What is the current mapping of RPM to PWM please?

Hi All,

Currently adding a laser to my X-Carve and it will get its power level control signal by tapping into the PWM signal coming out of pin 11.

Having trawled the forums I’ve seen mentioned that 100% duty is 12,000 or 14,000 requested RPM in Easel. I’ve also seen the default RPM set at 18,000 in Easel. Hence I’m confused.

What RPM do I need to set in Easel to ensure a 100% duty cycle on pin 11?

Is this linear to 0 RPM giving 0% duty on pin 11?

I know it’s not terribly important for spindle control but a good mapping will help laser control.

Thanks in advance.


100% is 12000 and 0% is well 0 rpm so if you map 0-1024 to 0-100 that will give you what you need. with lasers you also need to control power not only pwm.

you can set the rpm to anything 12000 and above to get 100%

yes it is linear

you could always find in the firmware where it maps the rpm from gcode and it will give you the exact equation


Thanks Nick.

I did have a dig through the GRBL firmware but I got a bit lost.

I will look tonight and actually see how they map it.

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