Wiring VFD to GRBL for spindle control?

Does anyone have a way to explain to a dummy how to connect my Carbide board V2.4d to a cheapo VFD. I’d like (if possible) to have it turn on/off, control forward and reverse and rpm? Crayon drawings preferred

Many thanks!

Here’s for the crayon drawing and a short explanation:


The pinout for 2.4d is discussed here, to locate PWM signal:

Then it all depends on what VFD you have, to setup its parameters.
There’s a thread for Huanyang VFDs configuration here:

That should allow you to turn the spindle on and off, and adjust RPM. It’s not straightforward to control forward/reverse, you would need an additional signal for that.

And then ask additional questions here, many people have done this and will be in a position to help you.

1 Like

Still a bit beyond me, I’d love to utilize these functions, but some of the posts I read are a bit Greek to me. I have just purchased the Huanyang “Inverter” and it’s the first time I have ever interacted with one. I was really proud when I successfully wired up the spindle (I know I know). So it may be out of my league. I see the bank of 6 pins on the board, where oh where do they all get connected into my VFD? If this is too laborious to explain to me, I understand. The reason I am venturing this far out of my comfort zone is, I have NOTHING else to do until this virus goes away.
Thanks either way!
Stay healthy

Going to sleep right now but if nobody else answers first I’ll be happy to explain in détail tomorrow!

Do you really think you need Reverse; I only wired forward rotation and can’t see the need for it to turn backwards

Probably do not need reverse, but if I were going to the effort of running wires I was going to. Seems to me that you’re quite experienced, so I’d go with your recommendations

remember that to run reverse you also need a reverse endmill with the sharp sides on the other rotation…

I wired an Emergency Stop (Normally Closed) Mash Button between FOR and DCM. Normally many people just sort them with a small wire. But the bottom allows me to press it while I’m changing bits, the VFD in while in RPM mode will start flashing. I feel more comfortable having the VFD with a double safety (PWM signal setting 0 RPM and the FOR signal disconnected by the switch). I recommend doing that.

You need to wire the PWM signal from the Shapeoko controller board to the VI signal on the VFD. You’ll also need to sire the Ground signal from the Shapeoko controller board to the ACM. You’ll need to make other changes to the VFD and move a jumper on the VFD. I soldered pins onto my controller board to make these connections but I heard some talk about press in connectors which would have been much easier.

You’ll need to make other changes to the VFD parameters and also set $30=24000 and $31 to 0. I’ll let someone else pick it up from here

That’s excellent advice. I’ll check how my VFD behaves when FOR is temporarily not shorted to DCM.

@snapajap, I think @wb9tpg nailed it with that short summary, that’s all there is to it in terms of wiring.
And then, since you have the same Huanyang inverter (VFD) as many of us have, setting the parameters should be easy since you will have examples/reference values. Let us know your specific questions if anything is still unclear.

Damn, thank you very much! I’ll be starting this project today, if I have time…Oh wait, I have time :slight_smile:

I can’t thank you enough. What a great community this is. I’m sure I’ll be back asking more questions today, but thanks.


So, is there any need for a SuperPID, or can we just wire the PWM wire from controller board to the VFD?

The VFD takes an analog input signal (typically 0 to 5V, or 0 to 10V) to drive the RPM, so you just have to wire the Shapeoko controller’s PWM signal to that VFD input: the modulation of the PWM signal by GRBL (based on RPM value in the code) will produce a square signal that on average is somewhere between 0 and 5V.

SuperPID is a different beast, it modulates the mains power to a regular power tool like a trim router. You could say that a VFD is kind of like a “SuperPID for spindles”


Just wire the PWM signal directly to the VFD Vi input. If fact I wired mine to the laser in parallel with it and it’s working great to both.

1 Like

Thanks guys. As soon as I get the hang of the CNCjs, an upgraded 2.2kw spindle will the next evolution.

I just found this and it shows where you can find PWM and Ground on the Shapeoko board. The video is for a laser but it’s the same for the spindle and you can parallel them if you have both


Yes sir, that looks pretty simple.

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