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Soft limits causing other problems
« on: October 24, 2017, 11:19:02 PM »
Hello i am in the process of configuring my recently build machining center, that is why i am posting so often in the forum.

I was having some problems with my z height getting messed up after the program ended, as stated here:

http://www.machsupport.com/forum/index.php/topic,35811.msg245280.html#msg245280
Question 2.

So i found a user that is having a similar problem with the part being offset at an axis and also discovered my Y work coordinate was
getting messed up too after the program ending. as stated below:

https://forums.autodesk.com/t5/fusion-360-computer-aided/mach3-g43-and-g54-post-process-problems/td-p/6498480

In the message he discovers the problem:

Quote
"Update:
 
I figured it out!!!!!!   It was all my fault....go figure huh.  A bit embarrassing but anyways here is what I did and where I went wrong.
 
To begin, I was frustrated and decided to completely start over from the beginning as far as my setup on the mill and homing everything.  So as I was tearing everything apart I realized I may have  had the stock fixtured too far to the limits of my table.   I re positioned the stock, homed/zerod as you guys had advised and air tested.  No more weird offset!! I believe what was happening when the machine started, was it ran up against the soft limits and took off from there essentially resetting itself to an offset that would allow it to do its job just in a slightly different location.  When I would stop the program and push return to zero it would go to its "new zero" .   Now that I have it re-positioned I fired it up live, it has been running correctly for the last 1/2 hour and throwin chips like a dream.   What a relief.
 
So for now I would say that the Fusion Cam is good, no bugs.   I will leave the MDI alone.  How do I leave G28 in without it crashing?  It goes straight up past the limit and crashes.
Thank you again  @gearsoup and @daniel_lyall.
 
Josh"

He said something about soft limits messing up his work offset, so i decided to give a try,
i went there changed my soft limits values and suddenly my part was not being offset the program ended.
I got really surprised, but it got me curious, i was really configuring my soft limits the wrong way.

It made me realize two things:
1) I made a mistake with the values i inserted in the soft limits page.
2) I was having a problem that limit switch was being triggered when it hit home while "Ref All home"

So i thought this could be the problem, the first thought i am sure it's true, the second not so sure, because i didn't test yet.

My system home switches(zeros) are located to give my only negative coordinates.

X axis: zero at the extreme right, so to the left only negative coordinates. 400mm to the left
Y axis: zero at the extreme front, so backwards only negative coordinates. 330mm backwards
Z axis: zero on the top, so down only negative coordinates. 315mm down

I attached my problematic configuration as "softlimit.png"
And then attached what solved my problem as "softlimitsolved.png"

As you can see, i only change the soft max and it completely fixes the problem, the guy from the thread at autodesk website, tries to explain it as:

Quote
No more weird offset!! I believe what was happening when the machine started, was it ran up against the soft limits and took off from there essentially resetting itself to an offset that would allow it to do its job just in a slightly different location.

Does this check ?
Re: Soft limits causing other problems
« Reply #1 on: October 26, 2017, 06:59:12 PM »
bump