Re: [CAD_CAM_EDM_DRO] Limit Switch Cable Noise

It would be a good idea to twist the motor power leads and Power Supply AC
leads. Only ground one end of the shielded cable.

Harko

On 10/29/06, Apalais <apalais@...> wrote:
>
> I'm not 100% sure. But try checking your debounce on the switches. Make
> the value 2000. This might help. It is in the settings somewhere.
>
> I'm sure someone will tell you exactaly what to do!
>
> Peter
> Australia
>
> ----- Original Message -----
> From: cnc002@... <cnc002%40aol.com>
> To: CAD_CAM_EDM_DRO@yahoogroups.com <CAD_CAM_EDM_DRO%40yahoogroups.com>
> Sent: Saturday, October 28, 2006 7:04 PM
> Subject: Re: [CAD_CAM_EDM_DRO] Limit Switch Cable Noise
>
> In a message dated 10/28/2006 4:43:09 P.M. Eastern Daylight Time,
> salhab@... <salhab%40maktoob.com> writes:
>
> Hi all,
> I've been installing mechanical limit switches on my mill I've used
> shielded cables(about 10 feet) and ground them and set the switch on
> the normal close and Mach2 pin setup on Active High , every thing
> reads well , but once I turn Motor Power on limit switch trigger
> starts flashing very fast causing Mach2 to stop I think it is noise
> problem.
>
> I've read in Mach2 Manual in chapter 4.6.1 (Limit Switch Strategies)
> that I have to use 5VDC power supply with 470 ohm resistance parralel
> with mach2 pin (Fig 4.7).
>
> Does this solve my problem or should I look for a breakout board ?
>
> Thank,
> Shadi Salhab
>
> Shadi:
>
> Did I read your post correctly, you are putting a 470 ohm resistor in
> parallel with the input pin for you Mach2? I take that to mean you have a
> 470 ohm
> resistor across the contacts of your limit switches. If that is true, it
> isn't logical as you would NEVER end up with a completely open circuit
> across
> the switch, now, if the resistor is being used as a pull up or pull down
> resistor, that would be logical and 470 ohms is one of the normal values
> used for
> that purpose. Did you use twisted pair cable? It works much better than
> just
> normal shielded cable. Did you connect both ends of the shield to ground?
> Normally you connect only ONE end of the shield to ground. From your
> description it does sound like you are getting a lot of electrical noise
> when you
> start the motor(s). In some cases, it may also be necessary to use
> shielded
> wiring to the motors as well. Also, if the motor is AC you might need to
> put a
> resistor/capacitor network "noise suppressors" across the power leads to
> the
> motor. You also should put those noise suppressors across any AC coils
> that
> are used in relays or motor starters. All of this will help in correcting
> noise problems. If you can send me a little diagram of how you have your
> switches connected directly to _cnc002@... <_cnc002%40aol.com>_
> (mailto:cnc002@... <cnc002%40aol.com>) , maybe I
> can get a better picture and idea of what is happening.
>
> Randy Abernathy
> 4626 Old Stilesboro Road NW
> Acworth, GA 30101-4066
> E-mail: cnc002@... <cnc002%40aol.com>
>
> I furnish technical support, repair, and other related services for your
> industrial woodworking machinery. My background as Senior Service Engineer
> for
> the SCMI Group for nearly fifteen years with factory training, combines
> with
> my extensive background in electronics, mechanics, pneumatics, electrical
> and
> CNC machinery to offer you needed support for your machinery. Services
> include but are not limited to the following:
>
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>
>


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