Power near max at 10%, low when near 50%

I’m back with a question on a laser cutter with a custom sendcutsend board and no documentation.

It’s paired with a cloudray myjg-150w controller.

If i fire the laser at 10%, goes to 32ma. If i increase percentage it does down. So it’s somehow flipped.

There isn’t anything in machine settings i can see that reverses a pin to fix this.

All my searches haven’t returned anything that helped solve this.

Any ideas? THANKS!

$30 is set to 1000 as is s-value
$31 0


I will assume you replaced the board or changed the wiring … ?

If it’s a grbl machine and it’s pwm is normal, it should go to H, not L, of the laser power supply (lps).

L is the laser enable pin and is active low, H is an inverted L input, being active high. This would explain the inverted power scale you’re experiencing, interpreting the pwm as inverted.

Most controllers don’t allow you to change this as it changes the definition of the pwm… as in this case where 10% pwm – inverted is 90% pwm.

This is the normal grbl… assuming you have a pot on the IN terminal.

:smile_cat: