Machsupport Forum
Mach Discussion => General Mach Discussion => Topic started by: booda88 on October 04, 2013, 09:33:25 PM
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I switched over to servos from stepper motors and the axis will not back off the limit switches. The breakout board is a CNC4PC-C11, with Geckodriver G320X and a KL34-180-72 servo motor. All limit and encoder wires are shielded.
When the axis go to the limit it stops but can not move it off the limit switch. Any ideas. HELP
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There is an override button that will allow you to move off the limit switch. I've only used it once or twice so I don't remember the details. I think it is mentioned in the Homing, limits and offsets video.
http://www.machsupport.com/videos/
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Are you meaning when you are homing it hits the switch but then an E-Stop is called because the switch is then seen as a limit rather than a home?
If that is the case then it is one of two things, you have noise or you have bouncing switches. Both can be helped by setting a Debounce Interval in General Config page but really you shouldnt have to do that if you have the wiring properly shielded and grounded.
If you attach your xml and I will look to see if your config is correct.
Hood
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I have the Debounce Interval set at 2000 and it still will not work the wiring is shielded on both the limit switches and the encoders. I will get the iml and post it if I can.Thank you for your help
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2000is actually rather low. Try setting it at 10,000 and see if it helps.
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Have you got the shielding connected to one single point? Is the shielding only connected at one end of the cable.
Regarding 2000 being a low setting, it depends on your perspective, anything other than Zero is a high setting in my opinion :-)
Hood
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Connected to the ground on the C11 break-out board on the limit switches
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I do not know anything about the C11 but normal practice is to connect shields to a single stud in your control cabinet and that stud also be connected to Earth.
Hood
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I will move it Thanks
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Just a thought, are you using the shield as a conductor?
In other words are you using the shield for your 0v for your circuit?
Hood
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I don't think it is the ground . I think I found a programing error. I will check that later today. Thanks
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The shield is a drain for noise/stray signals. Connect at controller only (most of the time).
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No I have a wire going to each of the connections on the micro switch and the shield is a different wire attached to the braiding.
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No There is adifferent wire going to each of the connections on the micro switch. The shield is braided with a wire going to the board ground which I am going to change to case/earth ground.
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This is referred to as a star ground. Don't forget to bring your V- to this point also.