actual height adjustment axis then I would suggest configuring that as W and using a "phantom Z" to control PWM. Also set the Z so it moves a _tiny_ virtual amount between 0 and 100% PWM to minimise the effect on the trajectory.

M67 ought to be the correct way, but rumours are circulating here that it slows the motion (though it shouldn't)

I like the idea of ​​controlling laser power via Z-axis.
But I'm not sure how to connect it.
Maybe you can help me.

For the test, I loaded the PWM bitfile onto my 7i76e simulator.
The following lines are written in the hal.

I have now loaded a picture in linuxcnc and started the program.
I think I can get a finer structure on the lasered picture, which there is still to try.
On TB3 pin 2 and 3 I now measure 20Khz and a nicely fluctuating voltage between 0-12V depending on the height of the Z-axis.
So I can easily adjust the power of the laser with the engraving depth.
Now two questions.
Why 12V? I thought PWM was only 5V. Background: the Borad once had a short circuit. Are that 5V on a healthy board? Because laser has only  5V PWM connection.

And how can I connect the laser to the board? I only have 3 cables on the laser. PWM, GND and 12V 

The step/dir outputs (being used for PWM now) on a 7I76e are 5V signals
I suspect a measurement error

PCW wrote:

The step/dir outputs (being used for PWM now) on a 7I76e are 5V signals
I suspect a measurement error

Okay i measure now TB3 Pin 1 an 2 and got 5V max. I would wired laser this way but have fear to share thre ground.
Laser PWM -> TB3 Pin 2
Laser GND -> -12V Powersupply
Laser 12V -> +12V Powersupply
Or should  i better use  a level converter between Laser PWM and TB3 on mesa board to not share the ground?