Set direct spindle speed override from external input

Hello, I want to make convinient adaptation to my new 5W laser on cnc.
I regulate power of the laser with PWM output of the spindle settings.

I want to make some indicating light from laser with Low Power freaquency using iocontrol.

I think it will be good, if I use "halui.spindle−override.direct−value" to set some 5% value when "MIST (M7)" is on and to return to previous value (mostly it 100%) when MIST is OFF. When MIST is off, spindle override should be changable.

What is the best way to do that?

Currently the issue was decided by itself.
When I turn on the lser by button F9, it turns with minimum power and after that I can regulate it by S###.

You can use F9 to turn it on and use F11 and F12 to raise or lower the intensity, if the spindle PWM is controlling the Laser PWM.
Did you check the topic for an engraver that i use, it should work with laser also, leme find it....
forum.linuxcnc.org/10-advanced-configura...mosing-a-pic?start=0

Thanks for answer. You show me very interesting method to engrave stone.
Up to this time, I saw only bar printers (hammers).