Light burn does not control spindle speed/laser correctly

I am using the spark Concepts CNC controller ver 4
I am running GRBL 1.1f
On my board I have a spindle speed control output (0-5 volts)
If I issue a M3 S100 command, I only get about 0.97 volts
if I issue a S1000 command I get 1.00 volts.
a S10000 gets me about 1.5 volts
an S100000 Then I finally get a 5 volt output.
I have tried this with GRBL 1.1f and 1.2g
Is there a setting I need to change somewhere?

Found my $30 was set to 100000
Set it to $30=1000 and problem solved.

1 Like

You can go the other way as well, if you need to:

That’s bizarre - When I asked you to post your settings, $30 was 1000, not 100000: GRBL Fire laser does not alter power

Glad you got it figured out.