# Opinion of someone wiser than myself?



## buildsbyboadie (Nov 29, 2021)

Hey guys.  So I bought a hurco cnc mill (big blue one for the 80s I believe) a few months back, and  it came with a centroid Dc3io & cpu10 retrofit haphazardly installed.  I was informed when I bought it that the guy wasn’t sure if it worked since it was his fathers, hence the attractive price tag.   As it turns out, I believe the cpu10 card is defective as it’s throwing a servo drive fault all of a sudden and I’ve done everything centroid and myself could think of to try to resolve the issue.

So I’m at the point where I need to make a decision on what to do to get this machine running. Option 1 is to send in the cpu10 card for an evaluation/repair, or option 2 is to update the controller with something a little newer and with something that definitely has more popularity online as far as forums, videos, and so on, which would be gecko drives with a pmdx plc and motion controller.

So basically I’m wondering if I can expect similar performance out of the gecko & pmdx option as I can out of the centroid system.  The gecko& pmdx option would still be cheaper, even building a controller from scratch, than it would be to fix the cpu 10 card.  But I already have the centroid system wired and installed on the machine.  Just because I’m sure someone will mention it, yes I would love to upgrade to the allin1 dc but I just can’t afford the 3000$ at the moment, that being said though, the price difference between my 2 options isn’t really a factor   So do u guys think there would be enough, if any, performance difference to justify the price and usability of the 2 systems ?  Idk if it makes a difference or not but I’m not a production shop or anything.  Just a kid that loves building cool stuff in his garage, but would also rather spend the few extra dollars and go with the better choice.  So if anyone has some insight, I’d love to hear what you guys think.  Thank you


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## JimDawson (Nov 29, 2021)

What motors & drives do you have on that machine?

Edit: I did a bit of research and it looks like the Gecko 320X drives would work.  You might concider the Centroid Acorn controller.


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## markba633csi (Nov 29, 2021)

That's what I was thinking too, if it's giving a servo drive fault, just replace the drive or get it repaired.
Can you interchange two drives on the machine to see if the problem follows the drive?
-Mark


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## buildsbyboadie (Nov 30, 2021)

The drive is integrated with the plc   According to centroid, it’s an error with the servodrive/plc communicating with the motion controller   The only problem I have with fixing it is it cost 175 per item just to be inspected.  So that’s 350$ just to tell me that there’s something wrong  then a minimum of another $375+ to repair, depending on what is actually damaged.    So it could potentially be 8-900$ to repair the part when I could replace it with a brand new one for 1000$   But for half of that I could get most of what I’d need for the pmdx/gecko build.   Other issues I have that I didn’t mention above is the software and os for that specific controller is a 10+ Y/o linux distro that is a pita to use    And as far as getting the acorn controller, acorn isn’t closed loop from my understanding and I have encoders on the servos so it would be a bit of disservice to not use them imo (like I said earlier, I’d rather spend the little bit extra cash and get all the bells and whistles).  But I appreciate the feedback. After all, I am somewhat familiar with the centroid software, and the control panel is already completely wired with the centroid system, so it would certainly be a lot less work to just plug and play the new board


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## JimDawson (Nov 30, 2021)

The Gecko 320X will only accept a step & direction input thus is a good match for the PMDX or Acorn.  The PMDX products are also open loop systems so no gain there over the Acorn.  Using the Gecko 320X drive, the loop would be closed at the drive, thus you can run with an open loop controller and still have the benefit of a closed loop.

I think what you are really wanting is an analog controlled system with the loop closed at the the motion controller, which I believe is what you have now.  Since you don't have the original analog velocity drives for the machine, this is going to be a bit tricky.  You would need either velocity or torque mode analog drives, similar to these https://teknic.com/files/product_info/E4-5_r1.3.pdf  About $335 each.

Then would need a motion controller that has analog command output capability.  This limits you to about 4 options in the hobby price range: Galil Motion Control Products, Dynomotion Kflop/Kanalog, Centroid All-in-One DC, or Mesa products.  Both the Centroid and Dynomotion come with the CNC software.  The Galil and Mesa products are compatible with Mach3/4 software.

My personal favorite are the Galil products, I use them on all of my machines.  I also wrote my own CNC software that I give away.  When purchased new the Galil products are crazy expensive (and worth it), but there are normally some really good deals to be had on them from eBay vendors.


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