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Author Topic: series limit switch configuration using one for the home as well  (Read 6310 times)

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Offline geone

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Re: series limit switch configuration using one for the home as well
« Reply #20 on: October 01, 2011, 03:57:03 PM »
it will reset @ 0.....still working on total total grounding and better shielding.  I can live with 50 (so far).
best to all

Offline RICH

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Re: series limit switch configuration using one for the home as well
« Reply #21 on: October 01, 2011, 05:57:32 PM »
Just a thought...I fabricated the control box of wood, thinking it might provide some resistance to noise

Glad you getting there. A wooden box will keep noise out when it's a pressure wave and can attenuate / diminish the intensity of the wave. The reason we can hear is because pressure waves at some some frequency  and within distance can vibrate the ear drum which in turns converts the pressure wave to impulses to the brain and the brain interprets it as something we understand or maybe understand. It does nothing for electrical noise. Electrical noise are numerous electrical fields / waves which you can't see and are composed of numerous frequencies. The electrical frequencies can be created numerous ways, mixed, transmitted, and even altered to pressure waves so we can hear them.

Now if you were to line or wrap the wooden box with metal ( say Al wrapping foil ), the metal linning can keep  the electrical noise out. You just created a shield.

Heck, while i am probably confusing you, have a read of this:

A shield is nothing more than a metal enclosure which provides a low reisistive path to ground.
Lets use the analogy that the air around us is really a snow storm full of electromagnetic
 energy ( noise ( signals we can't understand ), TV, radio signals, high and low signals, anything sparking, etc.
 They are there but we can't see them. A shield will keep what's inside from going outside and vise versa.
The shield can be totaly closed 100% or maybe have holes / an open braid say 50% which is open.
 Now that open braid shield can become closed if the snow is big ( so allowable openings, electricaly speaking
are dependent on frequency if your trying to keep radiating ( signal getting out of shield ) or
 conducting ( signal getting past / into or onto the conductor inside the shield).
 An accumilatiion of snow may not bother you while walking outside but if you never shook it off it may
 overpower your ability to walk. In order for the snow to stick it has to have a source
 ( something creating it/ motor, pulse frequency, transformer, kid playing with a sparkler ) and addtionaly it
needs to stick to you ( conduction, unlikely induction, sometimes a combination of conduction and radiation ( rain and snow mix ).
 Now if your snow clothes ( shield) lets the snow go easily to ground you don't have to worry about it bothering
 your walking, but....  watch out if a whole bunch comes down on you at once from a tree
( overload / a motor turning on and generating a lot of noise), right on your butt you go
( computer locks up, signal interference , loss of or addititons to  the steppers).
Now since your only walking back and forth and the snow falls equaly on each side of you
 ( common ground with equal resistance values) no big pile will form and interfere with the small
 pile of snow getting to the ground ( ground loop ) happens.

Earth ground is a term misunderstood in application. I will spare you another snow storm analogy ...... ;)
Have a read of the attached.


« Last Edit: October 01, 2011, 06:01:03 PM by RICH »

Offline geone

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Re: series limit switch configuration using one for the home as well
« Reply #22 on: October 04, 2011, 01:48:38 PM »

Thanks for taking the time to explain (quite eloquently I might add) the concept.  I will forever be on guard for a snow storm.  I think my noise is coming from the power supply (inside the box) and would not benefit from interior shielding since the breakout board is is the same box.  I have been able to reduce noise to a minimum by using a separate power supply for the breakout board and another for the drivers.  I am now considering a limit and home board that has additional filters and pin buffering.  I am running debounce @ 50 and the system runs consistently with no noise reset.  My goal is to get it down to 0 with off the shelf components.  thanks again for all your help