#define SPINDLE_MAX_RPM 1000.0 How to find this and change it?

M3S10000 is full on 5 volts for the PWM . Any SXXXXX command over 10000 doesn’t get recognized, which means my 24000 rpm spindle can never go above 12000 rpm and my cad software sending M3S20000 or other Sxxxx settings isn’t doing any good.
My question is can I change the limit so that M3S10000 can be changed to M3S24000 for max 5 volt on the PWM?

Which version of GRBL are you running?

I’m pretty sure it is .9. I’m bit clueless about the grbl stuff but only cause I haven’t taken the week to wrap my head around it. Any help would be much appreciated.

Edir: looks like version 1.1 you can edit it at $30 ???

In v1.1 you can edit max and min speed.

$30=max Spindle speed
$31=min Spindle speed


I finally updated to grbl 1.1 and can now control the speed of my spindle better.
On a side note I’m not really liking CM4 ( log file and manual commands don’t always respond $H).
I’ll play with it more tonight and hopefully figure it out more.
Thank you for your help Lewscrew, it is much appreciated.