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Author Topic: Switches behave strangely  (Read 5696 times)

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Offline Hood

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Re: Switches behave strangely
« Reply #10 on: August 03, 2011, 05:16:44 AM »
Shielding and properly grounding the shield is usually good enough, sometimes people will add small capacitors on the inputs, think 0.1uF is the norm.
Hood

Offline Tweakie.CNC

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Re: Switches behave strangely
« Reply #11 on: August 03, 2011, 06:41:34 AM »
Isaac,

You would be wise to use twin core shielded cable to connect your switches with the shield connected to GND at the breakout board / controller end only.
The 0.1uF capacitors that Hood mentioned connect between the switch input and GND , again at the breakout board / controller end.

Tweakie.
KEEP SAFE !
Re: Switches behave strangely
« Reply #12 on: August 03, 2011, 07:59:20 AM »
Thanks heaps guys

I will go with the capacitors option for starters - easier then start rewiring all.

Hope this will solve this issue.

Cheers from down under

Isaac
Re: Switches behave strangely
« Reply #14 on: August 03, 2011, 08:30:25 PM »
Thanks for the info NosmoKing :-)

It may sound silly but I need to clarify one thing:

My Hobby CNC BOB came with an American mains plug. Since I did not wish to have any issues - I hooked this plug and using it with an international adaptor.

My dumb question: Where (if at all) does the American plug take it's ground from ? Is it possible I have no ground on the socket ? If this is true - where does the BOB take it's ground from ?

Does the Parallel port of the PC transfer ground somehow ?

Cheers

Isaac
Re: Switches behave strangely
« Reply #15 on: August 04, 2011, 09:32:02 AM »
The US and generally other countries Australia included,  use a similar system, for ground you require a 3 conductor supply, Live, neutral and ground.
Although the Earth ground and neutral are made common at the service entrance (power panel), they must remain separate throughout.
IOW you cannot use the ground in place of a neutral conductor, or vise-versa..
A normal tower or desk top PC has a 3 conductor supply and the ground is connected to the case, the power supply DC starts out essentially isolated, but the low voltage DC common is then connected  to earth ground through the MB screws to the case.
So the parallel port 5v common will also be at earth ground.
One problem that often causes confusion is that the term Ground that used to refer strictly to Earth ground and has also now become the term for P.S. common, and a P.S. common may or may not be connected to earth ground!!! ::)
N.
 


 
Re: Switches behave strangely
« Reply #16 on: August 04, 2011, 06:56:01 PM »
Thanks for that.

So I understand I have ground to my system (I am using a desktop) and the interference I get is probably form the motors/power etc.

Will install the capacitors and see how it goes.

Cheers


Isaac
Re: Switches behave strangely
« Reply #17 on: August 08, 2011, 05:40:07 AM »
Hello again guys

Time to report:

Today I installed 0.047 uF ceramic disk capacitors on each of the switches pins - and it looks like it works ! :-)

Had a minor issue with the shared homing switches - when trying to home - the limit part of the switch was triggered- not allowing me to reference.

Since I tried this with the debounce interval at zero - I have tried some settings and I have found out that 200 on the debounce is holding perfectly - I can now home/ref and I did not get any interference at all.

Thanks heaps for your support and wisdom guys - it is very much appreciated.

Isaac
Re: Switches behave strangely
« Reply #18 on: August 08, 2011, 04:39:10 PM »
Good day:

I am new to CNC and Mach3 and am also having issues with the switches.  I have hooked up all my switches and when i ask the machine to home itself the z switch turns system off , it does not back off the switch as do the y and x axis home switches.  I have made sure that the z switch is found as a home switch only and even played with resetting the home zero after backing it of .25".

The funny part is it worked once. When I first set up all my switches and axis were all over the place I pressed  home and all homed nicely. Z than y and finally x. The problem is it has never worked since.

As z is the first axis that homes it stays on off and I have to manually back it off and hit reset. Than it just homes z again etc.

Any help would be greatly appreciated.

Chieffy

Offline Hood

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Re: Switches behave strangely
« Reply #19 on: August 08, 2011, 05:01:21 PM »
Can you attach your xml as it will let me see if there are conflicts or issues with your setup.
Hood