Centroid Community CNC Support Forum

I've got a 2006 PRT Alpha 96 that I'd like to upgrade the control board on - primarily to get away from that shaky control software.

Here's a photo of the control box innards:


The control box contains four Vexta/Oriental Motor ASD30E-A-B1 closed loop drivers.

I don't have any issues with the machine performance, so I really don't have any desire to start swapping drivers and motors. (the motors on my machine are not the 7.4 geared motors that later tools have)

How feasible would it be to swap out *only* the V210 controller that's currently installed? I've got the pinout for the DC37 connector and the two ribbon cables that interface the controller to the large PCBs at the bottom of the control box. (the pinouts are available here: https://www.shopbottools.com/files/Shop ... ctions.pdf)

Assuming I had a suitable adapter framework that covered the I/O on the DC37 & ribbon headers, could the Acorn controller be a "drop in" replacement?

tnx!

g.

Contact Gary Cambell. He's helped a lot of guys upgrade their Shopbots by using an Acorn controller.

Gene...
In theory what you wish to do is possible, but in reality, very difficult for the inexperienced. Here are the reasons:

1) Without gear reduction you would have a 0.318.. turns ratio. Far below what is required for Centroid. That direct drive alpha was so bad that SB traded them out for gearmotors after realizing their mistake. You would have to add gear reduction. Currently SureGear N34 5:1 gearboxes are $471 each.

2) If you do add gearboxes, the OEM swing brackets are not strong enough to handle the torque nor the overhang weight of the gearbox & motor.

2) ShopBot used some wonky drive programming on those drives to try and get them running well. Plus, they used a "resolution multiplier", which was actually a resolution divider as is reduced resolution by a multiple of 4 during rapid moves. You would need to have the drives reprogrammed to be able to use them. ShopBot won't do it and they have the "magic encoder ring". You may be able to source drives with OEM programming on the web.

3) It would be a nightmare to try and run the IO and step/direction from the Acorn's DB25 thru that old IO board as many of ShopBots signals are inverted, i.e., ttl high (source), where acorns signals are ttl low (sink). You would have to design and build a "gender changer" for the signals. Plus those old components may not be up to handling data at modern speeds. That vintage signals were in the ~30khtz range and out current builds are using 200Khtz.

4) That hardware is at least 20 years old and is using 30 year old technology, getting it to marry up and work well with a modern controller would be difficult for the experienced. A never ending nightmare for the inexperienced.

5) Now you know the reasons that I started building replacement controllers in 2014. And why I have never looked back.

EDIT: P.S.: I have a spreadsheet with the crossover pinout from when I tried this years ago. Its yours if you want it.

Mr. Gary,

Nice...When you talk about inexperienced persons handling out-of-date data and software, I am keen! Not as keen as your shopbot lingo but nonetheless, I still try.

Seth

P.S. Keep up the good work, fellows/gals. I got me two boards (Acorns) and one is a full-fledge user already. Giving orders and commanding the scene!

I have a 2001 PRT which I wanted to upgrade a couple of years ago. If I was 10 or so years younger I would gotten a new machine.I am in over my head speaking of the electronics but I can speak to my experience with one of Gary’s systems built by Scott Worden. While not an Alpha with the closed loop motors, I wanted to save money and use the original Oriental motors with an Acorn box. It worked great and was a much smoother and better machine. After a year os so I had some driver problems and had Scott redo the controls and change out the motors and drivers with Leadshine. I regret not doing this at first. Besides the advantages of the Acorn and the geode the machine and the rotary axis are so much smoother, faster and reliable. I can cut at more than 360 ipm which is pretty amazing for a PRT. If you’re going to change to Acorn, listen to Gary and change it all out.

Well fork. Thanks for the info Gary!

I'm essentially a hobbyist user of the machine - I *might* have 200 hours on it since I bought it in 2006. (I was *super* annoyed that they came out with the PRS a couple of weeks after I took delivery of the machine...) My only real complaint is that horrible control software - it would be tolerable if it didn't fall over and die at a harsh look.

Do you still offer those turnkey control box/stepper combos? I thought I saw a link somewhere for it, but I can't seem to find it any longer.

Thanks again!

g.

Gene ...
Info is here: https://www.centroidcnc.com/shopbot_gcnc.html

I've reached out to Gary and I'm looking at some options. \o/

g.

@geneb whatever Gary tells you is the straight dope...he won't lead you wrong...the machine pictured at the link above is the one he retrofitted for me. Transformed is not too strong. Rezzurected might be more like it.