Communication issue? Grind noise, then position loss

[Brady Watson]

David,
Please check your dust hose ground one more time. The symptoms you list point at ungrounded high voltage static. You cannot use the same ground as the control box, as it may cause a ground loop issue. Below is the suggested 'tried & true' method of correctly grounding your dust collection system. Take NOTHING for granted...

First, verify ground between electrical system ground and your dust collector chassis. Put one probe of meter in ground in electrical outlet & other probe against a metal bolt, screw or lug on the DC chassis - preferably the exact location you plan on grounding the end of the bare copper wire. The spiral bound wire encapsulated in the hose is not suitable for grounding. It is there for physical support only. The ground must be a bare copper wire without exception. Doorbell wire stripped of insulation works perfectly.

Run the bare copper wire through the dust foot, connecting to the alligator clip, then through the entire length of hose, then go through the hose and tie off at the place where you checked continuity. You can tie a rag to the wire, fire up the DC and throttle it until it get close to the DC, before turning it off. Then test continuity between the copper wire and your electrical ground.

The high voltage generated by dust collection can, will & does overpower low voltage DC switches and sensors on the machine, that operate at 5vdc (USB, input switches) and 24vdc (prox switches). If you don't give the voltage a 'path of least resistance' via bare copper wire inside the hose that acts like an antenna to wick up the static - then, it will find it's own path, which will either be the X or Y Prox switch wires (long antenna) or USB cable (long antenna)...Prox switches that get 'stepped on' via high voltage result in false 'Limit Switch Hit' and 'Emergency Stop Hit' messages, interruptions in the communication stream or 'thuds & bumps' in movement are caused by the USB 5v cable getting 'stepped on'. If you have good Com speeds, and computer is good...you've got static issues.

For the heck of it...check it again. AND - also check that you have continuity between the dust foot clip and the dust collector. Wires CAN break!

I've seen it happen so many times that people think they are grounded, only to find they are not because of a broken wire, a corroded contact or other thing that doesn't work properly.

-B

[steve_g]

I recently discovered that the cable guy broke my clamp where my electric panel attaches to my ground rod outside... he just left it!

Steve

[Brett1970]

i could swear the grounding guide i found on here DOES tell you to go to the dust collector from the leg of your shopbot. Should i ground my dust collector directly the earth ground outside? It's only about 6 - 8 feet tops from my dust collector to my ground lug. I don't think this would cause a loop, unless it did throught the electrical ground coming from the plug to power the the dust collector motor. I removed my aligator clip and replaced it with an eyelet, and attached it to the dust boot at one of it's rivets. No chance of my wire being sucked through the dust collector.

[garyc]

David...
Attaching the ground wire to the dust foot mounting rivets will allow static to dischage directly to the machine. Brady gives very clear instructions above. It will be in your best interests to follow them to the letter.

[Brett1970]

noooo lol i guess i shouldn't have said rivets. It's actually a screw, and i'm talking about the plastic dust boot itself. i have my bare strand wire attached to the base of the dust collector, through the dust hose, and i put an eyelet on the end, and it's attached to one of the screws on the dust boot, where it goes from the formed top, to the slatted sides. It's plastic to plastic right there, no metal involved.

Here's my thought. I'm going to cut the ground going from the machine frame to the dust collector, and go from the dust collector right to the earth ground in my breaker box. This shouldn't cause a ground loop that i can think of, since it will terminating at the plastic dust boot.

Here's a diagram of how it's grounded

[michael_schwartz]

I recently discovered that the cable guy broke my clamp where my electric panel attaches to my ground rod outside... he just left it!

Steve

somebody did that to the second grounding rod for my shop.... And of course the wire, had been loosely wrapped around the rod, having never been clamped to begin with. I don't even want to know who installed it. It is still laying on the ground, since it is not my responsibility to pay to have it redone properly.

[garyc]

David...
Delete your wire from (G) to (F). Verify as per Brady's instructions above.

[Brett1970]

Alright, i'm going to go get a spool of wire tomorrow, so i can eliminate the ground from table to dust collector, and go dust collector to breaker box.

[garyc]

David...
Assuming that the DC has a 3 wire cord, and you verify as per Brady's instructions, it is already grounded to the electical box. Adding the wire to the machine creates a ground loop.

[ken_rychlik]

I had one from C to F and also from B to the case of the PC. It was tagged to the x and y gantries as well along the way. Also the dust collector base was grounded to it's electrical supply ground just to be sure. My DC hose has the wire embeded in it and I didn't use an internal wire like most gurus on here will suggest. I tried the internal wire, but it kept getting clogged up with wood fragments.
Not sure mine was perfect, but it worked.