How to invert 0-10V output/

Hi Im new to linuxcnc and have no idea about .ini and .hal yet. I'm using my CNC for laser engraving. And it was working fine on wood but when I switch to granite it seems powerless so I start measurements and noticed by using a PWM pin laser working only on 600mA(should be 1.8A) on 100% PWM. I can't figure out how to get full power from PWM so I change to 0-10V pins and it's working well now but my problem is when I use M68 E0 Q1 it's 0V and M68 E0 Q0 is 10V. How to invert it?
I will try to attach my config files because I was using "Marco Reps" youtube tutorial because setting laser power by S* was to slow.
 

In your custom.hal add
setp parport.0.pin-01-out-invert TRUE
so
net analogout motion.analog-out-00 => pwmgen.0.value
net laserpwm pwmgen.0.pwm => parport.0.pin-01-out
looks like
net analogout motion.analog-out-00 => pwmgen.0.value
setp parport.0.pin-01-out-invert 1
net laserpwm pwmgen.0.pwm => parport.0.pin-01-out

It's working perfectly now. I saw this phrase before but without any idea where to put it and which pin number.
Do you know if the 0-10V output is any "slower" than PWM if I need it to rapidly change the power of my laser? I want to know if I should start figuring out why PWM not giving full power or if I can just forget.
Thanks again.

Check at what rate of the PWM your laser can reliably work first.
I would venture a guess that 1-5KHz should work in most cases, but i have seen ones that require lower and/or higher rates.

Could I ask you where I can manipulate my PWM freq? When I'm looking for a solution on google I see people have command in .ini but i don't see same command in my .ini

linuxcnc.org/docs/html/man/man9/pwmgen.9.html
Near the end, pwmgen.N.pwm-freq

This is set in hal file example like this :