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Homing Position
« on: October 07, 2015, 07:53:21 PM »
I installed my homing switches based off of a couple mini mill examples on the internet.

Is the the correct position for "home?"

I am having trouble with the concept.  When I ref all home, it goes to this position in my example picture.  the thing I get confused about is when i jog away from its home position on the x or y, its a negative number. 

because of this confusion its hard for me to figure out my soft limits.

i have watched the mach3 tutorial on home switches, twice so far....im still just a bit confused.

If anyone could help explain this to me or point me in the right direction id appreciate it!


Offline RICH

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Re: Homing Position
« Reply #1 on: October 08, 2015, 06:12:17 AM »
When Mach ( the controller ) is started it does not know where Machine coordinate 0,0,0 is so the user must  define it to the controller.
Normally 0,0,0 would have the table positioned  to the left and nearest the operator with Z raised. You would define that position as HOME / Referenced.
Home can be any where but the above is conventional. The controller now knows where the machines 0,0,0 is and any move away from that position would be positive X & Y . Soft limits restrict the axis movements.

When Mach is started the default Work / Fixture offset G54 is used, thus if there is no  Work /Fixture  offset then, Machine coordinate 0,0,0 = Part Coordinate 0,0,0.

So have read of the Manual or again watch the video, with the above explanation in mind, and know what each input for an axis in Homing & Soft limits defines to the controller.

RICH

Re: Homing Position
« Reply #2 on: October 08, 2015, 03:25:20 PM »
Hi Brian:
Go to the "Member Docs" section of the forum, and download the pdf file; MACH 3 TUTORIAL - SETTING UP A BASIC 3 AXIS MILL

This is an excellent overview written by Henrik Olson showing all the basic steps necessary for Mach3.  He details everything, including the Home states, as well as how to set Soft limits with pictures of the Mach screens at each step.
Re: Homing Position
« Reply #3 on: October 08, 2015, 06:56:33 PM »
Thanks to both of you. 

"The most common location for the X- and Y-axis is probably at the most negative position of travel."

IF I am not mistaken thats where my table is in the original picture, which means, im somewhat getting it.

I guess the problem I am having is purely with soft limits.

This is my configuration in he pictures and the video shows what happens.

https://www.youtube.com/watch?v=43iN7mwIchc

If anyone see's anything im getting wrong, please let me know!  Thanks for your time!

Offline ger21

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Re: Homing Position
« Reply #4 on: October 08, 2015, 08:17:29 PM »
You need to look at it as the direction the tool is traveling, and not the direction the table is moving.
Gerry

2010 Screenset
http://www.thecncwoodworker.com/2010.html

JointCAM Dovetail and Box Joint software
http://www.g-forcecnc.com/jointcam.html
Re: Homing Position
« Reply #5 on: October 08, 2015, 08:20:06 PM »
Ok.

I'm not sure that explains the soft limit issue I'm experiencing.  Alhough I could be mistaken.

Offline ger21

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Re: Homing Position
« Reply #6 on: October 08, 2015, 08:33:53 PM »
Your X and Y axis are homing to the positive end of travel. Check the Home Negative boxes in Config>Homing Limits for the X and Y axis.
Gerry

2010 Screenset
http://www.thecncwoodworker.com/2010.html

JointCAM Dovetail and Box Joint software
http://www.g-forcecnc.com/jointcam.html
Re: Homing Position
« Reply #7 on: October 09, 2015, 08:16:21 AM »
I will give that a try this evening when I get home from work!  Thanks for that quick reply!!
Re: Homing Position
« Reply #8 on: October 09, 2015, 07:04:18 PM »
I checked the boxes you suggested and the machine started homing the wrong way on the x and y axis so i checked the reverse box to get them to home towards my limits switches.  I attached the updated picture of my configuration.

Still I get the soft limits kicking in towards where i have my home switches.

https://www.youtube.com/watch?v=DrjH_GUbhxo

Offline ger21

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Re: Homing Position
« Reply #9 on: October 09, 2015, 07:37:19 PM »
I don't use a mill, so I'm not sure which way the machine is supposed to home to.
However.
You have your machine set to home in the positive direction, in order to move towards your switches. This is why you're having trouble with softlimits. Anfter the machine homes, it only moves in the negative direction.
The way you have it setup now, your softlimits would need to be Max = 0, and min = -100.
I think that you may have the machine setup backwards. Either that, or your home switches are at the wrong end.

IF everything isd correct, and your home switches are at the positive end of travel, then set a Home Offset of 100 for the X and Y, then your softlimits should work. (although your max is probably more than 100? Set the Home Offset to the maximum travel distance, and softlimits to match)
Gerry

2010 Screenset
http://www.thecncwoodworker.com/2010.html

JointCAM Dovetail and Box Joint software
http://www.g-forcecnc.com/jointcam.html