Page 1 of 5

So I bought a unused/used "buildyourcnc"

Posted: Sun Oct 31, 2021 3:49 pm
by metalman2
Yes I'm new to building. Plenty of CNC programming and operation experience but new to this side of it. Was recommended and just purchased the Acorn control but have not installed it yet. I've been looking over this forum and have yet to find a definite answer to my first of many questions I'm sure. This thing I've purchased has CW230 stepper drives with nema 23 stepper motors. I've read conflicting posts on whether I need to add a breakout board or just wire directly to the Acorn. I'd like to get started on the hookup while I'm waiting on the new CNCPC to arrive. Can someone point me in the right direction. Thanks, Steve

Re: So I bought a unused/used "buildyourcnc"

Posted: Sun Oct 31, 2021 4:34 pm
by Upnorth
Depends what you mean by a breakout board. You wont need one like what you would need for a mach 3 system. The acorn has most of what you need already set up for easy wiring If you are planning on running stepper motor drives you should get what is called an DB25 breakout board to make wiring easier. Good news is that it will only cost about $10.

Re: So I bought a unused/used "buildyourcnc"

Posted: Sun Oct 31, 2021 4:40 pm
by metalman2
I'll look into that. This project came my way with the previous owner planning on a mach 3 set-up I believe. Thanks

Re: So I bought a unused/used "buildyourcnc"

Posted: Sun Oct 31, 2021 4:57 pm
by metalman2
Where would I look for the wiring diagram for a db25 board for my drivers?

Re: So I bought a unused/used "buildyourcnc"

Posted: Mon Nov 01, 2021 1:16 pm
by Richards
The CW230 stepper drives are limited to 50kHz. A low cost replacement would be something like the DM542.

DB-25 breakout boards can be found on Amazon or EBay. I'm including a photo of two that I use. The larger board costs about $6-7 and the smaller board costs about $10. It comes with a hood that I don't use. The pins on the break-out-boards are numbered. You can use Centroidcnc drawing S14976.DWG as reference.
IMG_1659.jpg

Re: So I bought a unused/used "buildyourcnc"

Posted: Mon Nov 01, 2021 5:47 pm
by metalman2
I appreciate the info. As I stated I'm really green to the electronic side of CNC's and am hoping to learn a thing or two as I go. What does the 50khz limitation affect?

Re: So I bought a unused/used "buildyourcnc"

Posted: Tue Nov 02, 2021 12:52 pm
by Richards
50kHz limits the maximum speed of each axis. You set the speed using Wizard. I'm not at my test bench right now, but I think that 100 kHz, 200 kHz, and 400 kHz are the choices. I believe that you can set lower speeds by editing the PLC parameter table.

We all like to reuse parts and pieces to save a little money. I do it all the time; however, when new stepper drives are available for about $30 each, I would suggest thinking about replacing those drives. Those $30 drives handle much higher pulse rates. They are rated for 50V at up to 4.2A.

You didn't give us the model number of your NEMA 23 steppers. I like to use motors with low inductance (1.5mH to 3 mH). I also make sure that the motors have adequate torque to do the job. On my little Taig, 100 oz-in motors work fine. Those little motors would be a very poor match if I mounted them on a larger mill.

Re: So I bought a unused/used "buildyourcnc"

Posted: Tue Nov 02, 2021 6:23 pm
by metalman2
I wasn't given much documentation with this purchase. The motors just have a "buildyourcnc" part# and the only cross reference I found on the web was a 60bygh303-13 and that was also one of the spec sheets that came with it. I'm not opposed to upgrading drives and such, I just have concerns that I don't have enough knowledge and experience to get this thing running. I would like to try and do a as is approach and go from there but if what I have is just going to make it more difficult I'll upgrade.
Another question I have is why don't they want you to use a laptop to drive the acorn? Thanks for the help...

Re: So I bought a unused/used "buildyourcnc"

Posted: Wed Nov 03, 2021 6:23 am
by Richards
Laptop computers shut down services essential to running a reliable CNC program to conserve their battery power.

Building a basic Acorn based controller is simple. Forget about all the bells and whistles that are mentioned on the forum. Start with the most basic system that will do the job. On my Taig, I have three stepper motors. Period. I don't use limit or homing switches. I don't use the Acorn to control the mill's spindle motor. I could have easily used the components that came with the Acorn and only added a case, three DM-542 stepper drivers, three Oriental Motor NEMA 23 steppers (used motors that were removed from other projects), a 48VDC power supply for the steppers, a NUC i3 computer, a terminal, keyboard and mouse. That's it. I could have used almost any used Windows 10 desktop computer instead of using a NUC.

I mount a raw piece of aluminum in the Taig's vise, pick a point on the aluminum as my 0,0,0 point and then start running the job. Nothing could be simpler. I run almost 100% prototype parts, i.e., one-of-a-kind. If I were running production, I would add homing sensors and some accurate/repeatable work holding jigs, but I don't run production so I don't need to worry about making my Acorn based system complicated.

Re: So I bought a unused/used "buildyourcnc"

Posted: Wed Nov 03, 2021 8:39 am
by metalman2
Well that gives me a little hope!! Thanks