SO4 XXL Looking for VFD Output Pin

I want to power my router automatically and figure from reading here and there to use the controller PWM output to pick a relay when an “S” command is issued to the controller (I understand PWM and needing to get 100% to get a good, clean 5V at the PWM output). What I’m asking here, is where is the proper output on my 3 month old CarbideMotion v 3.0c board.

The circled pads say “SPIO” and I’m wondering whether that PWM callout there is the proper one. I’m betting that that PWM is ONLY when using SPIO and there is another, more proper one buried in an unused connector on this board somewhere. I’m still hunting elsewhere for an answer and will pull out a scope if needed, and will post back here if I get it figured out and working.

That PWM pin is what it says, but since there is no header soldered there it may be easier to pick up the PWM signal on that other header mentioned in that post:

It’s also available on the bitrunner connector on the left side

Thanks, I poked around on the board with a meter and found that the PWM pad in my original pic is electrically the same point as the blue wire on the header shown below.

The black wire is GND. This should get me going. I’m out of the shop right now, but hope to have this all sown up by the end of the day and I’ll post up results here.

Yes, this is the bitrunner connector I was referring too. It should work fine, keep us posted.
Remember that the PWM output depends on GRBL settings $30 and $31 too to convert the requested RPM into a 0-5V voltage

All works as hoped for. I set $30 (max router speed) to 1 and $31 (min speed) to 0 since I am running with a regular old “set your speed manually” router. Whenever the GCode sees any speed >0 the PWM should go to solid +5VDC (but I did not look at it with a scope).

Used this for the relay to operate the router and vacuum as mentioned somewhere else around here. Relay works as advertised, but beware of that short-ass power cable forcing you to install the unit within 6" of an outlet. The female end of the power cable is a standard (in the US) three flat slot receptacle so you can go digging through your junk box and use the one you saved when you tossed that old crappy coffee-maker away.

1 Like

This topic was automatically closed after 30 days. New replies are no longer allowed.