I just finished getting my X-Carve SO2 upgrade kit all put together, and I’m running into an issue with the PWM control for the spindle. I’m using the 24V spindle
Using the Universal G-code sender, I can move all the axis around, home the machine, and generally do things with it. The problem is I can’t get the PWM spindle control to give me a full range of speeds from the spindle. Setting the switch to AUTO and issuing an S5000, M03 will crank the spindle up to full speed. Stopping the spindle with an M05, then sending S2000, M03 makes no difference in the speed, until less than 1000 RPM, when it starts to slow down noticeably.
Is there something I missed setting this thing up? Is there a calibration step I can do to get the spindle RPM to more closely match the commanded RPM in my gcode?
@Johanen Did you load grbl yourself, or did it come loaded from Inventables? The grbl default max speed is 1000 rpm. The Inventables max speed is 12,000 rpm. It sounds like your max speed is 1000.
The values do not represent a true speed. They represent a range. 12,000 is full speed. All numbers below that are simply a PWM percentage of full speed. All numbers above 12,000 are full speed. Setting to 6000 rpm would be PWM duty cycle of 50%.
We set our max speed to 12000 because that is pretty close to the max speed of the 24VDC spindle. None of the values will be very accurate because we are actually setting voltages and not speeds.
I had to reflash my Uno with the GRBL 9i firmware with SO2 defaults myself, since I got an upgrade kit. Is there a way to adjust this number without compiling and reflashing the grbl?
Unfortunately, this is a hard coded number. You could just live with the 1000 number and just scale your settings when you create jobs.
We can provide the proper hex file if you want to upload it using this process.
That would be extremely handy, and as an aside, we may want to include that in the instructions. The SO2 upgrade process was kind of a hot mess, and anything we can do to make future upgrade users lives easier would be super awesome.
So @BartDring hooked me up with the correct hex file for the X-Carve specific GRBL version. If you’re running into the same issue I was, send him a PM and he’ll probably be able to help you out.
A link to the grbl hex file is now in this post.