New Build, Ziggy's Onefinity Modification

[Ziggy]

Greetings.

I am upgrading the controller on my Onefinity Woodworker.

https://www.onefinitycnc.com

I have a question about connecting the com wire from the E-Stop Switch and the VFD.

Both show going to the COM pin on the power connector.

Would it be OK to connect them to the COM ports on the other side of the board (Yellow Arrows) rather than the power connector (Blue Arrow)?

I checked with a multi meter and they appear to ohm out as a short.

Please ignore the messy wiring. I am in the process of sorting that out.

Thanks!

[Centroid_Tech2]

Yes, those connections points are basically just like connecting to the power connector.
All "COM" points on the Acorn headers are directly connected together.

[Ziggy]

Thanks! I am just now getting back to this. Sigh... it has been a crazy work week.

I very much appreciate the answer.

[Ziggy]

I am getting nearer to completing my upgrade. I finally got the Acorn, driver, power supplies etc installed in a aluminum box.

I am using the Gecko G540 Driver connected via 25 pin ribbon cable.
I am using IGUS Chainflex shielded cable. (Shield connected to earth ground.)
I have a Meanwell 36V PS powering the G540.
I am using the stock Nema 23 2.8A motors. (With 2.8K resistor)
https://www.omc-stepperonline.com/nema- ... hs22-2804s

Other than the bench test and a very quick motor test, this past weekend is my first time connecting it to my CNC.

When i first tried it I noticed the motors "Hissing." Everything seemed to work OK but they were making a hissing noise. I did a little reading and I saw several posts about this on a few forums. The most resounding conclusion is that the hissing isn't a big deal but is quite annoying.

Some people suggested connecting a large (ish) capacitor across the output of the G540 power supply. I spoke with Gecko and they reccomended 20,000uF!!! I had already purchased a 6,800uF so I went with that.

I was also hoping that having my controller and driver in an isolated box with grounded shielding would help.

No luck. The darn thing still hisses.

The original Buildbotics controller didn't hiss. I have no idea what kind of driver it uses. All I know is that it also uses a 36V Meanwell power supply and is using a Raspberry Pi for the processing.

Has anyone else run into this?

[cnckeith]

always a good reference. https://www.geckodrive.com/support/step-motor-basics

the G540 was great in its day, now there are much better and affordable choices out there for smooth quiet motion.

[ShawnM]

I agree, the G540 should be rendered obsolete. Did you tune the G540 for your motors?
https://www.geckodrive.com/support/g540 ... and-tuning

[Ziggy]

the G540 was great in its day, now there are much better and affordable choices out there for smooth quiet motion.

I agree, the G540 should be rendered obsolete.

Thank you for the replies. I do appreciate it.

But I have to tell you, that is quite disheartening to read. I thought I did my research. Someone who knows way more about CNC than I do recommended the Acorn/G540 combo. I checked the website and there were G540 diagrams…at the top of the page as well. Even MartysCNCGarage featured a G540. So I just bought this thing brand new.

Sigh… No one ever said that the CNC learning curve wasn’t steep.

So what is the primary difference between what I have and something that is newer?

It has me wondering, would a newer style driver allow stall homing? I assumed that the Acorn wasn’t able to achieve stall homing because of a lack of current feedback from the driver. (Just a guess on my part.) Would a newer style driver allow for stall homing?

My original controller (Buildbotics) had stall homing and I really appreciated not having to have limit switches. In fact, with my limited CNC experience, the BB controller software is all I really know. It seemed very simple and easy to use. My only issue is that it would convert arcs and circles to line segments. This could be adjusted but users found issues with missed steps when adjusted to the point that the arcs were smooth. The general consensus was that the Raspberry Pi wasn’t powerful enough. This was my only reason for switching to Acorn.

With only having a few hours per week to do anything, it took me about two years to build this -my first- CNC. It took one real project to see a curve that wasn’t really a curve. Now I am retrofitting a new controller and evidently I just bought a brand new Windows 98 system complete with floppy drives.

If a new driver would allow for stall homing I might consider it…Or maybe there is some other compelling reason. I will only be cutting wood and maybe occasionally thin aluminum. Maybe I could sell the G540… I don’t know. I am going broke with this project.

(Or maybe there is some inherent issue with stall homing and that is why it isn’t used??)


----

Ahh!! Tuning! I did try the tuning when I was bench testing the G540. It made no difference then. But Now that I have everything grounded and have a much more robust filtering system on the PS it might make a difference.

Thanks for the suggestion!

[cnckeith]

nothing wrong with G540, its just 20 year old design. new drivers are more powerful, smoother and quieter. run with what you got and upgrade at some point when you want better performance out of the machine.

[Ziggy]

Thanks.... I just hate that I am discovering this now. I swear I called myself looking. I couldn't have imagined that I would be buying such an old design brand new. That being said, they still sell Simpson multimeters brand new.

There is just so much information out there that it is sometimes hard to find the nugget you need when you need it.

I really do appreciate the answers here.

[Ziggy]

Oh... Do you know if there is any way the Acorn board can be compatible with stall homing?

Also.... before I go down a wrong path... again...

On my BB controller I could connect to a port and output 3.3V DC levels. I would turn these on with "M" Gcode. I connected these to relay boards. Through the relays I ran 120V AC to switch on contactors. I had my router and vacuum running off of these contactors. So I could use Gcode to turn the router and vacuum on and off.

I have the relay board for the Acorn mounted in my controller. Three of the relays will be used for the VFD. My plan was to use two of the remaining relays to turn on the contactors. Not wild about running 120V AC through the Acorn relays but it is very low current.

Before I go through all of that... does the Acorn have a way to simply output a DC signal via G-code. I suppose I could get a regulator and run DC from the power supply to the relays and avoid having to use 120V... But I was wondering if there was another way.

BTW... I just now found the software manual... I haven't had a chance to read through it yet. It is quite long and time is quite short... especially at my age. <grin>