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Author Topic: Homing in Mach 3  (Read 9953 times)

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Homing in Mach 3
« on: March 08, 2006, 09:17:30 PM »
I've been using Mach 2 successfully, well ... that's exagerating since I'm a beginner, but everything seems to work as I expect it on Mach 2.  Anyway, when I switched to Mach 3, the homing function no longer works correctly.  The axes drive to the home switches, stop and reverse as normal, but they do not back off far enough to clear the switches.  Is there a configuration item I've missed?  The axes need to back off just a little farther to clear the switch.  I thought Mach 3 reversed and ran till the switches open -- true?  If that's the case, why isn't mine clearing the switch?  In diagnostics mode, the LEDs stay lit continuously once the axis reaches home.

-Larry
Re: Homing in Mach 3
« Reply #1 on: March 09, 2006, 08:08:15 PM »
So if I understand what you are saying I think you need to add some debounce... OR the other problem that you may be having is you need to put .1 in the Home Off (Under Config/ Homing and Limits)

That may not do it but it is a good place to start.
Fixing problems one post at a time ;)

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Re: Homing in Mach 3
« Reply #2 on: March 10, 2006, 01:12:29 AM »
Hey Brian,

What does "debounce" mean and how does one add it?
Re: Homing in Mach 3
« Reply #3 on: March 10, 2006, 06:53:59 AM »
Thanks -- I didn't see the Home Off parameter you mentioned -- I'll look for it. That's probably my problem.

My switches already have debouce circuitry. They are optical switches and I''ve looked at them with a O-scope and they are very clean.  Their output is a 7400 series digital gate with nice clean transitions.

For sshneider, bounce refers to the rapid variation in the elctrical signal coming off a switch.  Mechanical switches are particularly sucesptible to bouce.  As they open, the electrical signal through the contacts essentially chatters on/off very fast as the switch contacts separate -- then will clean up and go hi or low (depending on how the switch is wired).  If the computer interface is fast enough it will see these fast chattering signals and may react before the switch is fully open which can lead to false readings.  There are several ways to debounce a circuit.  If you need some schematics, let me know and I can email you some info.

-Larry
Re: Homing in Mach 3
« Reply #4 on: March 10, 2006, 07:59:58 AM »
This is on the Home/Limits page:
Fixing problems one post at a time ;)

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www.machsupport.com
Re: Homing in Mach 3
« Reply #5 on: March 10, 2006, 12:04:40 PM »
Larry, Thanks for the info.  The more I read & learn, the more I realize how much I have to learn.  I feel like Orville Wright walking into the cockpit of a space shuttle and I'm a bit jealous of most of you dudes who are so friggin' profecient at this stuff.  Anyway... I'd love to see a schematic- can you email to slshneider@hotmail.com please.

Thanks!

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Re: Homing in Mach 3
« Reply #6 on: March 10, 2006, 12:22:27 PM »
Hey Brian,

What does "debounce" mean and how does one add it?

It's in either Config>Logic or Config>State
Gerry

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Re: Homing in Mach 3
« Reply #7 on: March 10, 2006, 08:45:39 PM »
Brian,  Thanks for the info -- I can't believe I missed it!  I put in 0.1 and it works perfectly. :)

sshneider, I'd be happy to send you schematics for debouce but you may not a ned hardware solution.  I didn't know MACH 3 had a software debounce function.  Go to the CONFIG menu item, then to LOGIC and enter a debouce value of ~100 or 200.  See if that solves your problem.  If not, please send me a note at LDB20151@yahoo.com and I'll send the schematics.

Good luck!

Re: Homing in Mach 3
« Reply #8 on: March 10, 2006, 09:33:54 PM »
DUDES!!!

That fixed my problem (putting 100 in the debounce box)!  Thanks again (and again and again and again and again!!!)

Sid
Re: Homing in Mach 3
« Reply #9 on: March 11, 2006, 09:50:37 AM »
Nice got two in one shot!
Fixing problems one post at a time ;)

www.newfangledsolutions.com
www.machsupport.com