Centroid Acorn CNC: Control Spindle RPM on DC Motor Controllers

[@acwrightdesign]

Thank you for demystifying my Sherline motor control box! I will be doing the exact same setup for Acorn control of my motor. Great video!

[@EZ_shop]

Good job Franco. Love this series on the Acorn

[@FrancoCNC]

Thanks. I've been working on solving this problem (controlling DC Spindle Drives with DIY CNC hardware) for several years. The key was the KBSI-240D board.

[@kenjames6172]

I'm trying to set up a spindle drive How do you set what output number for forward and reverse

[@kpshc707]

Can do a video of some internal tapping with this machine?

[@andrewaydelott6953]

Can you use that iso board to control it via Acorn and usa a potentiometer as a manual override?

[@deondaugherty6723]

Did you get forward and reverse working for the lathe? How did you wire it?

[@David.Munson]

great stuff. can't wait to see some threading action with reverse!!!!

[@FrancoCNC]

Thanks. All I need to do is wire up the relay(s) that will flip/flop the motor polarity. That will be my next project.

[@jasondevault5066]

I need this. I have the sherline 4400, looks like the same motor.

[@s.scottdonelson1118]

Thanks for the great videos....I have a question ...Is it possible by using the kbsi-240 and kbic-240 to control the spindle in both forward and reverse directions using the centroid acorn and relay board?

[@wade-airdog7730]

Thanks for the phenomenal videos Franco. I saw your previous video on using the KBSI-240D board on the PM-25MV. To clarify, does the PM-25MV also require the KBLC-240DS DC motor controller for spindle speed & direction control via Acorn? Or would the PM-25MV be wired up as per the diagram in your last video where only the KBSI-240D was shown? I'm a little confused on what configuration would necessitate using the KBLC-240DS and where it's not needed.... I guess I'm looking to confirm whether you're now saying that it should be used anytime a DC motor is in use?

[@FrancoCNC]

Hi. For the PM25MV you should only need the KBSI-240D signal isolation board. It isolates the Acorn and scales the 10V down to 5V suitable for controlling the PM25MV motor controller. I just placed an updated schematic for the PM25MV in the dropbox folder. www.dropbox.com/s/o7y9prakpibc8pp/PM25-Schematics2.pdf?dl=0

[@deondaugherty6723]

Hi Franco, Great Videos. Just converted my lathe with the encoder. All is working good. Did you ever get the lathe to turn in reverse? If so could you provide a video or the wiring diagram? Keep up the good work.

[@FrancoCNC]

Hi. I think this will get you pretty close. kzbin.info/www/bejne/bHLFmpKnfZand9U

[@deondaugherty6723]

Hi Again. That video shows for the mill with a different dc motor control board than The Sherline lathe dc motor control board is different?

[@reddog6248]

If you were using this setup on a larger Lathe ie CSS but without steppers on the closs slide (manual op) what or how would you provide feeback to maintain constant spindle speed

[@FrancoCNC]

Hi. The acorn product does't have any way of doing that. I can read a spindle encoder and control a spindle VFD. It will adjust axis movement to compensate for the true spindle rotation. But, it doesn't have any way to read an axis encoder and then adjust the spindle to match.

[@markdavis5255]

How did you hook the relay to turn the spindle on and off on your KBLC-240DS Controller?

[@gordonjones1516]

His setup really just takes over the potentiomter in the controller. When the Acorn is powered up it controls the spindle speed. If you power off the Acorn the spindle will crank to max. I just make sure to turn off the controller before I power off the Acorn. You could tie the power line of the spindle into a relay on the acorn if you just want on/off control.

[@Beechdrvr]

Great job! Quick question. I understand that the isolator will take the 10V from Acorn and interpolate it for a 5V output to a speed controller like on my PM25. My question is, what benefit is the KB board over a VFD that takes 10V in and directly controls the motor? Is it purely cost? Or some functionality? Again great job. Your helping me with my conversion.

[@FrancoCNC]

Great question. A VFD is designed to work with a three phase AC motor. Most of these small mills/lathes are equipped with a DC motor. Therefore, in order to use the existing DC motor and driver, you need to use the signal isolation board. Or, you could swap out the motor and the electronics for an AC motor and VFD but that can be tricky. It's hard to find small three phase AC motors.

[@Beechdrvr]

Franco thanks! Had no idea they were 3ph specific. Guess I’ll be getting the board then. Keep up the great work.

[@unionse7en]

@@Beechdrvr VFD stands for Variable FREQUENCY Drive...it varies the frequency to control the speed....DC motors have no phases to control the frequency of.

[@michaelskoblin2315]

In your opinion, do you think it would work on my PM30-MV that has the 220Volt 2Hp Brushless DC motor? I'm pretty sure that it would because I measured the voltage across the speed potentiometer of the stock brushless drive at 5.0 volts, and it is a linear pot. I currently am using ACORN to turn the spindle on and off, but I really would like to control the RPM and Direction with G-codes.

[@FrancoCNC]

Hi. I think it will. Check out this video: kzbin.info/www/bejne/Y5mXnGBvptGHftE A nice gentleman sent me the wiring diagram for his PM-25MV which should have the same spindle drive as your machine. I think should be pretty simple to control the spindle RPM once you have the voltage isolation board.

[@ponydown418]

Very cool. I'm still learning and learning for when I do my conversion. Is a encoder required for running that board for spindle control or is it just for reading the true spindle speed. I'm will be converting a pm25mv and I'm trying to get all my ducks in a row. Thanks again.

[@FrancoCNC]

Hi. You can control a spindle without the encoder. The only time you NEED an encoder is for threading and/or tapping.

[@ponydown418]

@@FrancoCNC thanks for the info Franco!

[@GypsyRewind]

...but why are you don't using pid-control ? it most be better presign, actualy

[@kenjames6172]

EACH ONE OF YOUR VIDEOS MOVE ME CLOSER TO COMPLETING MY SYSTEM. CAN YOU FURNISH ME WITH A DRAWING OF THE INCODER BRACKET AND ONE OF YOUR PRINTED COVER.