Machsupport Forum

Mach Discussion => General Mach Discussion => Topic started by: stringkilla on February 20, 2006, 11:29:25 AM

Title: Strange Things Occur
Post by: stringkilla on February 20, 2006, 11:29:25 AM
Yes, strange indeed. Well if I extend my arm toward the machine, and come within four to five inches of the frame. a limit switch triggers on. I haven't run any parts yet because of this occurrence. I have a two conductor wire, 22 gauge, taped to the mdf table with alum. tape, connecting the two limits to a shielded cable to my breakout board. It seems as if the electrical field of my body is grounding out the system, could this be so? Any ideas as to why this happens.
Title: Re: Strange Things Occur
Post by: John S on February 20, 2006, 11:34:36 AM
Have you ever worked on the busses?

Perhaps you are a bad conductor.

John S.
Title: Re: Strange Things Occur
Post by: Art on February 20, 2006, 12:03:02 PM
Hi:

 Your indusing noise and using your arm as an antennae

  Use a debounce of 2000 in the config/log, does that help any?

Art
Title: Re: Strange Things Occur
Post by: stringkilla on February 20, 2006, 12:32:04 PM
set debounce already at 2k and the index at 2k but it's still happening. Is it possible I may need to ground my machine to a bolt or screw ?
Title: Re: Strange Things Occur
Post by: stringkilla on February 20, 2006, 12:33:40 PM
Have you ever worked on the busses?

Perhaps you are a bad conductor.

John S.
no but i was once a pilot. i piloted it from here to there. hah hah....
Title: Re: Strange Things Occur
Post by: Keith on February 20, 2006, 01:21:07 PM
Try doing a 'twisted pair' for the wire(twist them,assuming they are solid,so they helix each other).The input must be a high impedance and I'll bet anything you're environment is nice and dry and you're arm is 'charged'
Title: Re: Strange Things Occur
Post by: sparky3 on February 20, 2006, 08:30:06 PM
are your limit swithces wired normally open or normaly closed?
Title: Re: Strange Things Occur
Post by: stringkilla on February 22, 2006, 05:12:43 PM
are your limit swithces wired normally open or normaly closed?
  I think they are normally open
Title: Re: Strange Things Occur
Post by: sparky3 on February 22, 2006, 05:48:21 PM
you may have to put pullup resistors on the break out board at each limit switch input. 
Title: Re: Strange Things Occur
Post by: stringkilla on February 23, 2006, 10:29:47 AM
Well if I add them just as a precaution, what values would I need? Please add your recommendations. Thank you.
Title: Re: Strange Things Occur
Post by: sparky3 on February 23, 2006, 05:35:19 PM
right now i am using 470 ohm right now from +5 volts through the resistor to the input