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Author Topic: Limit Switches Hard and Soft  (Read 5665 times)

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Offline wisconsinjimmy

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  • 8 8
Re: Limit Switches Hard and Soft
« Reply #10 on: February 25, 2018, 11:12:15 AM »
Craig,
This is where I get totally dumbfounded, I think the LIMIT switch is the one you install at the end of an axis to shut the machine off before it can cause damage to itself.
Home switch is what Mach3 controls and is installed  digitally.
I also need some help on this LIMIT switches, I am using a HobbyCNC control board and pin 13 for my LIMIT switch also I should mention that I am using a UC100 instead of the Parallel cable. Where do I set my limit switch in Mach3
Thanks for the help
As always
God Bless
Jim Ganley
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Offline Davek0974

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  • 2,606 2,606
Re: Limit Switches Hard and Soft
« Reply #11 on: February 25, 2018, 11:18:34 AM »
Yes LIMIT is a physical switch at the end of each axis travel, its optional, you could fit it as just a HOME switch or let mach3 use the limit as a combined home and limit switch.

I would install as a home switch as you only need one switch per axis and then setup soft limits.

If using limit switches you need one at the end of each axis.
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Offline joeaverage

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  • 7,586 7,586
Re: Limit Switches Hard and Soft
« Reply #12 on: February 25, 2018, 12:52:06 PM »
Hi,
have you worked out how to tune the motors yet?

Limit and home switches are pointless until you've got that right.

Craig
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Offline wisconsinjimmy

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  • 8 8
Re: Limit Switches Hard and Soft
« Reply #13 on: February 25, 2018, 04:34:34 PM »
I have went to the Setting Tab and moved my y axis to the center line of the table and just off the mechanical limiter switch, I then entered 14mm hit OK and the y went 7mm 1/2 of what I want?
I have moved the X to the left and just touching the limit switch,  entered 14mm  and got 14 mm and Mach3 asked if I wanted to set the the X to 4000 steps per Unit? I replied yes,
What is wrong with the y.
I have moved Z to the top and dropped it -9mm and that was acceptable, Z axis will be set to 1800 steps per.
« Last Edit: February 25, 2018, 04:50:00 PM by wisconsinjimmy »
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Offline Davek0974

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Re: Limit Switches Hard and Soft
« Reply #14 on: February 25, 2018, 04:38:45 PM »
so you set the x and not the y?

you need to repeat the adjustment for the y axis, that should help

when you go to auto setting there are buttons for each axis - choose y and try that

once you get them working you need to repeat the settings with as much travel as possible - 14mm is far too short for accuracy
« Last Edit: February 25, 2018, 04:40:54 PM by Davek0974 »
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Offline wisconsinjimmy

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  • 8 8
Re: Limit Switches Hard and Soft
« Reply #15 on: February 25, 2018, 04:52:33 PM »
So what I want to do is use the full length and width of the table/
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Offline Davek0974

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  • 2,606 2,606
Re: Limit Switches Hard and Soft
« Reply #16 on: February 26, 2018, 02:12:24 AM »
Its always best when setting distances and checking them to use as much travel as you can measure accurately - it reduces errors/increases accuracy.
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Offline Tarzan

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  • 22 22
Re: Limit Switches Hard and Soft
« Reply #17 on: February 28, 2018, 05:11:40 AM »
I am right in the middle of this very same struggle. However, after messing with the “steps per” I’m Mach for a few hours trying to figure out why my axis’s would only move half as far as They should. I found out that the the drivers have a half step dip switch. I flipped that and then the distances work great. I am now trying to figure out my home/limits switches. I will have to start a new thread for myself and try and get a little help. with that portion.
« Last Edit: February 28, 2018, 05:15:06 AM by RICH »
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Offline joeaverage

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  • 7,586 7,586
Re: Limit Switches Hard and Soft
« Reply #18 on: February 28, 2018, 05:22:08 AM »
Hi,
you would be advised to leave half-stepping active and double the steps per unit setting. In fact just about all stepper powered CNC axes are operated at some sort
of microstepping, commonly 8 microsteps per full step or 16 microsteps per fullstep.

Its nice to think that the resolution improves as you introduce microstepping but the truth is the gain is illusory. The real advantage is smoothness of motion.
Midband resonances are very much reduced with microstepping.

If your driver allows 8 microstepping then increase the steps per in Mach by a factor of 8 as well.

Craig
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Offline Tarzan

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  • 22 22
Re: Limit Switches Hard and Soft
« Reply #19 on: February 28, 2018, 06:53:03 AM »
Quote from: joeaverage on February 28, 2018, 05:22:08 AM
Hi,
you would be advised to leave half-stepping active and double the steps per unit setting. In fact just about all stepper powered CNC axes are operated at some sort
of microstepping, commonly 8 microsteps per full step or 16 microsteps per fullstep.

Its nice to think that the resolution improves as you introduce microstepping but the truth is the gain is illusory. The real advantage is smoothness of motion.
Midband resonances are very much reduced with microstepping.

If your driver allows 8 microstepping then increase the steps per in Mach by a factor of 8 as well.



Craig


I didn’t know that. Thank you fo the information. I will try that
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