How do I reverse pwm signal?

[chenewer]

I have a jtech laser connected to a gecko g540 and uc400eth. When I send m3s1 the laser turns on full power. When I send the m3s100 the laser sends the lowest power. In mach3 it works as it should.

Here's how I connect the laser.

[cncdrive]

The Active low checkbox of the laser pin inverts the PWM.

[chenewer]

No reaction to active low.
Still the same.

[chenewer]

When I put pwm min% 100 and max% to 1 it gets right. But still the image in the laser engraving plugin becomes negative.

[cncdrive]

How do you program the laser? With M10/M11? If yes then it reacts to the laser output checkbox signal, it inverts it. Or if you programming it with spindle speed S code then it will react to the active low setting of the PWM spindle PWM pin.
But it is recommended to code the laser with M10/M11 and not with S codes, because you can get much better results wiht the M10/M11 as the S command is not a motion syncronous command and so it is unoptimal for laser use.

[chenewer]

Does laser engraving plugin use m10/m11?
I have tried to engrave a picture in the laser engraving plugin (grayscale) but it comes out as a negative. Black is white and white is black.
Active low has no effect at all.
If I set pwm min duty % 100 and max% to 1, I can increase the strength of the laser normally with m3s1 to m3s100.