Shielding wires

LarryGZone
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Joined: Thu Dec 18, 2014 6:08 pm
Location: NE Ohio

Re: Shielding wires

Post by LarryGZone » Sat May 23, 2015 12:42 am

A related question on my newly-assembled SO3. I am chasing noise from the Dewalt spindle. The connection from computer to controller is randomly dropped. The Motion Control software goes back to "Connect Cutter" screen in the middle of a job. At times just 10 minutes into the job, other times an hour. I added several ferrite beads to the USB cable and to the power cord on the Dewalt. I also changed out to a shorter USB cable, and routed it by itself on the left side (from the back) away from all other cables. It appears that the noise is being picked up by the USB cable AND the Z stepper cable. It appears OK for now; but I hate intermittent problems. My next step is to locate a well shielded USB cable that is a practical (3 meter) length for my setup.

Anyone else chasing noise from the Dewalt?
Stock SO3 SN #024

rtlflatt
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Joined: Sun Jan 18, 2015 2:11 am
Location: Bay Area, CA

Re: Shielding wires

Post by rtlflatt » Sat May 23, 2015 1:26 am

check your power settings on your computer. maybe power saving mode is shutting on usb ports after a while? and what makes you think its the router and not steppers? can you run jobs all way thru with router off but not with router on?
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LarryGZone
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Joined: Thu Dec 18, 2014 6:08 pm
Location: NE Ohio

Re: Shielding wires

Post by LarryGZone » Sat May 23, 2015 2:02 am

Hi rtlflatt. Yep, if I run the job with the router off all is well.

Computer is not in power save mode, I did check that. It did make two successful runs with router powered on using a really short USB cable routed on the opposite side.
Stock SO3 SN #024

lildave
Posts: 15
Joined: Sat Sep 06, 2014 7:16 pm

Re: Shielding wires

Post by lildave » Sat May 23, 2015 3:17 am

Mine was getting ground noise cause I had my grbl mounted to my machine. Try bonding you machine to your c omputer.

LTEPM
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Location: no where near the end of the rainbow

Re: Shielding wires

Post by LTEPM » Sat May 23, 2015 4:30 am

Have you rotated the router to isolate the 120VAC cord from the Z axis and X axis? Try not to run parallel to the Y axis for troubleshooting.

Couple of ideas to try:
Bonding strap to Z carriage to X carriage, X carriage to controller cover.

Ferrite cores over stepper motor wires

Try to route your power cord 90 degrees to the stepper motor wires to minimize coupling.

Try another USB cable with ferrite cores.

If you suspect it from the Z axis, it may be on both Z and X axis.

rtlflatt
Posts: 178
Joined: Sun Jan 18, 2015 2:11 am
Location: Bay Area, CA

Re: Shielding wires

Post by rtlflatt » Sat May 23, 2015 4:32 am

is your router connected to controller board with superpid or a relay to turn on/off or is just "dumb" and manually switched on?
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LarryGZone
Posts: 17
Joined: Thu Dec 18, 2014 6:08 pm
Location: NE Ohio

Re: Shielding wires

Post by LarryGZone » Sat May 23, 2015 12:01 pm

Thanks for all of the ideas!

@rtlflatt for now I have a "dumb" router; just plugged directly into AC outlet.

I am going to take a shotgun approach since I believe that the noise is being induced at multiple points. Per the suggestions from replies:
- Rotate the router to better isolate the router AC cord
-Grounding strap to all major components to make sure a good common ground is established (I think I have some copper braid laying around somewhere)
-Ferrite beads on the stepper motor lines

Just for kicks I will see if my Fluke can detect AC noise on the RMS setting and take some before and after readings. Maybe loosely couple to the USB cable and the stepper cables and see what it shows.

I will post results in a couple of days.

Now I know why some folks invest in DC spindles. But I really like the power the Dewalt provides, and it is fairly quiet.

-Larry G
Stock SO3 SN #024

newtothis
Posts: 125
Joined: Wed Feb 04, 2015 6:10 pm
Location: North Suburbs of Chicago

Re: Shielding wires

Post by newtothis » Sat May 23, 2015 2:45 pm

What type of USB connection port is used on the Carbide Board? Is it for the more common flat USB male end or one of those "square" male connectors?

Thinking of getting a high quality USB cable with a ferrite bead and most I can find have a flat common USB on one end and the "square-ish" male connector on the other end.

Edit; realized I did not use the technical terms. USB A - flat common. USB B- "square-ish" connector.
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LarryGZone
Posts: 17
Joined: Thu Dec 18, 2014 6:08 pm
Location: NE Ohio

Re: Shielding wires

Post by LarryGZone » Sat May 23, 2015 8:47 pm

Hey NewToThis, I knew exactly what you meant by squarish. Yes, it is that type, type B (not mini B).
Stock SO3 SN #024

LarryGZone
Posts: 17
Joined: Thu Dec 18, 2014 6:08 pm
Location: NE Ohio

Re: Shielding wires

Post by LarryGZone » Mon May 25, 2015 11:49 pm

Well, the problem is not shielding related. I have experienced the machine resetting even with the spindle powered off. At random times it happens even just at rest (no job running). I thought it was disconnecting the USB connection to the PC, but I noticed the Z motor jumps when the failure happens. The board is resetting randomly; not sure if it is a power supply problem or control board problem. But I am now convinced it is not a shielding issued. Now I need to determine if it is the power supply at fault, or the control board.
Stock SO3 SN #024

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