Off-scale Soft Limits Setting in EMC

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10 Oct 2011 14:18 - 10 Oct 2011 14:19 #13803 by NICKKINSMAN
I might be missing something simple here...I'm using a lathe with EMC V. 2.4.6.32

I've been trying to run some g-code on a new machine setup. When I initially setup the machine with soft limits and no 54 offsets (DRO was reading just machine coordinates) the machine homed and soft limits worked fine, no issues.

I've started trying to run some g-code programs, but the red box in EMC showing the machine limits appears way off from where the part is at (this is after X/Z touch off to set the part location). Even the tool location is showing way off from the red box. And I get the error code - 'out of machine limits' when I try and run the code (and the box over the dimension showing out of limit).

It still seems the soft limits are working, I ran the saddle around and it stops where it should. it almost seems like EMC is somehow confused on the graphical layout of the soft limits.

I'm running homing sequence at startup, and it seems to home up well. I noticed the DRO is still showing the last touch off coord system (as expected) when I startup.

Is there anything I should be doing at startup before homing to make sure it is getting the soft limits right? I'm setting up all my tools with Z=0 just off the chuck face, would that make any difference?

Thanks!
Nick
Last edit: 10 Oct 2011 14:19 by NICKKINSMAN.

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10 Oct 2011 14:30 - 10 Oct 2011 14:32 #13805 by BigJohnT
There is a bug in Axis calculating the machine limits when you have an offset which has been fixed in 2.4.7... hope we can get that by Christmas.

I do the same as you and touch off each tool to the spindle face using a 3/8 dowel and call that Z0 for the tool table. Then I take any (almost) tool and touch off the face of the part with the 3/8 dowel and touch off the G54 and enter 0.375.

www.youtube.com/user/Gnipsel#p/a/u/0/VmRUJk0ptN4

John
Last edit: 10 Oct 2011 14:32 by BigJohnT.

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10 Oct 2011 17:11 #13810 by NICKKINSMAN
Thanks for getting back, good to know I'm not way out there, am trying to follow the manual and get it to work.

What is the workaround for this? Choose the run anyway? I think I tried that and it did not want to 'run anyway' but I'll give it a shot again.

Thanks!

Nick

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10 Oct 2011 20:22 #13816 by BigJohnT
If it is truly out of limits the trajectory planner will not execute that line... if it is an Axis bug it will run fine when you select run anyway.

John

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10 Oct 2011 23:00 #13820 by andypugh
NICKKINSMAN wrote:

I've started trying to run some g-code programs, but the red box in EMC showing the machine limits appears way off from where the part is at


This isn't the bug that JT was talking about, I don't think.

Are you touching-off into the coordinate system or the tool table? (you can choose from a drop-down in the touch-off dialog)

I would suggest taking your most common tool, and making that the "base tool" then jog it to a known place in X and Y. Now touch off to the known coordinates in G54, and then into the tool table. That should set the tool offset to zero and the coordinates to suit the work, and you _should_ now see your tool tip and work inside the box.

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11 Oct 2011 18:15 #13840 by NICKKINSMAN
Replied by NICKKINSMAN on topic Touch off procedure
I was basically following the manual step-for-step for the tool changer. Select tool, jog to offset tool at the chuck, touch off 'Z=0', pick tool table, and OK, next tool, etc, same for all tools. Same for X, except input tool tip distance form C/L. (Ran a G94.1 to verify clear offsets).

Then I jogged to the end of part, and touch off X and Z=0 to G54, P1. That set everything on DRO to zero. (part zero is on C/L)

I am not sure what you mean by 'into the tool table'?

Nick

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11 Oct 2011 19:23 #13843 by andypugh
Replied by andypugh on topic Re:Touch off procedure
NICKKINSMAN wrote:

I am not sure what you mean by 'into the tool table'?


I meant pretty much what you are doing, pressing "touch off" then selecting the tool table from the drop-down.

Places where it could go wrong are
1) Not doing a g43 to select the tool offset
2) Starting off with a large offset in the tool table for the first tool, and transferring it as an offset to the others.

Try this sequence:

M6 T1 G43

Then, touch of the tool selecting G54, then touch it off again selecting "Tool Table" Do this for X and Z. Does this bring the preview back into the box?
If it does, you can now touch-off the other tools using "Tool Table" and you should be sorted out with T1 as the zero-length reference tool. (Which is fine, even if it isn't really zero-length)
Also, if you ever look at the tool table and see an offset in T1, you know something has gone wrong.

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12 Oct 2011 00:16 #13850 by BigJohnT
Replied by BigJohnT on topic Re:Touch off procedure
When you do a tool change you have to use Tn M6 G43 then select the Z axis then move to your touch off point then touch off the tool table and notice if it says Z. Then you can load a tool with Tn M6 G43 and select Z axis and touch off your stock to G54.

John

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13 Oct 2011 00:46 #13874 by NICKKINSMAN
Replied by NICKKINSMAN on topic Re:Touch off procedure
OK, yes I need to touch of the G54 then, I was not doing that, just touching off the tool table. I will do that.

Thanks!
Nick

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