GRBL Fire laser does not alter power

Spark Concepts CNC controller ver4
Fire laser does work, but no mater what power level I set it at, laser is always @ 100%
Laser variable power does work durring running a job.

That’s not nearly enough information to go on. For starters, post your controller settings (type $$ in the console and hit enter, copy & paste the output here). Most likely the controller defaults the $30 setting to something dumb, like 1, which would give you on/off behavior only, whereas the GRBL default is 1000, giving you a range of 1000 possible power values.

Here ya go…

I missed the part where you said “variable power does work during a running job” - which doesn’t make much sense. The commands work the same way.

What happens if you type this into the console:
G1 S10

That should enable the laser at 1% power. S100 would be 10%

those commands turn the laser on at 100%

I just did an image earlier, so I know it can control the power.

If you did an image using the default settings, it was dithered, which uses tiny dots of full power. You’d only have gotten power control if you chose Grayscale in the pop-up cut settings box.

You’ve also given no indication of what laser you’re using, where you bought it, how it’s wired, whether you’ve verified that it works anywhere else, etc. It’s very hard to tell if the problem is a LightBurn issue, a settings issue, or something to do with the hardware or wiring.

I am using an endurance 10 watt laser diode, it uses the spindle speed (PWM) from the controller.
Let me disconnect the PWM wire and directly meter the voltage, it should vary from 0-5 volts.

Got it figured out.
It never will turn on the laser at anything less than 100%.
The PWM signal is 1.5 volts on. It only varies the time that it is on for.
With this controller, there is no power setting, it is either off or on.
A bit of a bummer, but ok I only have speed setting to play with.

From the Endurance site: “TTL wire / wires are also added to the laser driver. With TTL (3.5 - 12V range) you may change laser power (duty ratio).” That should be compatible with PWM.

It will not vary power, just on/off time.
Sent email to Spark concepts to find out what GRBL commands vary the spindle output from 0-5 volts.
Will have to build a new laser power supply to match.
Either way, I am happy with the performance of lightburn.
I appreciate all your help.