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Author Topic: My first attempt at a CNC build.  (Read 48788 times)

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Offline Sam

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Re: My first attempt at a CNC build.
« Reply #10 on: March 30, 2009, 11:36:55 PM »
Looks like your well on your way!
"CONFIDENCE: it's the feeling you experience before you fully understand the situation."
Re: My first attempt at a CNC build.
« Reply #11 on: April 01, 2010, 06:49:10 PM »

Well, it's been a year and I have worked on my machine off and on some. Now I'm trying to finish the wiring, it's a little trickier than I thought.

A quick question, on the limit switches, do I run one wire and have them go to ground or do I need to run 2 wires to each switch. I got 6 switches and I'm mounting 2 on each axis. I'm trying to run the least amount of wire possible.

The E-stop board has spots for 8 switches, 3 grounds and pin1, the main board is for 4 axis machine. I'm trying to find the papers to it. ???
Thanks

Offline RICH

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Re: My first attempt at a CNC build.
« Reply #12 on: April 01, 2010, 08:36:21 PM »
Good going on your project. Glad to see someone having fun and getting a lot of self satisfaction.
Remember that you need to show pic'c of your first piece you do.
RICH

Offline Tweakie.CNC

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Re: My first attempt at a CNC build.
« Reply #13 on: April 02, 2010, 03:52:15 AM »
With regard to your limit switches - It is better to run two wires because the machine frame is not always all at the same potential (moving axis for example may only be electrically connected to the main frame via the slides bearings). Also ground loops are a potential source of noise pickup and subsequent problems. Don't forget to used screened cable (grounded at the controller end only, preferable to a single point ground connection).

Tweakie.
Success consists of going from failure to failure without loss of enthusiasm.  Winston Churchill.
Re: My first attempt at a CNC build.
« Reply #14 on: April 02, 2010, 08:53:13 AM »
Thanks Rich and Tweakie. I've got a couple days here to do some serious work on it. I hope I can get it at least close to finished.
I'm glad I didn't cut off the ground wire in the cable. So I just ground one end at the board.
I just realized I forgot about the power cord to the router!!! That would have been a hassle after everything else was together.

Offline RICH

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Re: My first attempt at a CNC build.
« Reply #15 on: April 02, 2010, 09:01:57 AM »
There are two grounds,one for the circuit and one for the shield. The circuit ground should go back to the same ground used for the source
, in this case the board. The shield should be grounded to say the controller frame / box.
RICH
Re: My first attempt at a CNC build.
« Reply #16 on: April 02, 2010, 09:36:00 AM »
Thanks Rich, electronics and pooters aren't my strong points. I'm best with good old mechanical stuff, if it moves I like it. I know electrons move but I can't see them.
So, I shouldn't ground the board to the frame? The power supply is grounded to the frame and the router will be, also.

Offline RICH

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Re: My first attempt at a CNC build.
« Reply #17 on: April 02, 2010, 11:31:41 AM »
Your missing a few points i made.
If you get 5V from a supply, it goes to the circuit, and then there is a ground wire to complete the circuit and  it should go back to the supply ground since the voltage difference to ground will be relative to the supply source and not some other ground.

On the shield part: Imagine it's raining out and the shield is keeping the rain from getting on the wires inside of it. So the rain on the
shield takes the water to some spot where it is collected and will not touch the internal wires. That spot can be an imaginary lake and all the shields from different cables go to that lake and then a big pipe takes all the water away to get rid of it. So the shield is protecting the
internal wires from picking up any noise ( signals which make no sense to your hearing ) and providing an easy path to ground to get rid of it. So shield ground has a very different use then a circuit ground.

I deal in pounds per hour and gpm so when it comes to circuits i could be all wet.  ;)
RICH
« Last Edit: April 02, 2010, 11:33:43 AM by RICH »
Re: My first attempt at a CNC build.
« Reply #18 on: April 02, 2010, 06:36:04 PM »
Ok, yes the DC voltage all has it's own ground. I was referring to the case of the source being grounded to the cabinet. I imagine that's for the 120 vac in, which is grounded to the case.
I think we are over thinking this, I just didn't know about the ground on the cable shielding. OK, so I know enough about electronics to get me in trouble. :o

Thanks for putting up with me. :)

Offline RICH

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Re: My first attempt at a CNC build.
« Reply #19 on: April 02, 2010, 07:22:42 PM »
No problem at all.  :D
RICH