SO3 Upgrade: Serial Port Unknown

CNC Machines Shapeoko
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Hello,

First I want to say thank you to Carbide 3d over the years with offering an affordable CNC machine that has allowed me to start a business, quit my full time job and now begin scaling up to a production shop. My business has grown at over 100% per year for the last 3 years since it’s inception which is good fun.

I have over time been upgrading my SO3 to meet my increasing demands. There have been months where I have ran it for nearly 40 hours per week and it has proven to be a workhorse. The vast majority of my machining is carbon fiber as well as cutting out 1/8 inch aluminum plates.

I have contemplated purchasing a CNC Router Parts Benchtop Pro for awhile now as moving forward I am going to start machining aluminum molds for pre-preg carbon fiber among other things. This will require more rigidity and precision. I decided since I was already pretty heavily invested into the SO3 and I’m familiar with it that I’d just try to upgrade what I have.

So what I’ve done in this series of upgrades is change the X travel to use a linear rail, upgrade to HDZ and a 2.2kw water cooled spindle.

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I wanted to get everything installed and confirm that it runs properly before finding a permanent place for everything like the VFD, water pump etc.

Before booting up the spindle, the machine can rapid and jog in all directions flawlessly.

The issue: Once the spindle is turned on GRBL outputs “Error (x) GRBL ERROR: Serial Port: Unkown Error” and the machine becomes disconnected. The issue is directly related to the spindle turning on. The VFD can be powered on and the machine will move perfectly fine, but repeatably once the spindle is turned on the machine disconnects. I put an “x” on the Error number as I have gotten a (3, 31, 34, 35, 39 &41) and those are just the ones I’ve written down.

I’ve had issues like this with my SO3 and SO3 XL (seems to be a pattern) but usually have been able to solve it by making sure there are are no other cables touching the power cable or USB cable since as far as I know the EMI messes with the controller or something. I’ve had this problem before on this exact machine and solved it with some combination of moving around power cords and USB cables until it was happy again.

It seems no combination of moving the cables will resolve this. The power cable and USB cable is not touching anything else. I even moved the spindle cable going to the VFD out to the front of the machine to see to make sure it is not touching anything.

I then tried to have the CNC off while the spindle was on and running. Then power up the machine, home it and run a proven program. It worked for about 4 minutes until the issue came up again. I know this is a proven program as I’ve ran it nearly 100 times before. I took the endmill out and ran the program with the spindle off and it ran perfectly fine.

I have grounded the machine, The threaded table is bolted to the countertop with M6 screws and the screws are connected to a earth wire going to an outlet.

The only thing I can think of to try next is to change the cord going from the spindle to the VFD. It came with a 12/3 cord, so no grounding wire. I could get a 12/4 cord and use the grounding wire and see if that makes any difference?

Any help/advice would be appreciated as I’m dangerously close to just buying the CNC Router Parts Benchtop Pro.

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Could it be EMI from your (what looks to be) unshielded cable from your VFD to your spindle?

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Also, the controller I’m running is v2.4c with a fresh install of the latest CM V4 Build 417

@madhatter I’m not sure as it is the cable that came with the spindle/vfd kit. It’s double insulated with a drain wire, but didn’t have a foiled shield. Only thing I know to try still is to get a 12/4 that includes a grounding wire.

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First off, I don’t have a SO3, but I’ve had VFDs powering numerous machines over the years.

In m opinion, it most probably isn’t a SO3 issue, it is the VFD you are using. Try finding shielded wire for the run from the VFD to the router. And if possible any wiring from VFD to controls.
I had a VFD in the past emit so much interference, I couldn’t play a radio in the same building.

All US VFD manufacturers Suggest using shielded wiring from VFD to router and on wiring to controls.

Hope this helps

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Oh, okay. It just looked a bit small diameter for VFD cable.

This is the VFD wire I am using and I have had no EMI issues from the VFD. I do occasionally have disconnects in the winter when the air is dry and my ground wire comes off the flexible dust hose though.

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Thank you very much, just ordered this cable. Fingers crossed it works!

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Also, you may want to consider updating to a 2.4e controller — I believe it has improved EMI filtering over 2.4d — drop us a line at support@carbide3d.com and we’ll work that out.

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Thank you @WillAdams just sent an email over to support. I have the 2.4c which is even older I suspect :smiley:

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When it arrives, I suggest installing it per this document [PDF Warning].

And instead of using the super heavy duty shrink wrap, I used the “F4” self fusing silicone tape from Amazon for all my wire taping needs. It fuses to itself making a single homogeneous layer of rubber. I have both the black and orange rolls. When I am layering the tape, it helps to alternate colors to see how the overlap is between each successive layer.

Also, the wire is thick enough that I had to cut away the clamping collar on the connector backshell at the spindle and have the wire just get taped in with the F4 tape. I also used the F4 tape to make a flexible wrap to hold the water lines and VFD cable together. The F4 tape sticks to itself, but not other stuff.

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Look at the size of that cable!

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Thank you very much for your help @MadHatter ! So you wrapped the hole cable in that F4 tape or just the ends of it?

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Just the ends. If you read through the Belden document it tells you to shrink wrap wires and use electrical tape on the wires during the hookup process. I used the F4 tape instead of the shrink wrap and electrical tape. The F4 tape is more flexible, doesn’t leave an adhesive residue like vinyl electrical tape, doesn’t get old and brittle and crack away, and can easily be cut away if need be. I really prefer it over vinyl electrical tape.

But the short answer is - I did not wrap the entire cable, just the ends where needed when terminating it.

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one thing in these forums that comes up is that grounding the spindle itself helps, and that some spindles are complicated to ground somehow

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Definitely sounds like it could be a vfd issue. Have you tried playing around with the settings like the carrier frequency?

Easy test with a meter to check continuity with the ground to the body and yeah, definitely run another wire and ground to the vfd.

I for one am not convinced you need a specialized vfd cable, mine was “repurposed” from a regular extension cord with added ground. Works great

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@zhodg77 , I may have missed it in the posts above but did you double-check whether the body of your spindle was actually connected to the GND wire at the aviation connector level ? Many chinese spindles seem to NOT have GND connected when they arrivet, and folks often have to open the rear of the spindle and solder a grounding wire in there from the GND pin to the body of the spindle.
You probably did already, but in case you didn’t, check continuity between GND at your VFD’s motor connectors, and the body of the spindle.

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