Losing Connection in Middle of Project

Talk about all things CNC
Post Reply
Bangalore
Posts: 41
Joined: Mon Apr 27, 2015 10:52 pm

Losing Connection in Middle of Project

Post by Bangalore » Tue Aug 11, 2015 3:25 am

Ok. So, I've racked my brain, dug through the forums and tried everything I could. I spoke with Carbide this morning and it looks like they will be sending me a new board. Here's what's happening.

Spindle (Dewalt 611) is on its own breaker; power lines are run off of the right side.
Laptop is running off of battery only. I've also tried with the laptop plugged in.
Shapeoko is on it's own breaker, separate from the Spindle.

USB and power are running out of the left, but are not crossing over stepper wires at all. USB runs out to the top, power to the bottom.
USB also has ferrite torus (choke core). (I've also tried it without).

Shapoko connects, starts, jogs, etc. Then, on occasion, apparently at random, loses connection to the computer. It freezes in place and does not respond to commands. The only solution is to power down the board, restart Carbide Motion (Same with UGS), thus losing zero, and start over. This happens at various times and places with multiple codes. It even freezes while jogging the machine. As a matter of fact, it took nearly a half hour just to get it connected to run a log to send grbl setup notes ($$) when I emailed about the problem.
This happens with or without the following plugged in or operating: shop vac, spindle, laptop, garage door opener (yep, I even checked that).

So, it seems that I have a bad board, and thankfully it looks like it will be replaced. The folks at Carbide were super helpful when I called. However, this is my only time off before going back to work with no breaks after next week until the end of the year. This was supposed to be "the week of Shapeoko" at my house, kids gone, wife at work, me at home building whatever I could imagine.

Has anyone else had or more specifically solved this problem? Any tips while I await my new board?

I know some of this has been discussed elsewhere, but I've honestly read everything I could find and tried it all.
http://www.BillySalyers.com
Shapeoko 3 #585 Couple of Tweaks

JeromyReno
Posts: 225
Joined: Mon May 04, 2015 11:28 pm

Re: Losing Connection in Middle of Project

Post by JeromyReno » Tue Aug 11, 2015 3:20 pm

mine did basically that yesterday for the first time is a long time. after I started using two circuits to separate any fly back emf from the coils in the router and the power to the machine/computer I thought I was fixed for good. if you have homing switches you should be able to fire it back up and start over and save the work piece.

Bangalore
Posts: 41
Joined: Mon Apr 27, 2015 10:52 pm

Re: Losing Connection in Middle of Project

Post by Bangalore » Tue Aug 11, 2015 3:26 pm

I'm on two separate circuits already. Doesn't seem to help. This happens even when the spindle isn't plugged in, when its just the Shapeoko itself. Unfortunately, homing switches are not yet installed. Maybe today is a Radio Shack day.
http://www.BillySalyers.com
Shapeoko 3 #585 Couple of Tweaks

MikeD
Posts: 25
Joined: Thu Sep 10, 2015 2:50 pm

Re: Losing Connection in Middle of Project

Post by MikeD » Sun Sep 27, 2015 3:24 pm

Mine has this issue as well. I'm working on isolating the issue, but it seems power related. Mine will disconnect when i turn off the router, turn on the band saw, or change speeds on the router quickly. I'm thinking that putting the Shapeoko on a battery UPS will fix it..... I'll keep y'all posted on how it goes.
Shapeoko 3 #0773

WillAdams
Posts: 8489
Joined: Mon Apr 09, 2012 6:11 pm
Location: Pennsylvania --- south of the Turnpike, East of US-15
Contact:

Re: Losing Connection in Middle of Project

Post by WillAdams » Sun Sep 27, 2015 3:52 pm

Random disconnects are usually some high draw device coming on-line, a refrigerator compressor or air conditioning units are typical culprits.
Shapeoko 3XL #0006 w/Makita RT0701 Router w/0.125″ and ¼″ Elaire precision collets
Nomad 883 Pro #596 (bamboo)

TomDChi
Posts: 184
Joined: Wed Mar 18, 2015 2:36 pm

Re: Losing Connection in Middle of Project

Post by TomDChi » Mon Sep 28, 2015 5:24 am

WillAdams wrote:Random disconnects are usually some high draw device coming on-line, a refrigerator compressor or air conditioning units are typical culprits.
I assume that's more likely coming through the AC to DC power converter that's plugged into the board, rather than through the computer that's connected to the USB cable, right? Even so, I'm surprised that the AC to DC converter isn't more effectively filtering that out, or we may be learning that the current design of the Carbide board is really sensitive. I only have an old school analog oscilloscope, but it would be interesting to see if anyone had a newer digtital o scope that can capture brief events to see what's happening to the DC being fed to the board when stuff like a clunky fridge or the AC kicks on. How bad could that DC noise/spike be?

cvoinescu
Posts: 4442
Joined: Thu Jul 19, 2012 6:50 pm
Location: Camberley, UK
Contact:

Re: Losing Connection in Middle of Project

Post by cvoinescu » Mon Sep 28, 2015 11:15 am

As I understand it, the problem is caused by the two ends of the USB cable briefly being at different potentials. For instance, if your fridge compressor turns off, it causes a burst of high-frequency noise. This propagates along the mains, and reaches both the PC and the machine. Both of them let some of this noise cross from mains into the DC side, as common-mode noise (both positive and negative terminals vary at the same time with respect to ground). This would be all fine if both the computer and the Shapeoko would let the exact same amount of noise go through; unfortunately, that's not the case. The USB cable is the most direct connection between the two, so the current that tries to equalize the potential travels through it. USB can take a certain (small) amount of common-mode noise, but more than that causes a communication error that it can not recover from.

Possible solutions follow from this understanding:
  • Do not have noise on the mains in the first place. Add ferrite cores on the power cords of noise-producing equipment (as close to it as possible).
  • Use a different circuit from the noisy stuff. Plug both machine and PC in the same power strip, but router elsewhere.
  • Stop the noise from reaching both the machine and the computer. Doing just one may make things worse, not better. Good EMI filters can do this. Computers already have half-decent ones, other power supplies should have them, but quality varies.
  • Provide a low-impedance path for the noise other than the USB cable. In other words, connect the grounds of the PC and the machine together with a short, stout cable.
  • Desktop PCs have the signal ground connected to the protective (earth) ground. The Shapeoko probably doesn't. In my experience, it made a small but noticeable difference to make the same connection (negative of the supply to earth ground) on the machine side. This may change the electrical safety class of the machine (so it would be regulated differently), and it may make things worse rather than better, especially when the computer is a laptop.
  • If your country uses reversible plugs (e.g. Germany, Italy), unplug the machine and turn the plug around. (Unscientific, but sometimes works.)
  • Use a good-quality, fully screened USB cable, as short as feasible.
  • Add ferrite cores to the USB cable. These suppress common-mode high-frequency noise, and they can help a lot.
  • Finally, galvanically isolate the machine end of the USB cable. This was the only thing that worked for me, and I could undo all the other counter-measures, and I could still not cause disconnections anymore, even intentionally.
Proud owner of ShapeOko #709, eShapeOko #0, and of store.amberspyglass.co.uk

AnonymousPerson
Posts: 758
Joined: Sun Apr 26, 2015 1:16 pm
Location: 3753 Cruithne

Re: Losing Connection in Middle of Project

Post by AnonymousPerson » Mon Sep 28, 2015 11:46 am

cvoinescu wrote:
  • Do not have noise on the mains in the first place. Add ferrite cores on the power cords of noise-producing equipment (as close to it as possible).
  • Add ferrite cores to the USB cable. These suppress common-mode high-frequency noise, and they can help a lot.
With ferrite cores, will any do, or do they need to be specially chosen to match the noise characteristics?

Asking because I was looking at ferrite cores recently to help reduce the RF noise caused by my GTX970 video card. It seemed like there are different ferrite cores designed to block different types of noise. (I picked a random selection... and the RF noise from the video card hasn't decreased yet. Still interested in a solution... :)).
Shapeoko 3 #516

cvoinescu
Posts: 4442
Joined: Thu Jul 19, 2012 6:50 pm
Location: Camberley, UK
Contact:

Re: Losing Connection in Middle of Project

Post by cvoinescu » Mon Sep 28, 2015 1:05 pm

AnonymousPerson wrote:With ferrite cores, will any do, or do they need to be specially chosen to match the noise characteristics?
For this, larger ones are generally better, and if you can wind the cord around a couple of times, you get better suppression (but there are limits to that).
AnonymousPerson wrote:Asking because I was looking at ferrite cores recently to help reduce the RF noise caused by my GTX970 video card.
How is that noise coupled, and where do you put the ferrite cores? If, for instance, the noise affects your sound card, there's not much you can do, because the source of noise is inside the computer case, and it's coupled through the PCIe slot, which you can't really block, through the power supply, which you can block to a small extent by putting a ferrite core on the auxiliary 12 V connector to the card, and radiated all over the inside of the case. If it's noise that affects something outside the PC, it's probably a little more tractable, but I don't know enough to give you good advice.
Proud owner of ShapeOko #709, eShapeOko #0, and of store.amberspyglass.co.uk

MikeD
Posts: 25
Joined: Thu Sep 10, 2015 2:50 pm

Re: Losing Connection in Middle of Project

Post by MikeD » Mon Sep 28, 2015 11:01 pm

So i went and bought this http://www.bestbuy.com/site/olstemplate ... finder.jsp

Didn't help at all..... so I guess galvanic isolation is the way to go. Gotta figure out what that means exactly and how to implement.

If i change the speed of the floor fan I loose connectivity. I was just running a part and about 10min into a program, my wife came in to see what i was doing and bumped the fan, lost connection... crap.
Shapeoko 3 #0773

Post Reply