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Author Topic: Homing issue - Custom script?  (Read 2147 times)

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Homing issue - Custom script?
« on: February 02, 2014, 10:54:22 PM »
I have an issue with my homing routine. For some reason, my home switches/limit switches engage at a different position than they disengage. For example, while feeding Z up and normal speed, the homing switch engages, then the homing routine backs off until it disengages and sets that position as zero. The problem is it doesn't disengage at the same coordinate it engaged. The problem is the limit switch itself, and i'm not about to replace them. Because of the issue, when im jogging towards machine zero, i can go well past before the switch engages.

So my question is, is it possible to edit the "REFCOMBINATION" procedure so that it backs off completely after hitting at normal speed, then feeds at a slower rate until it engages again? Similar to a touch probe procedure? But since the Home and Limit switches are the same switch, is there a way to bypass the limit switches setting off an e-stop during the procedure?

Offline Hood

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Re: Homing issue - Custom script?
« Reply #1 on: February 03, 2014, 02:43:31 AM »
It is quite normal for mechanical switches to have a difference between Opening and again closing, usually its not much, maybe a few mm.
To do what you are wanting is simple, just go to config menu then Homing and Limits page and set a Home Off value. What that will do is instead of setting machine Coords to Zero at the switch they will be set to whatever value you have set.
Hood
Re: Homing issue - Custom script?
« Reply #2 on: February 03, 2014, 02:55:19 AM »
So what you are saying then is to measure what the difference is (hopefully it's consistent) and set the home off to that amount to accommodate for the difference between the two points?

Offline Hood

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Re: Homing issue - Custom script?
« Reply #3 on: February 03, 2014, 02:59:40 AM »
Yes you could do that.
On my machines I have separate home switches and the way I set mine up is I home and that sets the machine coords zero. I look at machine coords then use my MPG to move relatively slowly to the limit switches, when they are tripped the machine coords  DRO shows the distance past the home switch to the limit, so I just enter that vale (but as a positive instead of the negative it will show) into the Home Off box.
Hood
Re: Homing issue - Custom script?
« Reply #4 on: March 23, 2014, 04:24:09 PM »
hello friends;

i have a machine with homing and limit switch separatley.

the machine is doing the homing process proparly.

i ask if its possible to drag off the home switch (mechanical switch) more than closing the switch again.

in other meaning, i want the axes to return back more to free the switch more(i.e 10mm more drag off) and then to zero the DRO's
 
i hope i explain my self well.

regards;
Basim
Re: Homing issue - Custom script?
« Reply #5 on: March 23, 2014, 04:38:47 PM »
Set a "Home Off" value of 10 (in the proper direction) as Hood mentioned above, then add G53 X0 to the button script.
I think others have done this.

Russ