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Author Topic: Home Switch Sensitivity Problem  (Read 3140 times)

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Home Switch Sensitivity Problem
« on: March 31, 2008, 11:46:34 AM »
I'm setting up Mach 3 on a new CNC and I'm having problems with the Zero set-up. The prox switches are so sensitive that when I tell the software to reference an axis, it makes the switch but doesn't fully back off of it and the switch will flutter.

I don't see a setting for telling it to back off the switch to a soft limit in the config menu.

What I'd like the machine to do is reference the switch, then move in the + direction one inch, then zero the DRO and call that position home and Zero.

Am I missing something simple?

Re: Home Switch Sensitivity Problem
« Reply #1 on: March 31, 2008, 12:23:48 PM »
The Debounce setting in General Config properties helps control this- Do a search here on the forum for "Debouce" and you will find other posts where this issue has been addressed!

Good Luck,
Sid

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Re: Home Switch Sensitivity Problem
« Reply #2 on: March 31, 2008, 12:37:37 PM »
As Sid has said debounce will indeed solve your problem, how mach homes is the following. You tell Mach to home and it moves towards the switch, once triggered Mach then reverses the axis untill the switch is deactivated. Because you have a twitchy switch if yoiu set the debounce higher it should work better, try a setting of 2000 and if that works go lower until you start getting problems again.
 If you want your axis zero position to be other than at the switch, such as a lathes X axis where you want the zero position to be axis centre, you can set a home off. What this does is when you home it will do as above but instead of setting the DRO to zero (machine coordinates) it will set it to your home off amount. It wont however move the axis to the zero position as that could be dangerous (crashing tools etc)

Hood
Re: Home Switch Sensitivity Problem
« Reply #3 on: March 31, 2008, 12:51:57 PM »
Thanks guys, this is exactly what I wanted.
Re: Home Switch Sensitivity Problem
« Reply #4 on: April 01, 2008, 09:24:19 PM »
Just an FYI.

I could not get the debounce setting to work with the prox switches I was using. The switches had a 4mm range and I couldn't set the debounce high enough to get it to back off far enough without it hitting the switches because they were inline with the metal that makes them. Rather than re-align the switches with new mounts, I opted for mechanical plunger switches. All is good with them.

The debounce setting is a nice idea but it causes a lag in the axis recognition of the switch as well as the stop of it's reverse away from the switch. That's not good if the switch is in a position that interferes with that particular axis of travel. It tends to release the magic smoke from said switches.