Machsupport Forum

Mach Discussion => General Mach Discussion => Topic started by: booda88 on October 04, 2013, 09:33:25 PM

Title: Limit / Home Switches
Post by: booda88 on October 04, 2013, 09:33:25 PM
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
Title: Re: Limit / Home Switches
Post by: rickinbeachcrest on October 06, 2013, 12:43:10 AM
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/

Title: Re: Limit / Home Switches
Post by: Hood on October 06, 2013, 04:21:54 AM
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
Title: Re: Limit / Home Switches
Post by: booda88 on October 06, 2013, 06:07:07 AM
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
Title: Re: Limit / Home Switches
Post by: ger21 on October 06, 2013, 07:07:30 AM
2000is actually rather low. Try setting it at 10,000 and see if it helps.
Title: Re: Limit / Home Switches
Post by: Hood on October 06, 2013, 07:37:13 AM
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
Title: Re: Limit / Home Switches
Post by: booda88 on October 06, 2013, 07:51:34 AM
Connected to the ground on the C11 break-out board on the limit switches
Title: Re: Limit / Home Switches
Post by: Hood on October 06, 2013, 07:54:45 AM
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
Title: Re: Limit / Home Switches
Post by: booda88 on October 06, 2013, 07:55:27 AM
I will move it Thanks
Title: Re: Limit / Home Switches
Post by: Hood on October 06, 2013, 07:56:31 AM
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
Title: Re: Limit / Home Switches
Post by: booda88 on October 06, 2013, 07:57:15 AM
I don't think it is the ground . I think I found a programing error. I will check that later today. Thanks
Title: Limit / Home Switches
Post by: Fastest1 on October 06, 2013, 08:30:15 AM
The shield is a drain for noise/stray signals. Connect at controller only (most of the time).
Title: Re: Limit / Home Switches
Post by: booda88 on October 06, 2013, 02:24:56 PM
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.
Title: Re: Limit / Home Switches
Post by: booda88 on October 06, 2013, 02:30:46 PM
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.
Title: Limit / Home Switches
Post by: Fastest1 on October 06, 2013, 06:18:29 PM
This is referred to as a star ground. Don't forget to bring your V- to this point also.