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Author Topic: How can I turn a home switch also into a limit switch?  (Read 281 times)

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How can I turn a home switch also into a limit switch?
« on: August 29, 2020, 12:11:49 PM »
I'm missing something when attempting this in Mach 3.

I have all the switches so they home into the front of the machine, to the left, with the spindle going up. I hit "ref all home" and they all hit their switches and then back off a tiny bit.

I have a kamikaze Z axis, and when running a g-code will often start out plunging up, or if it doesn't do that it plunges down several inches a minute or so into a carve.  I would like so when it goes up and hits the switch it stops instead of trying to crush the switch.

How do I do this?

Offline Graham Waterworth

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Re: How can I turn a home switch also into a limit switch?
« Reply #1 on: August 29, 2020, 08:06:54 PM »
Slow down the homing speed in homing and limits to 20% or less.
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Re: How can I turn a home switch also into a limit switch?
« Reply #2 on: August 29, 2020, 11:49:24 PM »
I have that set right. 

The problem is that it works fine while homing.  The switches stop it and work just fine.  It's when I'm running a g-code.  The switches don't stop squat.

Offline TPS

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Re: How can I turn a home switch also into a limit switch?
« Reply #3 on: August 30, 2020, 04:19:09 AM »
have you set Home Input and Axis++,Axis-- Input to the same port and pin?
anything is possible, just try to do it.
if you find some mistakes, in my bad bavarian english,they are yours.

Offline ZASto

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Re: How can I turn a home switch also into a limit switch?
« Reply #4 on: August 30, 2020, 10:59:35 AM »
You can set Home and Limit switch to same pin.
During the homing cycle, switches are working as Home switches. In all other situations they are treated as Limit switches.
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Re: How can I turn a home switch also into a limit switch?
« Reply #5 on: August 30, 2020, 04:11:09 PM »
Thank you!

Offline ZASto

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Re: How can I turn a home switch also into a limit switch?
« Reply #6 on: August 30, 2020, 04:48:43 PM »
You're welcome!
Make no mistake between my personality and my attitude.
My personality is who I am.
My attitude depends on who you are.
Re: How can I turn a home switch also into a limit switch?
« Reply #7 on: August 31, 2020, 04:10:20 PM »
Bummer, I did this, yet when the Z axis goes too high it still does not turn off, but screams as it tries to crus the switch until I hit the escape button.  :(

Offline TPS

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Re: How can I turn a home switch also into a limit switch?
« Reply #8 on: September 01, 2020, 02:44:19 AM »
if you go to diagnostic page and hit your Switch manually, can you see M3++Lim Led changing status?
anything is possible, just try to do it.
if you find some mistakes, in my bad bavarian english,they are yours.

Offline reuelt

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Re: How can I turn a home switch also into a limit switch?
« Reply #9 on: September 12, 2020, 09:01:13 PM »
Bummer, I did this, yet when the Z axis goes too high it still does not turn off, but screams as it tries to crus the switch until I hit the escape button.  :(
You may need to make sure that all your "Soft limits settings" are correct first.
I set soft limits so that soft limits are triggered 0.1 inch BEFORE positive direction limit switches are hit  even though my shared limit/home switches are working.
Soft limits will ensure the motion will automatically slow down when it the near the limit positions. Also, a negative direction Z softlimit can can be used to stop long tools hitting the vise bottom or machine surface below the the spoil board.
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