Machsupport Forum

Mach Discussion => General Mach Discussion => Topic started by: rjb on January 30, 2011, 12:28:36 PM

Title: Machine Not Moving Off Reference Switch
Post by: rjb on January 30, 2011, 12:28:36 PM
Until recently my machine has functioned correctly when I selected 'Ref All Home' ..each axis would move to the reference switch and reverse off it in turn, Z followed by Y followed by X.  However, for some reason it has stopped working correctly and now when I select 'Ref All Home' the Z axis references correctly, then the Y axis moves to the reference switch, but does not move off, then because it hasn't moved off the Y switch the X axis tries to reference in the wrong direction.  I don't think I've changed any settings to cause this, but I can't be sure.  Can anyone tell be why this is hapenning and how to rectify the problem?

Thanks,

Richard.
Title: Re: Machine Not Moving Off Reference Switch
Post by: RonC on February 13, 2011, 02:49:23 PM
Hi Richard,
Just cured a similar problem on my machine, make sure that you are using shielded cable and it is
securely connected to ground at the control box end only.
Regards
RonC
Title: Re: Machine Not Moving Off Reference Switch
Post by: Bob Braeking on August 19, 2012, 01:57:10 PM
I am having a similar problem.  Trying to cure it one axis at a time.  Working on x.  I installed shielded cable and ground the shield to the machine.  2 switches are wired in series NC, active low.  I have isolated the X axis from the others by placing it on pin 11 by itself.  One of the switches works properly, ie. when activated the axis reverses off the switch and zeros the DRO.  The other switch merely limits forward motion without resetting nor reversing off the switch.

I will attempt to solve it by increasing the "debouncing" in the general configuration tab.

Next isolate homing by setting x-- and x++ to port 0 and pin 0.

I shall give a full report after my findings.
Title: Re: Machine Not Moving Off Reference Switch
Post by: Bob Braeking on August 20, 2012, 04:59:19 AM
I have exhausted my ideas.  Anyone have another?
Title: Re: Machine Not Moving Off Reference Switch
Post by: Hood on August 20, 2012, 05:25:12 AM
Do the LEDs at the side of the DROs turn Green?
Do you get an E=Stop after the homing hits the switch that is not reversing?
Hood
Title: Re: Machine Not Moving Off Reference Switch
Post by: Bob Braeking on August 20, 2012, 07:29:23 AM
The one switch turns the LED green and reverses off the switch.  The other switch just triggers an e-stop.  Since both switches are in series I am completely baffled. 
Title: Re: Machine Not Moving Off Reference Switch
Post by: Hood on August 20, 2012, 08:51:49 AM
That points to it being a particularly bad switch and that it is bouncing when on the point of breaking.
Hood
Title: Re: Machine Not Moving Off Reference Switch
Post by: Bob Braeking on August 20, 2012, 10:52:20 PM
I installed a new switch this evening with no improvement in performance.  I went into the general logic config and increased the debounce interval to 60 which seemed to do the trick.  I started at 120 and worked my way down until it malfunctioned and went up 20. 

Question:  Will this setting on the debounce effect my motor accuracy in any way?

Bob
Title: Re: Machine Not Moving Off Reference Switch
Post by: Hood on August 21, 2012, 02:47:18 AM
60 will be fine :)
Hood