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Author Topic: Parallel Cable Woes  (Read 6840 times)

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Offline Hood

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Re: Parallel Cable Woes
« Reply #10 on: August 12, 2008, 10:52:37 AM »
Will have to have a look at Arturos board, will have time this evening (3:50pm now) and will get back to you if I find anything, sounds like Arturos board may be a sinking input but as I have never used them I dont know. Gotta go get a few jobs finished and they are not going well LOL
Hood

Offline Hood

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Re: Parallel Cable Woes
« Reply #11 on: August 12, 2008, 03:24:03 PM »
Had a look and it seems you need 5V on an input pin for limits etc
 You say you have that but it doesnt work right? If you connect up a NC switch (limit) and look on the diagnostics age does the LED light up when you press it?
 If it des and you are still getting the problem try increasing the debounce to 2000 and see if it works correctly, if it does then lower the debounce until the problem reapears then back up again until it stops.
 Do you have shielded cables on the limits?
Hood
Re: Parallel Cable Woes
« Reply #12 on: August 12, 2008, 09:55:38 PM »
Hood, You are a genious!

I set debounce to 2000 and guess what, when I "Ref All Home"  the "Z" went to "Home" and then backed off a bit and then continued on to the other Axes as expected and did the same.

Very confusing when following the setup videos that are trying to be Generic but don't work for all BOB's.

Many thanks for your help. You managed to get one more CNC'er up and running. Keep up the good work.

Now I can concentrate on doing something worthwhile!

Hope I can somehow contribute to the Forum in the future.

Al
Re: Parallel Cable Woes
« Reply #13 on: August 13, 2008, 08:20:34 AM »
One final thing for the record, I wasn't using shielded cable to connect the Limit Switches in series.

Thanks again

Al

Offline Hood

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Re: Parallel Cable Woes
« Reply #14 on: August 13, 2008, 10:34:01 AM »
Always best to shield the signal cables, especially when its 5v as noise is a real problem due to the small difference between a high and low signal.

Hood
Re: Parallel Cable Woes
« Reply #15 on: August 14, 2008, 10:02:19 AM »
Trying to purchase shielded cable in a small town is frustrating since no one seems to know what it is.

We do have a Home Depot and they have something called CAT 5 Twisted pair cable but it doesn't specifically say it is shielded.
Will this work or could I use Coax Cable for this job. Do I ground the shield portion and if so where?

I am definitely getting interference from the 5v source. Too bad I can't use the common or ground sources on the board.

Al

Offline Hood

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Re: Parallel Cable Woes
« Reply #16 on: August 14, 2008, 01:07:43 PM »
You can get cable from the internet easily enough and probably a lot cheaper than locally. I get a lot of my cables from eBay in the UK and you often get real bargains ;)
 Cat 5 can be shielded but usually it is not, it is the the type of cable they use for networking computers and the twisted pair helps reduce noise but I dont think it would be so much help in limits.

Coax I think is usually just single core with shielding, you need twin core with shielding, also coax is often solid core and that should be avoided on a machine as vibration will eventually crack the core, you want multistrand cores as they are much more flexible and wont fatigue the same.
 The shield should be grounded only at one end and it is best that it is the control end. Also try and connect all of your ground wires at one single point in the case.

Hood