GRBL Error: Serial Port: ResourceError

Interesting to say the least @mpfreivald. Great observational details can often make/break debugging. I’d be scoping out the stepper lines and jogging around to said “position of doom” to see if there was something obvious… luckily, not a lick of connectivity or noise problems so far with my limited XXL operations (knock on MDF).

Curious if you guys have got anywhere? I did try re-positioning my cutter changing the Z position and still had the error.

I stepped away from the machine for a couple of days out of frustration. Hoping if I decide to stay with the Nomad a fresh attitude will help me find the issue when I return to it.

Unfortunately, I had this problem happened in the middle or the run.

I hope there is a solution for this problem

I have the same issue. Any solution out there?

Email so we can open a ticket and get it taken care of.


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Same problem here in New Mexico. I cannot shut down the dewalt router without getting the error. Sometimes get this during a job. Real pain because we are a production shop.
Emailed Jorge again today. Maybe a new board?

I’ve played around a bit with a multi-board setup (v2,2 & v2.3 CM boards) as I’m running multiple CAM standards (GRBL & ESTL). Since I’m using a “more prone to dropout” v2.2 CM board, I wanted to identify and mitigate the sources for USB dropouts.

In my experimentation with wire proximity, I can guarantee a dropout of comms if the Dewalt power cord is anywhere near any DC wiring (servo or limit switches) or gantry framing. Physically isolating DC and AC wiring will help mitigate the back EMF noise, as will grounding the machine and powering your router from another AC branch.

I have also run ferrite cores on all the wiring. With these steps I’m running this older v2.2 with extreme reliability.



Thanks, Jim.
William emailed immediately this morning… Sending a new board.
Ferrite cores… will get some.
Already using two AC outlets.
Dewalt power cord is isolated.
I do not know how to properly ground the frame. Any suggestions welcome.
Thanks, Jim.

The big thing in grounding the frame is to ensure a star topology to the central grounding point, and to avoid any loops.

I clicked the link. Whoo-boy. Is there a dummy’s guide to grounding?

Maybe I can run a copper wire from the SO3 frame to the ground connector inside my electrical junction box?


Where are you located? USA, your shop should be wired with a 3 wire system. Green is ground, so you can use that ground.

Problem seems to be solved.
We received a new control board (version 2.4d) yesterday.
No problems showed up after installation of the new board.

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Your problem is solved… This problem is plaguing me. I’ve tried grounding all the components together, using a surge protector, powered usb port, shielded usb cable. I have ruined so much material with the machine randomly stopping in the middle of a job, even if the job is only a couple minutes long.

My controller version is 2.2, machine number 688. I feel like I’m being punished by having bought an early machine (pay to upgrade the z plate, pay to get wider belts, pay to get homing switches) I really want this machine to work well, but every time I have tried to use it since I bought it, its been nothing but frustration.

I sent an email to support but they just asked me to do the same things that are already listed in this thread and the links given earlier. I’m

Have you updated your ticket with support and informed them you tried everything in the links? its also not mandatory to pay for any upgrades,you do have a choice.

Please re-read your e-mail from support.

As I understood it when it was typed up, you were asked to confirm that you had tried the things in that list which were reasonable for you to have tried, and that if that were the case, we’d have someone contact you and work things out.

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I have now, I guess my email was still open as I never hit send. I will admit I am impressed to get support on the weekend :slight_smile:


Just wanted to update this post that support helped me get things straightened out. Not up and running again, but I think I’m pretty close.


this url ( ) is coming up as 404 not found.

i am running into a similar issue, can’t connect. i ran the hello world just fine last weekend - now i’m trying to get some work done and i’m getting the same error.

We’ve been revamping our site. That is instead at:

I suspect you have a problem specifically w/ Carbide Motion or permissions if Chilipeppr works — hopefully we can have a developer contact you about this next week — until then, my suggestion would be to use Universal G-code Sender:

or bCNC or some other comm / control app.

i tried UGS it connected but as noted wouldn’t do anything beyond that.

i’ll look at bCNC.