Primo build progress

I’m hoping I can get the spindle wired tonight and do some testing with the skr fan output controlling spindle speed.


nice control box.


Ok, so the fan output does actually control spindle speed but i think its going to take some additional electronics to make it work.

Going to play with it more this weekend. It seems as though it goes 100% at 5v instead of 10, and the signal isn’t very steady.

I have some experience with VFDs (i did HVAC controls for a few years) what are you using? And how are you integrating it with the control board?

I’m just hacking at this. I think I just need a pwm to analog voltage converter.

I was hoping the fan output voltage change would be enough but that doesnt appear to be the case from what im reading.

The 0-5v issue was a setting. It apparently offers both 0-5 and 0-10v options in the config

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If your board has an extruder temp output use that instead

That would require a complete rewrite of the firmware vs a $9 electronics board

I guess its what your more comfterble with… I don’t think it would be that major of a firmware change… some Vfds offer pulse inputs if I knew the model I might be able to find another way.

Amazon delivery will have it here tomorrow. Considering I just took the existing fan menu and made my edits to it, I have no idea how to change everything from the fan to another output. Nor where to even start.

Upon further review you are correct… spinal speed can only be set to a pwm output.

Just throwing the idea out there. But would you be able to drive a vfd using the fan pin and wiring as if you were using a 5v fan on a 24v system then reassign the pins?

Not without the board mentioned earlier… or a VFD that accepts a pwm input signal.

Yes, I didn’t get to update. $10 part worked perfectly and it fits inside the vfd cover.

Vfd also has a 24v output on one of the terminals that I was able to power the board there, without needing an additional power supply.

Only issue I have is the scale isn’t 100% accurate but thsts more because of the electronics than anything else. 50% spindle speed is more like 58% close enough for me

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there may be a parameter in the VFD where you can rescale the input. if your happy with it then what ever, but if it gets to bug you then there is an option.

The China vfds aren’t exactly linear apparently. I had to choose whether I wanted the lower values to match, or the higher ones.

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i would give you the nice Altivar i have, but unless you have 480V it probably wouldn’t help much XD.

I do, but this doesn’t need to be that accurate lol.

Testing now. I need to build the enclosure next.

Looks great! I can’t wait to see the enclosure!

Fingers crossed